RBSE Solutions Class 10 Science Chapter 2 Human System

I. Multiple Choice Questions

Question 1. Which of the following controls the movement of food, digested food and waste materials?
(a) Sphincters
(b) Mucosa
(c) Submucus Layer
(d) Both 'b' and 'c'
Answer: (a) Sphincters
In simple words: Sphincters are like gates in our body that open and close to control where food and waste go, making sure they move in the right direction. They are found in many places, like at the end of the stomach and the anus.

🎯 Exam Tip: Remember that sphincters are crucial for unidirectional flow and preventing reflux in the digestive tract.

Question 2. Which type of teeth is most prominent in carnivorous animals?
(a) Incisor
(b) Canine
(c) Premolar
(d) Molar
Answer: (b) Canine
In simple words: Carnivorous animals have very strong and sharp canine teeth. These teeth help them to tear meat easily, which is important for their diet.

🎯 Exam Tip: Relate tooth type to diet: incisors for cutting, canines for tearing, molars and premolars for grinding.

Question 3. What is the main function of epiglottis?
(a) To send food in pharynx
(b) Prevent food from going into windpipe
(c) To send food into oesophagus
(d) None of the options
Answer: (b) Prevent food from going into windpipe
In simple words: The epiglottis acts like a lid. When you swallow food, it closes over your windpipe to stop food from entering your lungs and makes sure it goes down your food pipe instead.

🎯 Exam Tip: The epiglottis is a vital flap that protects the respiratory system during swallowing, preventing choking.

Question 4. Majority of digestion by enzymes takes place in which part of alimentary canal?
(a) Duodenum
Answer: (a) Duodenum
In simple words: The duodenum is the first part of the small intestine where most of the enzyme-driven digestion happens. Here, food mixes with digestive juices from the pancreas and liver to break down.

🎯 Exam Tip: Remember the duodenum's role as the primary site for chemical digestion due to receiving secretions from accessory organs.

Question 5. Which of the following is not a salivary gland?
(a) Parotid
(b) Sublingual
(c) Madibular
(d) Pituitary gland
Answer: (d) Pituitary gland
In simple words: The pituitary gland is a master gland in the brain that controls hormones, not saliva. Parotid, sublingual, and submandibular (not madibular) are actual salivary glands in the mouth.

🎯 Exam Tip: Distinguish between endocrine glands (like pituitary, which makes hormones) and exocrine glands (like salivary glands, which make saliva).

Question 6. Which enzyme is not secreted by pancreas?
(a) Amylase
(b) Trypsin
(c) Rennin
(d) Lipase
Answer: (c) Rennin
In simple words: The pancreas makes enzymes like amylase, trypsin, and lipase for digestion. Rennin is an enzyme found in the stomach of young animals (and some human infants) to help digest milk.

🎯 Exam Tip: Keep in mind that rennin's primary role is milk protein digestion, distinct from pancreatic enzymes that handle carbohydrates, proteins, and fats.

Question 7. Which of the following is a secondary respiratory organ?
(a) Mouth
(b) Nose
(c) Nasopharynx
(d) Trachea
Answer: (a) Mouth
In simple words: While we usually breathe through our nose, the mouth can also be used for breathing, especially when the nose is blocked. This makes the mouth a secondary breathing route.

🎯 Exam Tip: Remember that the nose is the primary organ for breathing, as it filters, warms, and humidifies air, but the mouth serves as an alternative airway.

Question 8. How many lobes are present in the left lung?
(a) 3
(b) 4
(c) 2
(d) Other option
Answer: (c) 2
In simple words: The left lung in humans has two lobes. It is slightly smaller than the right lung because it needs to make space for the heart.

🎯 Exam Tip: Distinguish between the left and right lungs: the left typically has 2 lobes, and the right has 3 lobes.

Question 9. Which of the following is present in alveoli?
(a) Stratified epithelium
(b) Epithelium
(c) Cartilaginous rings
(d) None of these
Answer: (b) Epithelium
In simple words: Alveoli, which are tiny air sacs in the lungs, are lined with a very thin layer of simple epithelium. This thin lining helps in the easy exchange of gases like oxygen and carbon dioxide.

🎯 Exam Tip: Note that the thin, single-layered squamous epithelium of the alveoli is crucial for efficient gas exchange in the lungs.

Question 10. What is the name of the liquid portion of blood?
(a) Serum
(b) Lymph
(c) Plasma
(d) None of these
Answer: (c) Plasma
In simple words: Plasma is the yellowish liquid part of blood that carries blood cells, nutrients, hormones, and waste products throughout the body. It makes up about half of the blood's volume.

🎯 Exam Tip: Remember that plasma is mostly water, acting as a transport medium, while serum is plasma without clotting factors.

Question 11. Red Blood Cells are produced by which of the following?
(a) Spleen
(b) Bone marrow
(c) Lymph nodes
(d) None of these
Answer: (b) Bone marrow
In simple words: Red blood cells, which carry oxygen, are mainly made in the bone marrow. This spongy tissue inside bones is a factory for new blood cells.

🎯 Exam Tip: The bone marrow is the primary site for the production of all types of blood cells, including red blood cells, white blood cells, and platelets.

Question 12. Which of the following is not a white blood cell?
(a) B-lymphocyte
(b) Platelet
(c) Basophil
(d) Other option
Answer: (b) Platelet
In simple words: Platelets are small cell pieces that help blood clot, while B-lymphocytes and basophils are types of white blood cells that fight infections. Platelets are crucial for stopping bleeding.

🎯 Exam Tip: Recall the main blood components: Red Blood Cells (oxygen transport), White Blood Cells (immunity), and Platelets (clotting).

Question 13. Blood group AB has which antigens?
(a) 0
(b) A
(c) B
(d) AB
Answer: (d) AB
In simple words: People with AB blood type have both A and B antigens on their red blood cells. This means they can receive blood from any blood type.

🎯 Exam Tip: Understand that the presence of A and B antigens determines blood type, and AB blood group has both, making them universal recipients.

Question 14. Blood crosses through heart how many times during a cardiac cycle?
(a) One
(b) Three
(c) Two
(d) Four
Answer: (c) Two
In simple words: In a complete cardiac cycle, blood flows through the heart twice. Once it goes to the lungs to pick up oxygen, and then it comes back to the heart to be pumped to the rest of the body.

🎯 Exam Tip: Remember "double circulation" in humans, where blood passes through the heart twice: once through the pulmonary circuit and once through the systemic circuit.

Question 15. What is the main excretory product in humans?
(a) Ammonia
(b) Uric acid
(c) Urea
(d) Both 'a' and 'c'
Answer: (c) Urea
In simple words: The main waste product that humans remove from their bodies through urine is urea. It is less toxic than ammonia and can be safely transported in the blood.

🎯 Exam Tip: Understand the differences between ammonia, urea, and uric acid as excretory products, noting their toxicity and water requirements for removal.

Question 16. Glomerulus is present in which of the following?
(a) Bowman's capsule
(b) Renal tubules
(c) Loop of Henle
(d) None of these
Answer: (a) Bowman's capsule
In simple words: The glomerulus is a tiny ball of blood vessels that sits inside a cup-shaped part called Bowman's capsule in the kidney. This is where blood filtration begins.

🎯 Exam Tip: Visualize the nephron as the kidney's filtering unit, with the glomerulus and Bowman's capsule forming the initial filtration barrier.

Question 17. Which of the following is a male sex hormone?
(b) Progesterone
(c) Testosterone
(d) Both 'b' and 'c'
Answer: (c) Testosterone
In simple words: Testosterone is the main male sex hormone responsible for male characteristics and reproductive functions. Progesterone is primarily a female hormone.

🎯 Exam Tip: Know the key sex hormones: testosterone in males and estrogen and progesterone in females, and their primary roles.

Question 18. Which of the following is the primary sex organ?
(a) Scrotum
(b) Ovary
(c) Testis
(d) Both 'b' and 'c'
Answer: (d) Both 'b' and 'c'
In simple words: Both ovaries in females and testes in males are primary sex organs. They produce sex cells (eggs and sperm) and sex hormones, which are essential for reproduction.

🎯 Exam Tip: Primary sex organs are those that produce gametes (sperm/egg) and sex hormones, distinct from secondary sex organs involved in delivery or support.

Question 19. Motor neurons carry signals
(a) From central nervous system to organs
(b) From organs to central nervous system
(c) Both 'a' and 'b' are correct
(d) Both 'a' and 'b' are incorrect
Answer: (a) From central nervous system to organs
In simple words: Motor neurons are like messengers that carry commands from the brain and spinal cord to muscles and glands. This tells them what to do, like move a hand or release a hormone.

🎯 Exam Tip: Differentiate between motor neurons (efferent, carrying signals away from CNS) and sensory neurons (afferent, carrying signals towards CNS).

Question 20. Corpora quadrigemina is present in
(a) Forebrain
(b) Hindbrain
(c) Midbrain
(d) Both 'a' and 'b'
Answer: (c) Midbrain
In simple words: The corpora quadrigemina is a part of the midbrain. It is involved in processing visual and auditory reflexes, helping us respond quickly to sights and sounds.

🎯 Exam Tip: Locate brain structures by their main divisions (forebrain, midbrain, hindbrain) and recall their key functions.

Question 21. Which of the following is responsible for regulation of circadian variations?
(d) Pineal gland
Answer: (d) Pineal gland
In simple words: The pineal gland, located in the brain, produces melatonin. Melatonin is a hormone that helps control our sleep-wake cycle, also known as circadian rhythms.

🎯 Exam Tip: Associate the pineal gland with melatonin production and the regulation of circadian rhythms.

Question 22. Which of the following is responsible for regulation of circadian variations?
(a) Thyroid gland
(b) Pancreas
(c) Adrenal gland
(d) Pineal gland
Answer: (d) Pineal gland
In simple words: The pineal gland, found in the brain, makes a hormone called melatonin. This hormone helps to manage our body's sleep and wake times, which are its natural daily rhythms.

🎯 Exam Tip: Remember that the pineal gland is the primary endocrine gland responsible for regulating the sleep-wake cycle through melatonin secretion.

Human System Very Short Answer Type Questions

Question 23. Name the fundamental structural and functional unit of body.
Answer: Cell. The cell is the smallest basic unit of life that can perform all life processes. It is the building block of all living things.
In simple words: The basic unit of every living thing is a cell. It is like the smallest brick that builds up a house.

🎯 Exam Tip: Emphasize that the cell is the fundamental unit, meaning it's the smallest entity capable of independent existence and performing life's essential functions.

Question 24. Define the digestive system.
Answer: The digestive system is the body system that breaks down food into simple, absorbable substances. These smaller parts can then be used by the body for energy, growth, and repair.
In simple words: The digestive system changes food into tiny pieces so our body can use it.

🎯 Exam Tip: Key terms for defining the digestive system are "break down food" and "absorbable substances for energy/growth."

Question 25. What is the function of sphincters?
Answer: Sphincters are circular muscles that control the movement of food through the alimentary canal. They also prevent the backflow of food, ensuring it moves in only one direction. These muscle rings act like valves to regulate flow.
In simple words: Sphincters are muscles that open and close to let food move forward and stop it from going backward.

🎯 Exam Tip: Highlight "control movement" and "prevent backflow" as the two primary functions of sphincters in the digestive tract.

Question 27. What is the function of incisor teeth?
Answer: Incisor teeth are located at the front of the mouth and are primarily meant for cutting food. Their sharp, chisel-like edges help in biting off pieces of food. They are the first teeth to meet the food.
In simple words: Incisor teeth are the front teeth used to cut food into smaller pieces.

🎯 Exam Tip: Relate incisors directly to their function of "cutting" or "biting" food, as they are the first point of contact.

Question 28. The stomach has how many parts?
Answer: The stomach has three main parts: the cardiac region, the fundus, and the pylorus. Each part plays a specific role in digestion. The cardiac region is where food enters from the esophagus.
In simple words: The stomach has three parts: cardiac, fundus, and pylorus.

🎯 Exam Tip: Clearly list the three parts of the stomach: cardia, fundus, and pylorus, as these are distinct anatomical regions.

Question 29. Most of the digested food is absorbed in which part of alimentary canal?
Answer: Absorption of digested food primarily happens in the jejunum, which is the middle part of the small intestine. The small intestine's long length and inner folds provide a large surface area for nutrient absorption. The jejunum has many folds and finger-like projections called villi, which increase its surface area for absorption.
In simple words: Most digested food is taken into the blood in the jejunum, the middle part of the small intestine.

