Maharashtra Board Class 5 EVS Part 1 Chapter 21 Busy at Work Our Internal Organs Solutions

5th Standard EVS 1 Lesson Number 21 Question Answer Busy At Work – Our Internal Organs Maharashtra Board

Std 5 EVS 1 Chapter 21 Question Answer

Question 1. A person has fainted and a crowd of people has surrounded him.
Answer: When a person faints and a crowd gathers, the first step is to ask the crowd to move back to allow fresh air to reach the person. The fainted person should be laid down on their back with their legs slightly elevated to improve blood flow to the brain. Loosen any tight clothing around their neck or chest. If the person does not regain consciousness quickly, medical assistance should be called immediately.
In simple words: If someone faints and a crowd gathers, clear the crowd for fresh air, lay the person down with raised legs, and call for medical help if they don't wake up soon.

🎯 Exam Tip: For scenario-based questions, always provide practical, immediate actions, prioritize safety, and remember to include seeking professional help if the situation doesn't improve.

Use Your Brain Power!

Question (a) Why do we sometimes choke suddenly while eating?
Answer: The food that we chew in the mouth enters the oesophagus after swallowing. The upper ends of both the oesophagus and the windpipe open in the throat next to each other. When we swallow the food in a hurry while eating, sometimes the food suddenly enters the windpipe causing us to suddenly choke