🎯 Exam Tip: Highlight the jejunum as the main site for nutrient absorption in the small intestine due to its extensive surface area.

Question 30. Which is the largest gland in human body?
Answer: The liver is the largest gland in the human body. It has many important functions, including detoxifying harmful substances, producing bile for digestion, and storing nutrients.
In simple words: The liver is the biggest gland inside the human body.

🎯 Exam Tip: Remember that the liver is not only the largest gland but also performs a vast array of metabolic and digestive functions.

Question 31. The enzyme ptyalin is secreted by which gland?
Answer: The enzyme ptyalin is secreted by the salivary glands. Ptyalin, also known as salivary amylase, starts the digestion of carbohydrates in the mouth. It breaks down complex carbohydrates into simpler sugars.
In simple words: Ptyalin enzyme comes from the salivary gland in our mouth.

🎯 Exam Tip: Connect ptyalin (salivary amylase) to salivary glands and its role in initiating carbohydrate digestion in the mouth.

Question 32. The voice box contains how many cartilages?
Answer: The voice box, also known as the larynx, contains nine cartilages. These cartilages work together to form the structure of the larynx and support the vocal cords, which produce sound.
In simple words: The voice box, or larynx, has nine pieces of cartilage.

🎯 Exam Tip: Remember the larynx (voice box) is made of cartilage, and the number nine is specific for its structure.

Question 33. What is the approximate total blood volume in a human adult?
Answer: Approximately 5 litres. The average adult human body contains about 5 litres of blood, which circulates throughout the body, delivering oxygen and nutrients. This volume is crucial for maintaining proper bodily functions.
In simple words: An adult human body usually has around 5 litres of blood.

🎯 Exam Tip: Know the approximate blood volume in an adult human, which is a common physiological fact.

Question 35. What is the life span of platelets?
Answer: The life span of platelets is approximately 10 days. After this period, old platelets are removed from the blood, and new ones are continuously produced to ensure proper clotting function.
In simple words: Platelets, which help stop bleeding, live for about 10 days.

🎯 Exam Tip: Recall that platelets have a relatively short lifespan compared to red blood cells, necessitating continuous production.

Question 36. What is the name of blood vessels which carry deoxygenated blood?
Answer: Veins are the blood vessels that typically carry deoxygenated blood back to the heart. There is one important exception: the pulmonary veins carry oxygenated blood from the lungs to the heart. However, in general, veins transport blood depleted of oxygen.
In simple words: Veins are the blood vessels that carry blood without much oxygen back to the heart.

🎯 Exam Tip: While veins generally carry deoxygenated blood, always remember the pulmonary veins as a key exception, carrying oxygenated blood from lungs to heart.

Question 37. What is pericardium?
Answer: The pericardium is a double-membranous covering that surrounds the heart. It protects the heart, keeps it in place within the chest, and prevents overfilling with blood. This protective sac also reduces friction during heartbeats.
In simple words: The pericardium is a two-layered sac that covers and protects the heart.

🎯 Exam Tip: Define pericardium as a protective sac around the heart, highlighting its double-layered structure.

Question 38. What is the function of major vein?
Answer: Major veins, such as the vena cava, bring deoxygenated blood from various systemic veins throughout the body back to the heart. They are essential for completing the circulatory loop by returning blood for re-oxygenation. They act as collecting channels for blood from different body parts.
In simple words: Big veins collect blood from all over the body and send it back to the heart.

🎯 Exam Tip: Focus on the primary role of major veins: collecting deoxygenated blood from the body and returning it to the heart.

Question 39. The process of excretion of ammonia is known by which name?
Answer: The process of excreting ammonia is known as ammonotelic excretion, and animals that primarily excrete ammonia are called ammonotelic. Ammonia is highly toxic and requires a large amount of water for its removal. This process is common in aquatic animals.
In simple words: When an animal gets rid of ammonia as waste, it's called ammonotelic excretion.

🎯 Exam Tip: Connect "ammonotelic" directly to the excretion of ammonia, often seen in aquatic organisms due to its high toxicity and water requirement.

Question 40. Which is the main excretory organ in humans?
Answer: The main excretory organs in humans are the kidneys. They filter blood to remove waste products and excess water, forming urine. The kidneys play a vital role in maintaining the body's fluid and electrolyte balance.
In simple words: Kidneys are the main organs that remove waste from the body in humans.

🎯 Exam Tip: Identify kidneys as the primary excretory organs and mention their role in filtering blood to form urine.

Question 42. Which is the main sex hormone in women?
Answer: Estrogen is the main sex hormone in women. It is responsible for the development of female secondary sexual characteristics and regulates the menstrual cycle. Estrogen also plays a role in bone health.
In simple words: Estrogen is the main female sex hormone.

🎯 Exam Tip: Remember estrogen as the primary female sex hormone, crucial for reproductive and secondary sexual characteristics.

Question 43. Where does implantation of placenta take place in mother?
Answer: Implantation of the placenta takes place in the endometrium. The endometrium is the inner lining of the uterus where the embryo attaches and develops. It provides nourishment to the growing fetus.
In simple words: The placenta attaches to the endometrium, which is the inner wall of the uterus.

🎯 Exam Tip: Clearly state "endometrium" (uterine lining) as the site of implantation for the placenta.

Question 44. Which system is responsible for coordination among various organs?
Answer: The nervous system and the endocrine system are responsible for coordination among various organs. The nervous system uses fast electrical signals, while the endocrine system uses slower chemical signals (hormones) to regulate body functions. Together, they ensure the body works as a coordinated unit.
In simple words: The nervous system and the endocrine system work together to make sure all body parts communicate and function smoothly.

🎯 Exam Tip: Recognize both the nervous system (electrical, fast) and endocrine system (chemical, slow) as key coordinators of bodily functions.

Question 45. Grey matter is present in which organ?
Answer: Grey matter is primarily present in the brain. It contains neuronal cell bodies, dendrites, and unmyelinated axons, and is involved in processing information. It is crucial for thought, memory, and movement.
In simple words: Grey matter is found mostly in the brain.

🎯 Exam Tip: Understand that grey matter is where much of the brain's processing occurs, contrasting with white matter which primarily transmits signals.

Question 46. Write the name of a neurotransmitter.
Answer: Acetylcholine is a common neurotransmitter. Neurotransmitters are chemical messengers that transmit signals across a chemical synapse, from one neuron to another "target" cell. Acetylcholine plays a crucial role in muscle contraction and memory.
In simple words: Acetylcholine is a chemical that helps nerve cells send messages to each other.

🎯 Exam Tip: Provide a specific example of a neurotransmitter like Acetylcholine and briefly state its role in nerve communication.

Question 47. Which hormone is produced by thyroid gland?
Answer: Thyroxin is the main hormone produced by the thyroid gland. Thyroxin plays a crucial role in regulating the body's metabolism, growth, and development. It helps convert food into energy.
In simple words: The thyroid gland makes a hormone called thyroxin.

🎯 Exam Tip: Connect the thyroid gland to thyroxin and its essential function in metabolic regulation.

Question 48. Adrenalin hormone is secreted by which gland?
Answer: Adrenalin hormone is secreted by the adrenal glands. Adrenal glands are located on top of the kidneys. Adrenalin, also known as epinephrine, is responsible for the "fight or flight" response, preparing the body for stressful situations.
In simple words: The adrenal gland makes adrenalin hormone.

🎯 Exam Tip: Remember that adrenal glands secrete adrenalin, a key hormone for the body's stress response.

Question 49. Which hormones are secreted by ovaries?
Answer: The ovaries secrete two main hormones: progesterone and estrogen. These hormones are vital for female reproductive health, including regulating the menstrual cycle and supporting pregnancy. They also contribute to the development of female secondary sexual characteristics.
In simple words: Ovaries make two hormones: progesterone and estrogen.

🎯 Exam Tip: Identify estrogen and progesterone as the primary hormones produced by the ovaries, crucial for female reproductive functions.

Question 50. Which hormone prepares the body for stress conditions?
Answer: Adrenaline is the hormone that prepares the body for stress conditions. It increases heart rate, blood pressure, and energy supply, enabling a "fight or flight" response. This helps the body react quickly to danger.
In simple words: Adrenaline hormone gets the body ready to face stressful situations.

🎯 Exam Tip: Recall adrenaline's role in the "fight or flight" response, which is the body's quick reaction to stress or danger.

Human System Short Answer Type Questions

Question 1. What is digestion? What is the need for digestion?
Answer: Digestion is the process of converting complex food nutrients into simple, soluble, and absorbable substances. This transformation is necessary because the food components we eat are too large and complex for our bodies to use directly. Through digestion, these large molecules are broken down into smaller ones that can be absorbed into the bloodstream and used for energy, growth, and cellular repair. Without digestion, our body cannot get the essential nutrients it needs from food.
In simple words: Digestion breaks down big food particles into tiny ones so our body can soak them up and use them for energy and growth. We need it because our body cannot use food directly in its complex form.

🎯 Exam Tip: Define digestion and clearly state the "need" for it: to convert complex food into usable, absorbable forms for energy and body functions.

Question 2. What are the main parts of alimentary canal?
Answer: The main parts of the alimentary canal include the mouth, pharynx, oesophagus, stomach, small intestine, large intestine, and rectum. This long tube-like structure is where all the food travels and gets processed. Each part has a specific role in breaking down food and absorbing nutrients.
In simple words: The main parts of the alimentary canal are the mouth, pharynx, food pipe, stomach, small intestine, large intestine, and rectum.

🎯 Exam Tip: List the parts of the alimentary canal in sequential order to show the path food takes during digestion.

Question 3. Name different types of salivary gland.
Answer: There are three main types of salivary glands: the parotid gland, submandibular gland, and sublingual gland. The parotid glands are located near the cheeks. The submandibular glands are found near the jaw. The sublingual glands are situated under the tongue. These glands produce saliva, which helps with digestion and keeps the mouth moist.
In simple words: The three types of salivary glands are parotid, submandibular, and sublingual glands.

🎯 Exam Tip: Memorize the names of the three major pairs of salivary glands and their general locations in the oral cavity.

Question 4. Stomach can be divided into three parts which are as follows:
• Cardia: This part is at the left and is connected to the oesophagus.
• Fundus: This part lies between cardia and pylorus.
• Pylorus: This part opens into small intestine.
Answer: The stomach is divided into three distinct regions: the cardia, the fundus, and the pylorus. The cardia is the entrance point from the oesophagus. The fundus is the dome-shaped upper part. The pylorus is the lower section that connects to the small intestine. Each region has specific functions related to food storage and digestion.
In simple words: The stomach has three parts: Cardia (top, connected to food pipe), Fundus (middle), and Pylorus (bottom, connected to small intestine).

🎯 Exam Tip: Remember the three named regions of the stomach and their anatomical sequence for proper description.

Question 5. Briefly explain the main parts of small intestine.
Answer: The small intestine is divided into three main portions: the duodenum, the jejunum, and the ileum. The duodenum is the first, shortest part, where most chemical digestion happens. The jejunum is the middle section, responsible for absorbing most nutrients. The ileum is the final and longest part, where the remaining nutrients, like vitamin B12 and bile salts, are absorbed before passing to the large intestine. The entire small intestine is where most digestion and absorption occur.
In simple words: The small intestine has three parts: duodenum (first part for digestion), jejunum (middle part for absorbing food), and ileum (last part for absorbing remaining nutrients).

🎯 Exam Tip: List the three parts of the small intestine in order (duodenum, jejunum, ileum) and briefly state the main function of each.

Question 6. Briefly explain the main parts in which colon of large intestine can be divided.
Answer: The colon, a major part of the large intestine, can be divided into four main sections: the ascending colon, transverse colon, descending colon, and sigmoid colon. The ascending colon moves upwards, the transverse colon goes across, the descending colon moves downwards, and the sigmoid colon is an S-shaped section leading to the rectum. These parts help absorb water and electrolytes, and form stool.
In simple words: The colon has four parts: ascending, transverse, descending, and sigmoid. They all help to take water out of digested food.

🎯 Exam Tip: Recall the four distinct sections of the colon, which are essential for water absorption and waste solidification.

Question 7. The main parts of the digestive system are as follows:
1. Buccal cavity opens outside through the mouth. It has the tongue, teeth and the opening of the salivary gland.
2. Buccal cavity leads to oesophagus.
3. The oesophagus opens into the stomach. The wall of the stomach contains gastric glands.
4. The stomach opens into the duodenum. This opening is regulated by a sphincter muscle which releases small amount of food at a time.
5. The duodenum receives the secretions of the liver and the pancreas.
6. From the duodenum, the food passes into the small intestine. The inner wall of the small intestine has a number of finger like projections called villi. The villi increases the surface area and are richly supplied with blood vessels.
7. The small intestine opens into the large intestine.
8. The terminal portion of the large intestine is called the rectum that opens out through the anus.
Answer: This question appears to be a duplicate of Question 2 (Main parts of alimentary canal) or related to Question 65 (Human digestive system explanation) on page 14, but with a different numbering scheme. The provided answer outlines the sequential path of food through the alimentary canal and the key structures involved in digestion and absorption. It explains how food is processed from the mouth to the anus, detailing the roles of various organs like the stomach, small intestine, and their connections. This comprehensive journey ensures all nutrients are extracted and waste is prepared for removal. The small intestine's villi, for example, are crucial for maximizing nutrient absorption.
In simple words: The digestive system starts with the mouth, then food goes through the pharynx, food pipe, stomach, small intestine, and large intestine, ending at the rectum and anus. Each part helps break down food and take in nutrients.

🎯 Exam Tip: Understand the complete journey of food through the alimentary canal, noting the specific functions and connections of each organ.

Question 8. Explain the digestion of food in mouth.
Answer: Digestion begins in the mouth with a process called mastication, where food is chewed and broken into smaller pieces. Saliva, containing mucus and the enzyme ptyalin (salivary amylase), mixes with the food. The mucus helps bind the food particles together, making them easier to swallow. Ptyalin starts the chemical digestion of starch, converting about 30% of it into maltose in the buccal cavity. This initial breakdown prepares the food for further digestion in the stomach. The mechanical breaking and chemical enzyme action work together.
In simple words: In the mouth, we chew food into small bits. Saliva mixes with it, and an enzyme in saliva starts breaking down starch.

🎯 Exam Tip: Focus on both mechanical (mastication) and chemical (ptyalin/salivary amylase for starch) digestion occurring in the mouth.

Question 9. Explain the digestion of food in stomach.
Answer: The stomach secretes three key digestive juices: mucus, proenzyme pepsinogen, and hydrochloric acid. Mucus protects the stomach lining, while hydrochloric acid, secreted by oxyntic cells, kills germs and creates an acidic environment. This acidity is essential for the pepsinogen to convert into active pepsin, an enzyme that starts protein digestion by breaking proteins into peptides. In young children, rennin is also secreted to help digest milk proteins. The stomach's churning also mechanically breaks down food further.
In simple words: In the stomach, acid kills germs, and enzymes start breaking down proteins. Mucus protects the stomach walls from the acid.

🎯 Exam Tip: Key points for stomach digestion are hydrochloric acid (germs, acidic environment), pepsin (protein digestion), and mucus (protection).

Question 10. Write a short note on exchange of gases in lungs.
Answer: Gas exchange primarily occurs in the alveoli of the lungs. The walls of the alveoli are very thin and surrounded by tiny blood vessels called capillaries. Due to differences in pressure, oxygen from the inhaled air in the alveoli moves into the blood, while carbon dioxide from the blood moves into the alveoli to be exhaled. This process is highly efficient because of the vast surface area and thin membranes involved. The alveoli are well adapted for this crucial function.
In simple words: In the lungs, tiny air sacs called alveoli swap gases: oxygen goes into the blood, and carbon dioxide leaves the blood to be breathed out.

🎯 Exam Tip: Mention alveoli and capillaries, and explain the concept of pressure difference driving the exchange of oxygen and carbon dioxide.

Question 11. Write a short note on RBCs.
Answer: Red Blood Cells (RBCs) make up about 99% of all blood cells. They contain a protein called hemoglobin, which gives blood its red color and binds to oxygen for transport throughout the body. RBCs are unique because they lack a nucleus, which allows them to carry more oxygen. Their lifespan is about 120 days, after which they are replaced by new cells produced in the bone marrow. Their biconcave shape also helps them carry more oxygen and move through blood vessels easily.
In simple words: RBCs are red blood cells that have hemoglobin, which carries oxygen and gives blood its color. They live for about 120 days.

🎯 Exam Tip: Include key characteristics: 99% of blood cells, contain hemoglobin, lack a nucleus, and have a 120-day lifespan, all linked to oxygen transport.

Question 12. What do you understand by types of blood?
Answer: Blood is classified into four main types—A, B, AB, and O—based on the presence or absence of specific antigens (A or B) on the surface of red blood cells. Blood group A has A antigens, group B has B antigens, group AB has both A and B antigens, and group O has neither. These antigens are crucial for safe blood transfusions, as incompatible blood types can cause severe reactions. This classification system is known as the ABO blood group system.
In simple words: Blood types (A, B, AB, O) are decided by certain markers called antigens on red blood cells, which are important for safe blood transfusions.

🎯 Exam Tip: Clearly state the four main blood types (A, B, AB, O) and explain their basis on the presence or absence of A and B antigens.

Question 13. What is double circulation? What is the benefit of double circulation?
Answer: Double circulation means that blood passes through the heart twice in one complete circuit of the body. First, deoxygenated blood goes from the heart to the lungs for oxygenation (pulmonary circulation). Then, oxygenated blood returns to the heart and is pumped to the rest of the body (systemic circulation). The main benefit is that it ensures complete separation of oxygenated and deoxygenated blood, leading to a highly efficient supply of oxygen to the body's tissues. This is crucial for warm-blooded animals like mammals and birds, which need a lot of energy to maintain their body temperature and activity levels. Efficient oxygen delivery supports higher metabolic rates.
In simple words: Double circulation means blood goes through the heart two times in one round trip, keeping oxygen-rich and oxygen-poor blood separate. This helps our bodies get a lot of oxygen efficiently.

🎯 Exam Tip: Define double circulation by explaining pulmonary and systemic circuits, and emphasize "efficient oxygen supply" as its primary benefit, especially for warm-blooded animals.

Question 14. What is excretion? What is the need for excretion?
Answer: Excretion is the process of removing metabolic waste products from the body. During various metabolic activities, cells produce substances like urea, uric acid, and ammonia, which can be harmful or toxic if they accumulate. The body needs to excrete these wastes to maintain internal balance (homeostasis) and prevent poisoning. For example, the kidneys filter blood to remove urea, which is then expelled as urine. This continuous removal ensures that our body functions properly and stays healthy.
In simple words: Excretion is how our body gets rid of harmful waste made during daily activities. We need it to stay healthy and stop bad substances from building up.

🎯 Exam Tip: Clearly define excretion as waste removal and explain its necessity for maintaining homeostasis and preventing toxicity in the body.

Question 15. Explain the structure of a nephron.
Answer: A nephron is the functional unit of the kidney, responsible for filtering blood and forming urine. Each nephron consists of a renal corpuscle and a renal tubule. The renal corpuscle includes a cup-shaped structure called Bowman's capsule, which encloses a cluster of tiny blood vessels called the glomerulus. The glomerulus acts as the primary filter, pushing fluid and small solutes into the Bowman's capsule. The renal tubule, extending from the capsule, is a highly convoluted tube divided into the proximal convoluted tubule, loop of Henle, and distal convoluted tubule. This tubule performs reabsorption and secretion, modifying the filtrate into urine, which then drains into collecting ducts. The specialized structure allows efficient filtration and reabsorption.
In simple words: A nephron is the tiny part of the kidney that cleans blood. It has a Bowman's capsule with a glomerulus for filtering, and a long tube that takes out useful things and leaves waste to become urine.

🎯 Exam Tip: Describe the nephron by its two main parts (renal corpuscle and renal tubule) and their sub-components, emphasizing their roles in filtration, reabsorption, and secretion.

Question 16. What are the changes which take place in adolescent boys?
Answer: During adolescence, boys undergo several physical changes due to hormonal shifts. Their shoulders become broader, and the body generally becomes more muscular. There is also an increase in height and weight, the voice deepens, and hair grows on the face, chest, and armpits. These changes are driven by testosterone and prepare the body for reproductive maturity. The growth spurt is very noticeable during this period.
In simple words: Adolescent boys get broader shoulders and more muscles. They also grow taller, their voice gets deeper, and hair grows on their face and body.

🎯 Exam Tip: List key secondary sexual characteristics that develop in adolescent boys, such as broader shoulders, muscularity, voice deepening, and hair growth.

Question 63. What is the role of hypothalamus in endocrine system?
Answer: The hypothalamus plays a crucial role in the endocrine system by controlling the release of hormones from the pituitary gland. It produces two types of hormones: releasing hormones and inhibitory hormones. Releasing hormones stimulate the pituitary gland to secrete its own hormones, while inhibitory hormones prevent the pituitary from releasing certain hormones. This regulatory function makes the hypothalamus a key link between the nervous system and the endocrine system, ensuring proper hormonal balance throughout the body. It is often called the "control center" of the endocrine system.
In simple words: The hypothalamus controls the pituitary gland by sending out hormones that either make it release more hormones or stop it from releasing hormones. It is like the boss of the hormone system.

🎯 Exam Tip: Explain that the hypothalamus acts as the bridge between the nervous and endocrine systems, controlling the pituitary gland via releasing and inhibitory hormones.

Question 64. Explain the endocrine and exocrine functions of pancreas.
Answer: The pancreas is a unique organ with both endocrine and exocrine functions. Its endocrine function involves secreting hormones directly into the bloodstream, primarily insulin and glucagon. Insulin lowers blood sugar by helping cells absorb glucose, while glucagon raises blood sugar by signaling the liver to release stored glucose. These hormones are vital for regulating blood sugar levels. Its exocrine function involves producing digestive enzymes that are released into the small intestine. These enzymes include amylase (for carbohydrates), trypsin and chymotrypsin (for proteins), and lipase (for fats), which break down food components. Thus, the pancreas balances both blood sugar and food digestion. The islets of Langerhans are the endocrine part, while acinar cells handle the exocrine part.
In simple words: The pancreas has two jobs: Endocrine function is making insulin and glucagon to control blood sugar. Exocrine function is making enzymes to digest food like carbs, proteins, and fats.

🎯 Exam Tip: Clearly differentiate between the endocrine role (insulin, glucagon, blood sugar regulation) and exocrine role (digestive enzymes for food breakdown) of the pancreas.

Human System Long Answer Type Questions

Question 65. Explain the human digestive system. Explain the significance of enzymes which are involved in digestion.
Answer: The human digestive system is a long, winding alimentary canal, about 8 to 10 meters long, along with several accessory glands and organs. It starts from the mouth and ends at the anus.
Mouth: The alimentary canal begins with the mouth, a bowl-shaped buccal cavity lined by a soft palate at the bottom and a hard palate at the top. Here, food is chewed and mixed with saliva.
Pharynx: From the buccal cavity, food moves into the pharynx, which acts as a passageway for both food and air.
Oesophagus: Food then enters the oesophagus. A flap called the epiglottis ensures food only enters the food pipe, not the windpipe. Mucus glands in the oesophagus make food slippery, and rhythmic contractions (peristalsis) push it down to the stomach.
Stomach: This J-shaped organ lies in the abdominal cavity, behind the diaphragm. It can hold up to three litres of food and is divided into cardia, fundus, and pylorus. The stomach churns food into a paste, kills germs with acid, and begins protein digestion.
Small Intestine: This is a highly coiled, 7-meter long tube starting from the pylorus. It's the most important part of the alimentary canal for digestion and absorption. It's divided into three parts: duodenum, jejunum, and ileum. The inner walls have finger-like projections called villi, which greatly increase the surface area for nutrient absorption into the blood. The small intestine is where most nutrients are finally absorbed into the bloodstream.
Significance of Enzymes: Enzymes are vital biological catalysts produced in the digestive system. They are hydrolytic enzymes that speed up the breakdown of complex food molecules into simpler substances. For example, amylase breaks down carbohydrates, pepsin and trypsin break down proteins, and lipase breaks down fats. Without these enzymes, digestion would be too slow to provide the body with the necessary nutrients for survival. They make it possible to efficiently extract energy and building blocks from food. Enzymes are specific to the type of molecule they break down, ensuring complete digestion.
In simple words: The human digestive system is a long tube from mouth to anus, with organs like the stomach and small intestine breaking down food. Enzymes are like special helpers that speed up this breakdown so our body can get all the nutrients it needs.

🎯 Exam Tip: When explaining the digestive system, list the organs in order and describe their main function. For enzymes, emphasize their role as catalysts for breaking down complex food molecules efficiently.

Question 66. Explain the significance of trachea, bronchioles, lungs and respiratory muscles in human respiratory system.
Answer: Each part of the respiratory system plays a vital role in breathing. Trachea: The trachea is made of rings of cartilage that prevent it from collapsing. This ensures that the air passage always stays open. Bronchioles: These are smaller tubes that carry air into the two lungs. Lungs: The lungs are very flexible organs that can expand to hold a large amount of air. Respiratory Muscles: The diaphragm and intercostal muscles are key respiratory muscles. They create a negative pressure inside the lungs, which helps to draw air in from the outside. These muscles also help to change the width of the rib cage during breathing. In simple words: The trachea keeps the air pipe open, bronchioles take air to the lungs, lungs expand for air, and special muscles (diaphragm and intercostal muscles) help pull air in by changing chest pressure. Each part works together for breathing.

🎯 Exam Tip: When explaining the significance of organs, always mention their structural features (like cartilaginous rings for trachea) and how these features enable their function.

Plasma

Plasma makes up about 55% of the total blood volume. Around 92% of plasma is water, and the rest consists of organic and inorganic substances.

Red Blood Cells or Red Blood Corpuscles (RBCs)

RBCs form 99% of all blood cells. They contain a protein called hemoglobin, which gives blood its red color. RBCs do not have a nucleus and live for about 120 days.

White Blood Cells or White Blood Corpuscles (WBCs)

WBCs are colorless because they do not have hemoglobin. They help the body's immune system fight off diseases. WBCs are made in the bone marrow and are of two types: granulocytes and agranulocytes.

• Granulocytes: Neutrophils, eosinophils, and basophils are types of granulocytes. Neutrophils are the most common type.
• Agranulocytes: Lymphocytes and monocytes are types of agranulocytes. Lymphocytes are divided into three kinds: B-lymphocytes, T-lymphocytes, and natural killer cells. Lymphocytes help protect the body from diseases. Monocytes become macrophages once they mature. Neutrophils, lymphocytes, and macrophages are important cells that defend the body by engulfing foreign invaders.

Platelets

Platelets are also known as thrombocytes. There are about 3 lakh platelets per cubic millimeter of blood. Platelets live for about 10 days and are essential for blood clotting.

Importance of Blood

• Blood carries various substances throughout the body.
• It helps regulate body temperature.
• It keeps the body's pH level balanced.
• It plays a key role in the immune system.

Question 68. Analyse urine formation in humans. Explain the structure of kidneys.
Answer: Urine formation happens in three main steps: glomerular filtration, reabsorption, and collection.

• Glomerular Filtration: Blood flows into a network of tiny blood vessels called the glomerulus, which is inside Bowman's capsule. Due to a difference in pressure, water and dissolved waste products are forced out of the blood and into the capsule.
• Reabsorption: The liquid filtered from the glomerulus then moves through a long tube. During this passage, the body selectively reabsorbs most of the useful substances like water, glucose, and amino acids back into the bloodstream. This helps the body conserve important nutrients and water.
• Collection: After reabsorption, the remaining liquid, which is now urine, contains mostly dissolved nitrogenous wastes like urea. This urine is then sent to a collecting duct and eventually stored in the urinary bladder before being excreted.

Structure of Kidney: Each kidney is shaped like a bean and has a dark brown color. There is a dip in the middle called the hylum, which is where blood vessels and nerves enter and exit. Inside the hylum, there is a funnel-shaped area called the pelvis. The outer part of the kidney is called the cortex, and the inner part is called the medulla. Each kidney contains many tiny filtering units called nephrons. In simple words: Urine is made in three steps: first, blood is filtered in the glomerulus; then, useful things are reabsorbed back into the body; finally, the waste liquid is collected as urine. Kidneys are bean-shaped organs with outer (cortex) and inner (medulla) parts, and they have tiny filters called nephrons.

🎯 Exam Tip: Remember the three main steps of urine formation and describe each briefly. For kidney structure, focus on key terms like hylum, cortex, medulla, and nephrons.

Question 69. Make a diagram of male reproductive system and explain the function of primary reproductive organs in humans.
Answer: The primary reproductive organs in males include the testes, vas deferens, seminal vesicles, and prostate gland. The testes are responsible for producing sperm. The vas deferens acts as a tube that transports sperm to the seminal vesicles. The prostate gland releases fluids that combine with sperm in the seminal vesicle to form semen.

The primary reproductive organs in females include the ovaries, fallopian tubes, uterus, and vagina. The ovaries produce eggs. During ovulation, the fallopian tubes receive an egg. Fertilization, where the sperm and egg meet, typically occurs in the fallopian tube. The uterus is the place where a fertilized egg implants and develops into an embryo. The vagina serves as a passage for semen during intercourse and as the birth canal during childbirth. In simple words: The male system includes testes (make sperm), vas deferens, seminal vesicles, and prostate gland (form semen). The female system has ovaries (make eggs), fallopian tubes (where fertilization happens), uterus (where the baby grows), and vagina (birth canal). The source typically shows diagrams of these systems.

🎯 Exam Tip: For reproductive systems, always clearly state the main organs and their primary functions. Highlighting the location of sperm/egg production and fertilization is crucial.

Peripheral Nervous System

This system consists of peripheral nerves and is divided into two main parts:

• Somatic Nervous System
• Autonomous Nervous System

Importance of Hypothalamus

The hypothalamus manages the release of hormones from the pituitary gland. It also plays a role in controlling feelings of hunger and thirst.

Importance of Pituitary Gland

The pituitary gland releases growth hormone, which controls how the body grows. The hormones from the pituitary gland also regulate the secretions of other glands in the body.

Human System Additional Questions Solved

I. Multiple Choice Questions

Question 1. Which of the following controls the movement of food, digested food and waste materials?
(a) Sphincters
(b) Mucosa
(c) Submucus Layer
(d) Both (b) and (c)
Answer: (a) Sphincters
In simple words: Sphincters are ring-shaped muscles that act like valves. They open and close to control the flow of food, digested food, and waste through the body's tubes, ensuring movement in one direction.

🎯 Exam Tip: Remember that sphincters are essential muscles that regulate the passage of substances and prevent backflow in various bodily systems.

Question 2. How many teeth are present in each jaw in a normal adult?
(a) 8
(b) 16
(c) 24
(d) 32
Answer: (b) 16
In simple words: In a healthy adult, each jaw (upper and lower) has 16 teeth, making a total of 32 teeth in the entire mouth.

🎯 Exam Tip: Knowing the number of teeth in each jaw helps understand the complete adult dental formula, which includes incisors, canines, premolars, and molars.

Question 3. Human beings get how many sets of teeth in their lifetime?
(a) One
(b) Two
(c) Four
(d) Many
Answer: (b) Two
In simple words: Humans have two sets of teeth during their life: the first set is temporary (baby teeth), and the second set is permanent (adult teeth).

🎯 Exam Tip: The two sets of teeth (deciduous and permanent) reflect the changing nutritional and structural needs from childhood to adulthood.

Question 4. How many incisors are present in each jaw?
(a) One
(b) Two
(c) Four
(d) Eight
Answer: (c) Four
In simple words: Each jaw (upper and lower) in humans has four incisor teeth. These are the front, flat teeth used for biting food.

🎯 Exam Tip: Incisors are cutting teeth at the front of the mouth, crucial for the initial processing of food. Remember there are four in both the upper and lower jaws.

Question 6. Which part of stomach is connected to oesophagus?
(a) Cardia
(b) Fundus
(c) Pylorus
(d) All of the options
Answer: (a) Cardia
In simple words: The top part of the stomach, where the food pipe (oesophagus) connects, is called the cardia.

🎯 Exam Tip: The cardia is the entry point for food into the stomach and contains the cardiac sphincter, which prevents reflux of stomach contents.

Question 7. Which part of stomach is connected to small intestine?
(a) Cardia
(b) Fundus
(c) Pylorus
(d) None of the options
Answer: (c) Pylorus
In simple words: The pylorus is the lowest part of the stomach that connects to the small intestine. It controls how food leaves the stomach.

🎯 Exam Tip: The pyloric sphincter at this junction regulates the precise release of chyme (partially digested food) into the duodenum, which is essential for efficient digestion.

Question 8. Digestion takes place in which part of small intestine?
(a) Duodenum
(b) Jejunum
(c) Ileum
(d) All of the options
Answer: (a) Duodenum
In simple words: The duodenum is the very first section of the small intestine where most of the chemical digestion of food occurs with the help of enzymes.

🎯 Exam Tip: The duodenum is a critical site because it receives digestive juices from the pancreas and bile from the liver, initiating the breakdown of most nutrients.

Question 10. Digestion of protein is completed in which part of alimentary canal?
(a) Mouth
(b) Oesophagus
(c) Stomach
(d) Small intestine
Answer: (d) Small intestine
In simple words: Even though protein digestion starts in the stomach, it is fully finished in the small intestine, where proteins are broken down into amino acids.

🎯 Exam Tip: While the stomach initiates protein digestion with pepsin, remember that the small intestine, with enzymes like trypsin and chymotrypsin, is responsible for its complete breakdown and absorption.

Question 11. Most of the absorption of digested food takes place in which of the following?
(a) Duodenum
(b) Jejunum
(c) Ileum
(d) Colon
Answer: (b) Jejunum
In simple words: The majority of digested food is absorbed into the bloodstream in the jejunum, which is the middle section of the small intestine.

🎯 Exam Tip: The jejunum's highly folded inner surface, lined with villi and microvilli, creates a vast area for efficient absorption of nutrients.

Question 12. Bile is produced by which gland?
(a) Salivary gland
(b) Pancreas
(c) Liver
(d) Thyroid gland
Answer: (c) Liver
In simple words: The liver is the organ that produces bile. Bile helps the body digest fats in the small intestine.

🎯 Exam Tip: While the liver produces bile, it is stored and concentrated in the gallbladder before being released when needed for fat emulsification.

Question 14. Dust particles from air are mainly filtered in which part of the respiratory system?
(a) Nasal chamber
(b) Pharynx
(c) Larynx
(d) Trachea
Answer: (a) Nasal chamber
In simple words: The nasal chamber, or nose, is the first place where air enters the respiratory system. It has hairs and mucus that trap dust and other small particles, cleaning the air.

🎯 Exam Tip: The nasal cavity's structure, with its cilia and mucus lining, is specifically designed for initial air filtration, warming, and humidification.

Question 15. Which of the following is also known as voice box?
(a) Nasal chamber
(b) Pharynx
(c) Larynx
(d) Trachea
Answer: (c) Larynx
In simple words: The larynx is commonly called the voice box. It contains vocal cords that vibrate to make sounds when air passes through them.

🎯 Exam Tip: The larynx is not only crucial for sound production but also acts as a gateway to the trachea, preventing food from entering the windpipe.

Question 16. Which of the following is made up of cartilaginous rings?
(a) Nasal chamber
(b) Pharynx
(c) Larynx
(d) Trachea
Answer: (d) Trachea
In simple words: The trachea, also known as the windpipe, is supported by C-shaped rings of cartilage. These rings keep the airway open and prevent it from collapsing.

🎯 Exam Tip: The cartilaginous rings are incomplete at the back, allowing the esophagus to expand slightly when swallowing food.

Question 19. Alveoli are lined with which type of epithelium?
(a) Squamous epithelium
(b) Stratified epithelium
(c) Ciliated epithelium
(d) Glandular epithelium
Answer: (a) Squamous epithelium
In simple words: The alveoli, which are tiny air sacs in the lungs, are lined with very thin, flat cells called squamous epithelium. This thin lining helps gases (like oxygen and carbon dioxide) pass through easily.

🎯 Exam Tip: The thinness of the squamous epithelium in alveoli is key to efficient gas exchange, as it minimizes the distance gases need to travel to enter or leave the bloodstream.

Question 20. In an adult, blood is produced in which organ?
(a) Lungs
(b) Bone marrow
(c) Spleen
(d) Lymph nodes
Answer: (b) Bone marrow
In simple words: In adults, new blood cells are continuously made in the bone marrow, which is found inside many bones.

🎯 Exam Tip: Bone marrow is the primary site of hematopoiesis (blood cell formation) in adults, producing red blood cells, white blood cells, and platelets.

Question 21. In neonates, blood is produced in which organ?
(a) Lungs
(b) Bone marrow
(c) Spleen
(d) Lymph nodes
Answer: (c) Spleen
In simple words: In very young babies (neonates), blood can be produced in organs like the spleen, in addition to the bone marrow.

🎯 Exam Tip: While bone marrow takes over as the primary site for blood production later, the spleen and liver can perform this function during fetal development and in neonates.

Question 22. What is lymph?
Answer: Lymph is a clear fluid that leaks out of blood capillaries into the spaces between cells. This fluid, which contains white blood cells and proteins, is then collected by lymphatic vessels and returned to the bloodstream. In simple words: Lymph is a clear liquid found in the body that helps clean tissues and carries immune cells. It is basically tissue fluid that drains back into the blood system.

🎯 Exam Tip: Understand lymph as an essential part of the immune system and fluid balance, distinct from blood but derived from it.

Question 23. WBCs are produced in which organ?
(a) Bone marrow
(b) Spleen
(c) Heart
(d) Lymph nodes
Answer: (a) Bone marrow
In simple words: White blood cells (WBCs) are made in the bone marrow, the soft tissue inside our bones.

🎯 Exam Tip: Bone marrow is the factory for all types of blood cells, including the immune-fighting white blood cells.

Question 24. Which of the following is responsible for coagulation of blood?
(a) RBCs
(b) WBCs
(c) Platelets
(d) Plasma
Answer: (c) Platelets
In simple words: Platelets are tiny cells in the blood that help it clot. When you get a cut, platelets rush to the area to stop the bleeding.

🎯 Exam Tip: Platelets initiate the clotting cascade, forming a plug that prevents excessive blood loss after injury. Their function is crucial for hemostasis.

Question 25. How many people in the world have Rh positive blood?
(a) 50%
(b) 60%
(c) 70%
(d) 80%
Answer: (d) 80%
In simple words: About 80 out of every 100 people around the world have Rh positive blood. This means their red blood cells have a specific protein called the Rh factor.

🎯 Exam Tip: Understanding Rh factor is important for blood transfusions and in pregnancy, where an Rh-negative mother carrying an Rh-positive baby might face complications.

Question 27. Which excretory product is removed by lungs?
(a) Urea
(b) Ammonia
(c) Carbon dioxide
(d) Uric acid
Answer: (c) Carbon dioxide
In simple words: Our lungs help us get rid of carbon dioxide, which is a waste gas produced by the body, through breathing out.

🎯 Exam Tip: Lungs primarily handle gaseous waste (carbon dioxide and some water vapor), while kidneys handle soluble nitrogenous wastes like urea.

Question 28. Excretory waste is filtered from blood in which of the following parts?
(a) Glomerulus
(b) Efferent arteriole
(c) Afferent arteriole
(d) Loop of Henle
Answer: (a) Glomerulus
In simple words: The glomerulus, a tiny network of blood vessels in the kidney, is where waste products are first filtered out of the blood.

🎯 Exam Tip: The glomerulus acts like a very fine sieve, allowing small molecules and waste to pass through while retaining blood cells and large proteins.

Question 29. What is the age for onset of puberty in girls?
(a) 9-10 years
(b) 12-14 years
(c) 16th year
(d) After 18 years
Answer: (b) 12 - 14 years
In simple words: Puberty, the time when a girl's body starts changing into an adult body, usually begins between 12 and 14 years of age.

🎯 Exam Tip: Puberty involves a series of hormonal and physical changes that lead to sexual maturity, with typical ranges but individual variations in onset.

Question 31. Sperms are produced in which organ?
(a) Testis
(b) Seminal vesicle
(c) Vas deferens
(d) Prostate gland
Answer: (a) Testis
In simple words: Sperms, which are male reproductive cells, are made in the testes.

🎯 Exam Tip: The testes are the primary male reproductive organs, responsible for both sperm production (spermatogenesis) and hormone synthesis.

Question 32. Eggs are produced by which organ?
(a) Ovary
(b) Fallopian tubes
(c) Uterus
(d) Cervix
Answer: (a) Ovary
In simple words: Eggs, which are female reproductive cells, are produced in the ovaries.

🎯 Exam Tip: The ovaries are the primary female reproductive organs, performing both ovum production (oogenesis) and hormone secretion (estrogen and progesterone).

Question 33. What is the gestation period in human beings?
(a) 10 weeks
(b) 20 weeks
(c) 40 weeks
(d) 60 weeks
Answer: (c) 40 weeks
In simple words: In humans, the gestation period, which is the time from conception to birth, is about 40 weeks or nine months.

🎯 Exam Tip: The gestation period is crucial for the complete development of the fetus and typically ranges from 37 to 42 weeks, with 40 weeks being the average.

Question 35. How many types of neurons are present in the body?
(a) One
(b) Two
(c) Three
(d) Four
Answer: (b) Two
In simple words: There are mainly two types of neurons (nerve cells) in the body: sensory neurons (carry signals to the brain) and motor neurons (carry signals from the brain). Some classifications also include interneurons.

🎯 Exam Tip: While often simplified to two main types, a more detailed classification includes three types: sensory, motor, and interneurons, each with distinct roles in nervous system communication.

Question 36. Involuntary functions are controlled by which part of the brain?
(a) Cerebrum
(b) Cerebellum
(c) Medulla
(d) Pons
Answer: (c) Medulla
In simple words: The medulla, a part of the brainstem, controls actions that we don't think about, like breathing, heart rate, and digestion.

🎯 Exam Tip: The medulla oblongata is a vital control center for many autonomic (involuntary) functions, essential for maintaining basic life processes.

Question 37. Which is the functional unit of nervous system?
(a) Brain
(b) Spinal cord
(c) Nerves
(d) Neurons
Answer: (d) Neurons
In simple words: Neurons, also called nerve cells, are the basic units of the nervous system. They carry electrical and chemical signals throughout the body.

🎯 Exam Tip: Neurons are specialized cells that transmit information through electrical impulses and chemical signals, forming the communication network of the nervous system.

Question 39. Which hormone prepares the body for stress conditions?
(a) Gonadaotropic hormone
(b) Melatonin
(c) Adrenalin
(d) Thyroxin
Answer: (c) Adrenalin
In simple words: Adrenalin, also known as epinephrine, is a hormone that gets the body ready to respond to stress, often called the "fight or flight" response.

🎯 Exam Tip: Adrenalin is secreted by the adrenal glands and plays a crucial role in immediate stress responses by increasing heart rate, blood pressure, and energy availability.

Question 40. Which gland is situated above kidneys?
(a) Pituitary gland
(b) Thyroid gland
(c) Adrenal gland
(d) Pancreas
Answer: (c) Adrenal gland
In simple words: The adrenal glands are small glands located on top of each kidney. They produce hormones like adrenalin.

🎯 Exam Tip: The adrenal glands consist of two parts, the cortex and the medulla, each producing different hormones vital for stress response, metabolism, and blood pressure regulation.

Human System Very Short Answer Type Questions

Question 1. What is digestion? What is the need for digestion?
Answer: Digestion is the process where complex nutrients are changed into simpler forms that can dissolve and be absorbed by the body. Food components are usually complex substances that the body cannot use directly. They need to be broken down into simpler parts so the body can take them in and use them. This is why digestion is needed. In simple words: Digestion is breaking down big food parts into small, usable pieces. Our body needs digestion because it cannot use food in its complex form; it must be broken down first.

🎯 Exam Tip: Emphasize that digestion's core purpose is to convert macromolecules into absorbable micromolecules, highlighting the unsuitability of complex food for direct bodily use.

Question 2. What do you understand by diphyodont?
Answer: Diphyodont refers to the characteristic of human beings having two sets of teeth during their lifetime. The first set is temporary (milk teeth), and these are later replaced by a permanent set of teeth. In simple words: Diphyodont means having two sets of teeth in a lifetime. Humans first get baby teeth, and then these are replaced by adult teeth.

🎯 Exam Tip: Knowing the term "diphyodont" helps describe the human dental pattern and its evolutionary advantages for growth and changing dietary needs.

Question 5. What is vermiform appendix?
Answer: The vermiform appendix is a small, finger-shaped organ. It is found where the small intestine meets the large intestine. It is considered a vestigial organ, meaning it has lost most of its original function over time.
In simple words: The appendix is a tiny organ at the start of the large intestine. It doesn't seem to have a big job in our body anymore.

🎯 Exam Tip: Remember that vestigial organs are parts of the body that were useful to ancestors but are not fully functional now.

Question 6. What is rennin?
Answer: Rennin is an enzyme that helps to digest milk protein. It is mostly found in the stomachs of young mammals, including human babies, to help them break down milk easily. This enzyme is very important for proper milk digestion in infants.
In simple words: Rennin is a special helper in the stomach that breaks down milk. Babies have a lot of it to digest milk.

🎯 Exam Tip: When defining enzymes, always state what they act upon (substrate) and what they help to do (function).

Question 7. Which enzyme is produced in stomach and digests protein?
Answer: Pepsin is the enzyme produced in the stomach that starts the digestion of proteins. It works best in the acidic environment created by hydrochloric acid in the stomach. Proteins are large molecules that need to be broken down into smaller pieces for the body to use.
In simple words: Pepsin is a stomach enzyme that breaks down proteins. It needs a lot of stomach acid to work well.

🎯 Exam Tip: Link enzymes to their specific site of production and the nutrient they digest for a complete answer.

Question 8. Which acid is produced in stomach?
Answer: The stomach produces hydrochloric acid. This acid creates a very strong acidic environment in the stomach, which helps in killing harmful bacteria present in food and also activates protein-digesting enzymes like pepsin. This acidic condition is crucial for proper digestion.
In simple words: Hydrochloric acid is made in the stomach. It helps kill germs and makes the stomach acidic for digestion.

🎯 Exam Tip: Mention both functions of hydrochloric acid: killing bacteria and activating enzymes.

Question 9. Large intestine is divided into how many parts?
Answer: The large intestine is typically divided into four main parts: the cecum, the colon, the rectum, and the anal canal. Each section plays a vital role in processing waste and absorbing water before elimination. However, specifically the colon, which is the longest part, is often divided into four sections.
In simple words: The large intestine has four main parts. These parts help remove waste from the body.

🎯 Exam Tip: While the large intestine has four general parts, sometimes questions refer to the four sections of the colon specifically (ascending, transverse, descending, sigmoid).

Question 10. Which gland produces most of the digestive enzymes?
Answer: The pancreas produces most of the digestive enzymes. It creates a wide range of enzymes, including amylase for carbohydrates, trypsin for proteins, and lipase for fats. These enzymes are sent to the small intestine to complete the digestion of food. Without the pancreas, digestion would be very difficult.
In simple words: The pancreas makes many different enzymes to help digest food. These enzymes break down carbs, proteins, and fats.

🎯 Exam Tip: The pancreas is a dual-function gland (endocrine and exocrine); focus on its exocrine role for digestive enzymes.

Question 12. Bile is stored in which organ?
Answer: Bile, which is produced by the liver, is stored in the gall bladder. The gall bladder concentrates the bile and releases it into the small intestine when fatty food is present. This helps in breaking down fats into smaller droplets for easier digestion.
In simple words: Bile is made by the liver but kept in the gall bladder. It helps digest fats in our food.

🎯 Exam Tip: Clearly differentiate between where bile is produced (liver) and where it is stored and concentrated (gall bladder).

Question 13. Fat is digested by which enzyme?
Answer: Fat is digested by an enzyme called lipase. Lipase breaks down large fat molecules into smaller fatty acids and glycerol, which the body can then absorb. This enzyme is mainly produced in the pancreas and also in the small intestine.
In simple words: Lipase is the enzyme that breaks down fats. It turns fats into tinier pieces for the body to take in.

🎯 Exam Tip: Remember the "-ase" suffix for enzymes often indicates the substance they act upon (e.g., lipase for lipids/fats).

Question 14. After respiration, energy is stored in which form?
Answer: After respiration, energy is stored in the form of ATP (Adenosine Triphosphate). ATP is like the energy currency of the cell, providing energy for various cellular processes and activities. When a cell needs energy, it breaks down ATP. This energy helps your body do everything from thinking to moving.
In simple words: Energy from breathing is saved as ATP. ATP is like tiny energy packets for our body's cells to use.

🎯 Exam Tip: Know the full form of ATP and its role as the immediate energy source for cellular activities.

Question 15. What is the role of mouth in respiration?
Answer: The mouth plays a secondary role in respiration. It can act as an alternative air passage when the nasal passage is blocked, for example, due to a cold. However, breathing through the nose is generally preferred as it filters, warms, and moistens the air. The mouth also helps with deeper breaths during intense exercise.
In simple words: The mouth helps us breathe if our nose is blocked. It's a backup breathing path, not the main one.

🎯 Exam Tip: Emphasize that the mouth is a secondary pathway and briefly explain why nasal breathing is better.

Question 16. Which respiratory muscle is present at the floor of thoracic cavity?
Answer: The diaphragm is the main respiratory muscle located at the floor of the thoracic cavity, beneath the lungs. It contracts and flattens during inhalation, increasing the volume of the chest cavity and drawing air into the lungs. This muscle is essential for normal breathing.
In simple words: The diaphragm is a muscle below our lungs. It moves down to help us breathe air in.

🎯 Exam Tip: Remember the diaphragm's location and its primary action (contraction during inhalation) in breathing.

Question 17. Diaphragm is made up of which type of muscle?
Answer: The diaphragm is primarily made up of skeletal muscle. Skeletal muscles are voluntary, meaning we can control their movement, but the diaphragm also functions automatically. This dual control ensures continuous breathing even when we are not actively thinking about it. These muscles are attached to bones and help with movement.
In simple words: The diaphragm is made of skeletal muscle. We can choose to control it, but it also works on its own to help us breathe.

🎯 Exam Tip: Note that while it's skeletal muscle, its automatic function highlights an important physiological adaptation.

Question 19. Which substance imparts red color to blood?
Answer: Haemoglobin is the substance that gives blood its red color. It is a protein found in red blood cells that contains iron, which binds to oxygen. The bright red color is due to oxygen-rich haemoglobin, while deoxygenated blood is a darker red. This protein is vital for carrying oxygen throughout the body.
In simple words: Haemoglobin makes blood red. It is a protein in red blood cells that carries oxygen.

🎯 Exam Tip: Connect haemoglobin's red color directly to its iron content and oxygen-binding function.

Question 20. What is the function of macrophages?
Answer: Macrophages are a type of white blood cell that play a crucial role in the immune system. Their main function is to "eat away" antigens, which are harmful substances like bacteria, viruses, and dead cells. They do this through a process called phagocytosis, cleaning up debris and protecting the body from infections. They are like the body's clean-up crew.
In simple words: Macrophages are immune cells that eat harmful germs and dead cells. They keep our body clean and safe.

🎯 Exam Tip: Use terms like "phagocytosis" and "antigens" when describing macrophage function for higher accuracy.

Question 21. Which antigen is present in RBCs of blood group AB?
Answer: Individuals with blood group AB have both Antigen A and Antigen B present on the surface of their red blood cells. This unique combination makes them "universal recipients" in blood transfusions, as they can receive blood from any ABO blood group. The presence of both antigens is what defines the AB blood type.
In simple words: Blood group AB has both A and B antigens on its red blood cells. This means it can get blood from all other groups.

🎯 Exam Tip: Remember that blood type is determined by the specific antigens present on red blood cells.

Question 22. What is lymph?
Answer: Lymph is the interstitial fluid that is drained back into circulation by the lymphatic system. It is a clear fluid that contains white blood cells and plays a vital role in immunity, transporting immune cells and clearing waste products from tissues. Lymph is essentially tissue fluid that has entered the lymphatic capillaries.
In simple words: Lymph is clear fluid that comes from between our cells. It goes back into the blood system and helps our body fight sickness.

🎯 Exam Tip: Distinguish lymph from blood plasma; lymph is derived from tissue fluid and lacks red blood cells.

Question 23. What is the name of upper chambers of heart?
Answer: The upper chambers of the heart are called atria (singular: atrium) or auricles. There are two atria: the right atrium and the left atrium. These chambers receive blood from the body and lungs before pumping it to the lower chambers (ventricles). They act as collecting chambers for blood.
In simple words: The top parts of the heart are called atria. They take in blood before it goes to the bottom parts.

🎯 Exam Tip: Clearly state both terms "atria" and "auricles" and their function in receiving blood.

Question 24. What is the name of lower chambers of hearth?
Answer: The lower chambers of the heart are called ventricles. There are two ventricles: the right ventricle and the left ventricle. These powerful chambers pump blood out of the heart, the right ventricle to the lungs and the left ventricle to the rest of the body. They are the main pumping chambers.
In simple words: The bottom parts of the heart are called ventricles. They pump blood out to the lungs and the body.

🎯 Exam Tip: Emphasize the pumping action of the ventricles and their destinations (lungs vs. body).

Question 27. What is an artery?
Answer: An artery is a blood vessel that carries blood away from the heart to other organs and tissues in the body. Most arteries carry oxygenated blood, which is rich in oxygen. These vessels have thick, muscular walls to withstand the high pressure of blood pumped by the heart. They ensure all body parts get fresh oxygen.
In simple words: Arteries are tubes that take blood away from the heart. Most of them carry blood full of oxygen to our body parts.

🎯 Exam Tip: Define arteries by the direction of blood flow (away from heart) and typically their oxygen content.

Question 28. What is a vein?
Answer: A vein is a blood vessel that carries blood back towards the heart from various organs and tissues. Most veins carry deoxygenated blood, which is low in oxygen and rich in carbon dioxide. Veins have thinner walls and contain valves to prevent the backflow of blood, as the blood pressure is lower. They bring "used" blood back to the heart to be sent to the lungs.
In simple words: Veins are tubes that bring blood back to the heart. Most carry blood that has less oxygen.

🎯 Exam Tip: Contrast veins with arteries, focusing on the direction of blood flow (towards heart), oxygen content, and presence of valves.

Question 29. What is excretion?
Answer: Excretion is the process by which living organisms remove metabolic waste products and excess substances from their body. These waste products, if not removed, can be harmful or even toxic. The kidneys, lungs, and skin are major organs involved in excretion. This process helps maintain a healthy balance inside the body.
In simple words: Excretion is how our body gets rid of waste products. It's like taking out the trash from our cells.

🎯 Exam Tip: Define excretion clearly and mention some key excretory organs to show understanding.

Question 30. Give two examples of ammonotelic animals.
Answer: Two examples of ammonotelic animals are fish and frogs. Ammonotelic animals excrete ammonia as their primary nitrogenous waste product. Ammonia is very toxic and requires a lot of water for its excretion, which is why these animals usually live in aquatic environments. Their watery homes help them safely dispose of ammonia.
In simple words: Fish and frogs are ammonotelic animals. They get rid of waste as ammonia, which needs a lot of water to go away safely.

🎯 Exam Tip: When listing examples, briefly state the characteristic that makes them fit the category (e.g., excreting ammonia).

Question 31. Give two examples of uricotelic animals.
Answer: Two examples of uricotelic animals are birds and lizards. Uricotelic animals excrete uric acid as their main nitrogenous waste. Uric acid is less toxic than ammonia and can be excreted with very little water, which is an important adaptation for animals living in dry environments or those that need to conserve water. This helps them stay hydrated.
In simple words: Birds and lizards are uricotelic animals. They get rid of waste as uric acid, which helps them save water.

🎯 Exam Tip: Connect the type of excretory product (uric acid) with the animal's habitat or need for water conservation.

Question 32. Which is the functional unit of kidney?
Answer: The functional unit of the kidney is the nephron. Each kidney contains millions of nephrons, which are responsible for filtering blood, reabsorbing useful substances, and forming urine. The nephron is like a tiny filter that cleans the blood and makes urine. Understanding its structure helps explain how kidneys work.
In simple words: The nephron is the tiny working part of the kidney. It cleans the blood and makes urine.

🎯 Exam Tip: State the term clearly and briefly explain its primary function (filtering blood, forming urine).

Question 34. What are secondary sexual characters?
Answer: Secondary sexual characters are physical features that appear during puberty and help distinguish males from females, but are not directly involved in reproduction. Examples include facial hair and a deeper voice in males, and breast development and wider hips in females. These characteristics are influenced by sex hormones and signal sexual maturity. They help identify an individual's sex at a glance.
In simple words: These are body changes during teenage years that show if someone is male or female, like a deeper voice or growing breasts. They are not directly for making babies.

🎯 Exam Tip: Define secondary sexual characters and provide clear examples for both males and females.

Question 35. Which is the primary reproductive organ in males?
Answer: The primary reproductive organ in males is the testis (plural: testes). The testes are responsible for producing sperm, which are male gametes, and male sex hormones, primarily testosterone. These are essential for both reproduction and the development of male characteristics. They are crucial for male fertility.
In simple words: The testis is the main male reproductive organ. It makes sperm and male hormones.

🎯 Exam Tip: Specify both functions of the testis: sperm production and hormone secretion.

Question 36. Which is the primary reproductive organ in females?
Answer: The primary reproductive organ in females is the ovary (plural: ovaries). The ovaries produce eggs, which are female gametes, and female sex hormones, such as estrogen and progesterone. These hormones are important for the reproductive cycle and the development of female characteristics. They also prepare the body for pregnancy.
In simple words: The ovary is the main female reproductive organ. It makes eggs and female hormones.

🎯 Exam Tip: Similar to males, remember both functions of the ovary: egg production and hormone secretion.

Question 37. What is gametogenesis?
Answer: Gametogenesis is the biological process by which diploid or haploid precursor cells undergo cell division and differentiation to form mature haploid gametes. In simple terms, it is the formation of male gametes (sperm) and female gametes (eggs). This process ensures that organisms can reproduce sexually. It is a key part of sexual reproduction.
In simple words: Gametogenesis is the process where male and female sex cells (sperm and eggs) are made. It is how new life can begin.

🎯 Exam Tip: Clearly state that gametogenesis refers to the formation of both male and female gametes.

Question 38. What is fertilization?
Answer: Fertilization is the process where a male gamete (sperm) fuses with a female gamete (egg) to form a zygote. This fusion typically occurs in the fallopian tube in humans and marks the beginning of embryonic development. It combines genetic material from both parents, creating a new unique individual. This is a crucial step in sexual reproduction.
In simple words: Fertilization is when a sperm joins with an egg. This creates a new cell that can grow into a baby.

🎯 Exam Tip: Focus on the fusion of male and female gametes and the formation of a zygote in your definition.

Question 39. What is zygote?
Answer: The zygote is the single cell formed as the end product of fertilization. It contains all the genetic information from both parents and is the very first stage of development for a new organism. This cell will then divide repeatedly to form an embryo. It marks the start of a new life.
In simple words: A zygote is the first cell created when a sperm and egg join. It has all the instructions to grow a new living being.

🎯 Exam Tip: Define zygote as the product of fertilization and the initial single-celled stage of development.

Question 42. What is autonomous nervous system?
Answer: The autonomous nervous system (ANS) is the part of the nervous system that controls involuntary actions in the body. These are actions that happen automatically without us having to think about them, such as heart rate, digestion, breathing, and blood pressure. It helps keep our body's internal environment stable. This system works behind the scenes to keep us alive.
In simple words: The autonomous nervous system controls things our body does by itself, like our heartbeat and digestion, without us even thinking about it.

🎯 Exam Tip: Emphasize "involuntary actions" and provide common examples like heart rate and digestion.

Question 43. What is axon?
Answer: An axon is a long, tail-like structure that extends from the cell body of a neuron. Its primary function is to transmit electrical signals, called nerve impulses or action potentials, away from the neuron's cell body to other neurons, muscles, or glands. Axons can be very long, allowing rapid communication over distances. They are essential for nerve communication.
In simple words: An axon is the long part of a nerve cell. It sends messages from one nerve cell to another, or to muscles.

🎯 Exam Tip: Define axon as the output part of a neuron that carries signals away from the cell body.

Question 44. What are the main parts of hind brain?
Answer: The main parts of the hindbrain are the cerebellum, the pons, and the medulla oblongata. These structures are located at the back of the brain, connecting it to the spinal cord. They are responsible for vital functions such as balance, coordination, breathing, and heart rate. The hindbrain is essential for our basic survival.
In simple words: The hindbrain has three main parts: the cerebellum, pons, and medulla. They help with balance, breathing, and keeping our heart beating.

🎯 Exam Tip: List all three main parts of the hindbrain and briefly mention their collective role in basic life functions.

Question 45. What is neuron?
Answer: A neuron, also known as a nerve cell, is the functional unit of the nervous system. It is a specialized, unicellular structure that transmits electrical and chemical signals throughout the body. Neurons are responsible for processing and transmitting information, enabling communication between different parts of the body. They are the building blocks of our brain and nerves.
In simple words: A neuron is a nerve cell, the basic unit of our nervous system. It sends messages around the body to help us think and move.

🎯 Exam Tip: Define a neuron as the functional unit of the nervous system and highlight its role in transmitting signals.

Question 46. What is an endocrine gland?
Answer: An endocrine gland is a ductless gland that secretes hormones directly into the bloodstream. Unlike exocrine glands, which release their products through ducts, endocrine glands distribute hormones throughout the body to regulate various physiological processes. Examples include the thyroid and pituitary glands. These hormones act as messengers, controlling many body functions.
In simple words: An endocrine gland is a gland without a tube that puts hormones straight into the blood. These hormones act like messengers for the body.

🎯 Exam Tip: The key characteristic of endocrine glands is "ductless" and "secreting hormones directly into the bloodstream."

Question 47. Growth hormone is secreted by which gland?
Answer: Growth hormone is secreted by the pituitary gland. The pituitary gland, often called the "master gland," is located at the base of the brain. It controls growth, metabolism, and many other endocrine functions by secreting various hormones, including growth hormone. This hormone helps children grow taller and helps maintain body tissues in adults.
In simple words: The pituitary gland makes growth hormone. This hormone helps us grow and affects many other body functions.

🎯 Exam Tip: Identify the pituitary gland as the source and briefly mention its common name ("master gland") or key functions.

Question 1. What is digestion? What is the need for digestion?
Answer: Digestion is the process of converting complex nutrients into simple, soluble, and absorbable substances. Food components are often complex molecules that the body cannot directly use. They need to be broken down into simpler forms so they can be absorbed into the bloodstream and used by cells for energy, growth, and repair. Without digestion, our bodies would not be able to get the nutrients they need from food.
In simple words: Digestion is breaking down big food parts into small ones. We need it so our body can take in nutrients and use them for energy and growth.

🎯 Exam Tip: Clearly define digestion and then explain the "why" by mentioning absorption and utilization of nutrients by the body.

Question 2. What are the main parts of alimentary canal?
Answer: The main parts of the alimentary canal are the mouth, pharynx, oesophagus, stomach, small intestine, large intestine, and rectum. This long tube-like structure, also known as the digestive tract, is where food passes through and gets processed. Each part has a specific role in breaking down food and absorbing nutrients. It starts at the mouth and ends at the anus.
In simple words: The main parts of the food tube are the mouth, throat, food pipe, stomach, small and large intestines, and rectum. Food travels through all these parts.

🎯 Exam Tip: List the parts in sequence, as this helps demonstrate a systematic understanding of the digestive pathway.

Question 3. Name different types of salivary gland.
Answer: There are three main types of salivary glands that produce saliva in the mouth. These are the parotid gland, submandibular gland, and sublingual gland. Saliva helps in moistening food, starting carbohydrate digestion, and keeping the mouth clean. Each gland releases saliva into the mouth through small ducts.
In simple words: The three types of salivary glands are parotid, submandibular, and sublingual. They make spit to help with digestion.

🎯 Exam Tip: Remember the names of all three major salivary glands for a complete answer.

Question 5. Briefly explain the main parts of small intestine.
Answer: The small intestine is divided into three main parts: the duodenum, the jejunum, and the ileum.

• Duodenum: This is the first and shortest part, located just after the stomach. Most of the digestive juices from the pancreas and liver enter here, and a lot of food digestion happens.
• Jejunum: This is the middle part of the small intestine. The primary role of the jejunum is the absorption of most digested food. Special cells called enterocytes help in this process.
• Ileum: This is the last and longest part of the small intestine, connecting to the large intestine. The ileum absorbs any remaining nutrients, such as vitamin B12 and bile salts, that were not absorbed earlier.

Each part is specialized for efficient digestion and absorption of nutrients.
In simple words: The small intestine has three parts: duodenum, jejunum, and ileum. The duodenum helps digest food, the jejunum absorbs most food, and the ileum absorbs the last bits of nutrients.

🎯 Exam Tip: Name all three parts and briefly describe the primary function of each for a comprehensive answer.

Question 6. Briefly explain the main parts in which colon of large intestine can be divided.
Answer: The colon, which is a major part of the large intestine, can be divided into four main sections:

• Ascending Colon: This part goes upwards from the cecum, located near the appendix. It is about 15 cm long.
• Transverse Colon: This section runs horizontally across the upper abdomen. It is the longest part of the colon, about 50 cm long.
• Descending Colon: This part extends downwards on the left side of the abdomen. It is approximately 25 cm long.
• Sigmoid Colon: This is the S-shaped final section of the colon that connects to the rectum. It is about 40 cm long.

These parts work together to absorb water and electrolytes, and to form and store feces before elimination.
In simple words: The colon has four parts: ascending (goes up), transverse (goes across), descending (goes down), and sigmoid (S-shaped). They all help remove water and store waste.

🎯 Exam Tip: When describing parts of the colon, mentioning their relative position or direction (e.g., "ascending upwards") helps clarify the explanation.

Question 8. Explain the digestion of food in mouth.
Answer: Digestion in the mouth begins with mastication, which is the physical process of chewing food into smaller pieces. This physical breakdown helps mix food with saliva. Saliva contains mucus, which lubricates the food, and an enzyme called salivary amylase (or ptyalin), which starts the chemical digestion of starch. About 30% of the starch in food is converted into maltose in the buccal cavity. The smaller food particles and enzyme action make it easier for the food to travel down the oesophagus. This initial breakdown is vital for later stages of digestion.
In simple words: In the mouth, we chew food into small bits. Saliva mixes with it, making it wet and starting to break down starches with a special helper called amylase.

🎯 Exam Tip: Mention both mechanical (mastication) and chemical (salivary amylase) digestion occurring in the mouth.

Question 9. Explain the digestion of food in stomach.
Answer: The stomach plays a crucial role in food digestion. It secretes three main digestive juices: mucus, proenzyme pepsinogen, and hydrochloric acid. Mucus protects the stomach lining, while hydrochloric acid, secreted by oxyntic cells, kills any germs in food and makes the stomach acidic. This acidic environment is essential for the activation of pepsinogen into pepsin, which then begins to digest proteins into smaller peptides. In small children, rennin is also secreted to help digest milk proteins. The stomach muscles also churn the food, mixing it thoroughly with these digestive juices. This turns the food into a thick liquid called chyme.
In simple words: In the stomach, acid kills germs and a special enzyme starts breaking down proteins. Mucus protects the stomach walls. Food is also churned here.

🎯 Exam Tip: Discuss the roles of hydrochloric acid, pepsin, and mucus, and briefly mention the mechanical churning action of the stomach.

Question 10. Write a short note on exchange of gases in lungs.
Answer: The exchange of gases, oxygen and carbon dioxide, primarily occurs in the alveoli of the lungs. Alveoli are tiny air sacs surrounded by a network of capillaries. Oxygen from the inhaled air in the alveoli moves across the thin alveolar and capillary walls into the blood, where it binds to haemoglobin. At the same time, carbon dioxide, a waste product from the body's cells, moves from the blood in the capillaries into the alveoli to be exhaled. This movement is driven by differences in pressure (partial pressures) of these gases. This constant exchange ensures fresh oxygen is delivered and waste carbon dioxide is removed.
In simple words: In our lungs, tiny air sacs called alveoli swap gases. Oxygen goes from the air into the blood, and waste carbon dioxide goes from the blood into the air to be breathed out.

🎯 Exam Tip: Highlight the alveoli as the primary site of gas exchange and mention that the process is driven by pressure differences.

Question 11. Write a short note on RBCs.
Answer: Red Blood Cells (RBCs), also known as erythrocytes, make up about 99% of all blood cells. They contain a protein called haemoglobin, which gives them their characteristic red color and is responsible for transporting oxygen from the lungs to the body's tissues. RBCs are unique because they lack a nucleus, which allows them to carry more haemoglobin. They have a lifespan of approximately 120 days. These cells are vital for ensuring every part of the body gets enough oxygen.
In simple words: Red blood cells are the most common blood cells. They have a red protein called haemoglobin that carries oxygen around our body. They live for about 120 days.

🎯 Exam Tip: Include key facts about RBCs: abundance, haemoglobin content, oxygen transport, lack of nucleus, and lifespan.

Question 12. What do you understand by types of blood?
Answer: Blood types are classifications of blood based on the presence or absence of specific antigens (A and B) on the surface of red blood cells. The ABO blood group system defines four main types: A, B, AB, and O.

• Blood group A: Has A antigens on red blood cells.
• Blood group B: Has B antigens on red blood cells.
• Blood group AB: Has both A and B antigens on red blood cells.
• Blood group O: Has neither A nor B antigens on red blood cells.

These classifications are crucial for safe blood transfusions, as giving the wrong blood type can cause a severe immune reaction. Another important blood type is Rh positive or negative.
In simple words: Blood types are ways to group blood based on special markers called antigens on red blood cells. The main types are A, B, AB, and O, which are important for safe blood transfusions.

🎯 Exam Tip: Explain that blood types are based on antigens and list the four main ABO types with their corresponding antigens.

Question 14. What is excretion? What is the need for excretion?
Answer: Excretion is the biological process of removing metabolic waste products and excess substances from the body. During various metabolic processes, cells produce waste materials like urea, carbon dioxide, and excess salts. If these waste products are not removed, they can accumulate and become toxic, harming the body's tissues and organs. Therefore, excretion is essential to maintain internal balance (homeostasis) and ensure the body functions correctly. This constant cleaning helps keep us healthy.
In simple words: Excretion is when our body gets rid of waste. We need to excrete waste because if it stays inside, it can become harmful and make us sick.

🎯 Exam Tip: Define excretion and clearly state that its necessity stems from preventing the accumulation of harmful metabolic wastes.

Question 15. Explain the structure of a nephron.
Answer: A nephron is the microscopic functional unit of the kidney responsible for filtering blood and forming urine. It consists of two main parts: a filtering unit called the renal corpuscle and a long, convoluted renal tubule.

• Renal Corpuscle: This includes the glomerulus, a tuft of tiny blood capillaries, encased within a cup-shaped structure called Bowman's capsule. Blood enters the glomerulus through the renal artery, where it is filtered under pressure.
• Renal Tubule: This long, twisted tube extends from Bowman's capsule. It reabsorbs useful substances like water, glucose, and amino acids back into the blood while secreting waste products into the forming urine. The tubule consists of several segments, including the proximal convoluted tubule, loop of Henle, and distal convoluted tubule, before finally draining into a collecting duct.

This intricate structure allows for precise control over blood composition and waste removal.
In simple words: A nephron is the tiny part of the kidney that cleans blood. It has a filter (glomerulus in Bowman's capsule) and a long tube. The filter takes out waste, and the tube puts good things back into the blood while making urine.

🎯 Exam Tip: Break down the nephron into its main components (renal corpuscle, renal tubule) and explain the basic function of each part for clarity.

Question 16. What are the changes which take place in adolescent boys?
Answer: During adolescence, boys undergo several physical changes due to hormonal shifts, mainly testosterone. These secondary sexual characteristics include:

• Broadening of Shoulders: The skeletal structure changes, leading to wider shoulders and a generally more muscular build.
• Development of Muscles: Muscle mass increases significantly, contributing to greater strength and a more mature physique.

Other changes include the growth of facial and body hair, deepening of the voice, and an increase in height. These changes are natural and signify the transition to adulthood.
In simple words: During teenage years, boys' bodies change. Their shoulders get wider, and their muscles grow bigger.

🎯 Exam Tip: When listing changes, use clear, concise points and ensure they are specific to adolescent boys.

Question 17. Make a well labeled diagram of male reproductive system,
Answer: (A diagram of the male reproductive system, showing parts like the bladder, seminal vesicle, vas deferens, prostate gland, penis, urethra, epididymis, and testicle, would be placed here). This diagram helps visualize the intricate arrangement of organs responsible for reproduction and urinary function in males. It illustrates how these structures are connected.
In simple words: A picture showing the parts of the male reproductive system, like the testes, tubes, and glands.

🎯 Exam Tip: Practice drawing and labeling all key components of the male reproductive system, paying attention to accuracy and clarity.

Question 18. Make a well labeled diagram of female reproductive system.
Answer: (A diagram of the female reproductive system, showing parts like the fundus, egg, fallopian tube, uterine cavity, endometrium, ovary, uterus, myometrium, cervix, and vagina, would be placed here). This diagram illustrates the complex organs involved in egg production, fertilization, and supporting a pregnancy. It helps understand the pathway of an egg and where a baby grows.
In simple words: A picture showing the parts of the female reproductive system, like the ovaries, uterus, and fallopian tubes.

🎯 Exam Tip: Ensure all important parts like the ovaries, fallopian tubes, uterus, and vagina are correctly drawn and labeled in the diagram.

Question 19. Write a short note on cleavage and implantation.
Answer:

• Cleavage: After fertilization, the zygote undergoes rapid mitotic cell divisions without significant growth. This process is called cleavage, and it results in a multicellular structure known as a blastula. Each division creates more cells, but the overall size of the embryo doesn't change much.
• Implantation: Following cleavage, the blastula develops into a blastocyst. Implantation is the process where this blastocyst attaches and embeds itself into the endometrium (the inner lining) of the uterus. This usually happens about 6-12 days after fertilization, allowing the embryo to receive nutrients and continue developing. Successful implantation is crucial for a pregnancy to continue.

These early stages are fundamental for the formation of a new individual.
In simple words: Cleavage is when the first cell (zygote) divides many times to make more cells, forming a ball called a blastula. Implantation is when this cell ball attaches to the wall of the uterus to start a pregnancy.

🎯 Exam Tip: Differentiate clearly between cleavage (cell division without growth) and implantation (attachment to uterine wall), mentioning the resulting structures for each.

Question 21. Write a short note on thyroxin.
Answer: Thyroxin is a crucial hormone produced by the thyroid gland, located in the neck. Iodine is an essential component of this hormone. Thyroxin plays many vital roles, including controlling the body's metabolism of carbohydrates, proteins, and fats, meaning how the body uses energy. It also helps in the production of red blood cells. A deficiency of iodine can lead to reduced thyroxin production, causing a disease called goiter, where the thyroid gland enlarges. This hormone is like the body's main regulator for energy use.
In simple words: Thyroxin is a hormone made by the thyroid gland. It uses iodine and controls how our body uses food for energy. Not enough iodine can cause problems like goiter.

🎯 Exam Tip: Mention the gland producing thyroxin, the importance of iodine, and its primary role in regulating metabolism.

Question 1. Describe the structure and functioning of nephrons.
Answer: The nephron is the fundamental structural and functional unit of the kidney, responsible for filtering blood and producing urine. Each kidney contains millions of nephrons.
(A diagram showing the structure of a nephron with parts like Bowman's capsule, glomerulus, renal artery, and collecting duct would be placed here).
Its structure includes:

1. Renal Corpuscle: This part consists of the glomerulus, a network of tiny blood capillaries, enclosed within a cup-shaped structure called Bowman's capsule. Filtration of blood begins here.
2. Renal Tubule: A long, convoluted tube extending from Bowman's capsule, divided into the proximal convoluted tubule (PCT), loop of Henle, and distal convoluted tubule (DCT), which then connects to a collecting duct.

The functioning of nephrons involves three main steps:

1. Filtration: Blood enters the glomerulus under high pressure. Water, salts, glucose, amino acids, and urea are filtered out of the blood into Bowman's capsule, forming a fluid called glomerular filtrate. Larger substances like proteins and blood cells do not pass through.
2. Reabsorption: As the filtrate passes through the renal tubule, essential substances like most of the water, all glucose, and amino acids are reabsorbed back into the bloodstream by surrounding capillaries. This ensures the body retains important nutrients and water.
3. Secretion: Some waste products and excess ions that were not filtered initially are actively secreted from the blood into the renal tubule. This fine-tunes the composition of urine.

Finally, the modified filtrate, now called urine, collects in the collecting ducts and flows out of the kidney. The nephron's intricate design allows for efficient blood purification and maintains the body's fluid and electrolyte balance.
In simple words: A nephron is the tiny part of the kidney that cleans our blood. It filters blood in Bowman's capsule, takes back good things in a tube, and then secretes waste to make urine. This keeps our body healthy by removing bad stuff.

🎯 Exam Tip: Clearly label the parts of the nephron in your diagram and explain the three steps of urine formation (filtration, reabsorption, secretion) in order.

Question 2. Describe the digestive system.
Answer: The human digestive system is a complex network of organs that works together to break down food, absorb nutrients, and eliminate waste. It consists of the alimentary canal (a long tube through which food passes) and several accessory digestive glands.
The main parts of the digestive system are as follows:

1. Mouth (Buccal Cavity): Digestion begins here. Food is chewed (mastication) and mixed with saliva, which contains enzymes to start breaking down carbohydrates.
2. Pharynx: A muscular tube behind the mouth that serves as a passageway for both food and air. It ensures food moves towards the oesophagus.
3. Oesophagus (Food Pipe): A tube that carries food from the pharynx to the stomach through wave-like muscle contractions called peristalsis.
4. Stomach: A J-shaped muscular organ that churns food and mixes it with gastric juices (hydrochloric acid and pepsin) to break down proteins and kill germs.
5. Small Intestine: A long, coiled tube where most chemical digestion and nutrient absorption occur. It has three parts: the duodenum, jejunum, and ileum. It receives digestive enzymes from the pancreas and bile from the liver.
6. Large Intestine: Absorbs water and electrolytes from undigested food, forming feces. It has parts like the cecum, colon, and rectum.
7. Rectum: Stores feces before elimination.
8. Anus: The opening through which feces are expelled from the body.

Accessory glands like the salivary glands, liver, and pancreas produce enzymes and bile that aid in digestion, making this system a powerful nutrient extractor for the body.
In simple words: The digestive system is a long pathway that starts at our mouth and ends at the anus. It breaks down food into small parts to give us energy and nutrients. It includes the mouth, food pipe, stomach, and intestines, along with glands like the liver and pancreas.

🎯 Exam Tip: List the organs of the alimentary canal in order and briefly state the main function of each part to show a complete understanding.

Question 3. Explain breathing mechanism.
Answer: The breathing mechanism involves two main processes: inhalation (breathing in) and exhalation (breathing out).

• Inhalation: This is an active process. The diaphragm, a large muscle at the base of the chest, contracts and flattens. At the same time, the intercostal muscles between the ribs contract, pulling the rib cage upwards and outwards. These actions increase the volume of the thoracic cavity (chest cavity). As the volume increases, the pressure inside the lungs decreases, becoming lower than the atmospheric pressure outside. This pressure difference causes air to rush into the lungs through the nasal passages (or mouth) and trachea, filling the alveoli.
• Exhalation: This is usually a passive process at rest. The diaphragm relaxes and moves upwards, becoming dome-shaped. The intercostal muscles also relax, causing the rib cage to move downwards and inwards. These actions decrease the volume of the thoracic cavity. As the volume decreases, the pressure inside the lungs increases, becoming higher than the atmospheric pressure. This forces the air out of the lungs. During forced exhalation (like during exercise), additional muscles actively help push air out.

Both processes are controlled by the respiratory center in the brain, ensuring a continuous supply of oxygen and removal of carbon dioxide. This constant movement of air is essential for life.
In simple words: Breathing in happens when a muscle called the diaphragm moves down and our ribs go up, making more space for air in our chest. This pulls air into our lungs. Breathing out happens when the diaphragm goes up and ribs go down, making less space, which pushes air out.

🎯 Exam Tip: Describe both inhalation and exhalation, focusing on the role of the diaphragm and intercostal muscles, and how pressure changes drive air movement.

Question 4. Differentiate between arteries and veins.
Answer:

This distinction in structure and function allows each type of vessel to perform its specific role efficiently in the circulatory system. Their differences ensure blood flows in the right direction and pressure.
In simple words: Arteries are thick tubes that carry blood away from the heart, mostly with oxygen, and have no valves. Veins are thinner tubes that carry blood back to the heart, mostly without oxygen, and have valves to stop blood from flowing backward.

🎯 Exam Tip: Focus on the five key differences: wall thickness, location, direction of blood flow, oxygen content (with exceptions), and presence of valves.

Question 5. (a) Name all the digestive enzymes 1 complex carbohydrates into glucose present in our digestive system. and fats into fatty acid and glycerol. (b) Explain the process of digestion of carbohydrates fats and proteins. (c) Why do people complain of acidity problems on consuming too much of fats and proteins?
Answer:
(a) The digestive enzymes present in our system are: Salivary amylase, pepsin, trypsin, lipase, pancreatic amylase.
(b) Digestion of carbohydrates, fats, and proteins:

• Carbohydrates: Digestion starts in the mouth with salivary amylase breaking down complex starch into simpler sugars. This process continues in the small intestine with pancreatic amylase, further breaking down carbohydrates into glucose for absorption.
• Proteins: Digestion begins in the stomach with pepsin, which breaks proteins into smaller peptides. In the small intestine, trypsin and chymotrypsin (from the pancreas) continue this process, eventually breaking them down into amino acids, which are then absorbed.
• Fats: Digestion primarily occurs in the small intestine. Bile, produced by the liver, emulsifies fats (breaks them into tiny droplets). Then, lipase (from the pancreas) breaks these emulsified fats into fatty acids and glycerol, which can be absorbed.

This coordinated action ensures complete breakdown of food for nutrient absorption.
In simple words: Enzymes like amylase break down carbs, pepsin and trypsin break down proteins, and lipase breaks down fats. This happens from the mouth to the small intestine, turning big food parts into tiny ones our body can use.

🎯 Exam Tip: When explaining digestion, specify where each type of food (carbohydrates, proteins, fats) begins to be digested and the main enzymes involved at each stage.

Question 6. (a) Draw a labelled sectional (RBSESolutions.com) view of human heart. (b) State the functions of the following components of transport system: (i) Blood (ii) Lymph
Answer:
(a) Diagram of human heart.

(b) (i) Functions of Blood:
1. It helps to keep the body temperature steady.
2. It moves important things like food, water, and amino acids around the body.
3. It protects the body from illness by fighting off germs.
4. Blood helps stop bleeding by forming clots if there is an injury.
5. It carries oxygen to give the body energy. The blood is vital for life, delivering nutrients and removing waste products efficiently.
In simple words: Blood keeps our body warm, carries food and water, fights germs, helps stop bleeding, and carries oxygen for energy.

🎯 Exam Tip: When drawing diagrams, ensure all key parts are correctly labelled and clearly visible to score full marks.

Question 8. What are the different parts of the brain? Give (RBSESolutions.com) functions of each part.
Answer: The brain has three main parts: the forebrain, the midbrain, and the hindbrain.
**Forebrain:**
1. The forebrain includes the cerebrum and the olfactory lobes.
2. The cerebrum is the biggest part of the brain and has two halves called cerebral hemispheres. It has areas that receive information from our sense organs and areas that send signals to our muscles.
3. Specific areas in the cerebr handle different tasks, like hearing, smelling, and seeing.
**Midbrain:**
This is a very small part of the brain, located between the forebrain and hindbrain. The midbrain has four lobes called corpora quadrigemina. The top two lobes help with vision, while the bottom two help with hearing.
**Hindbrain:**
1. The cerebellum helps with body movement, balance, and posture. It ensures our movements are smooth and coordinated.
2. The pons controls our breathing.
3. The medulla is in charge of automatic body actions like salivation, vomiting, sneezing, and coughing.
In simple words: The brain has three parts: forebrain (for thinking, senses), midbrain (for vision, hearing), and hindbrain (for balance, breathing, and body actions). Each part does important jobs to keep us functioning.

🎯 Exam Tip: Remember to list both the main parts of the brain and a specific function for each to provide a complete answer.

Question 9. Name the secretions of the following glands and give (RBSESolutions.com) their function: pituitary, testis and ovary.
Answer:
* **Pituitary gland:** It produces growth hormone, which manages how the body grows and develops. Too much of this hormone causes gigantism, and too little causes dwarfism.
* **Testis:** It secretes testosterone. This hormone controls the male reproductive organs and also causes male secondary sexual characteristics to develop, like a deeper voice or more body hair.
* **Ovary:** It secretes estrogen. This hormone controls the female reproductive organs and helps develop female secondary sexual characteristics. These hormones are crucial for puberty and reproduction.
In simple words: The pituitary gland makes growth hormone. The testis makes testosterone for male traits. The ovary makes estrogen for female traits.

🎯 Exam Tip: When listing glands and their secretions, always mention the key hormone and its primary function clearly.

Question 10. Differentiate between
(a) Spinal nerve and cranial nerve
(b) Dendrite and axon
(c) Central nervous system and peripheral nervous system
Answer:
(a)

(b)

(c)

In simple words: Spinal nerves come from the spinal cord for head/neck actions, while cranial nerves come from the brain for body parts below the neck. Dendrites receive signals, axons send them. The central nervous system is the brain and spinal cord, controlling everything; the peripheral nervous system is all the other nerves, just carrying signals.

🎯 Exam Tip: For differentiation questions, always use a table format and ensure you provide clear, contrasting points for each pair.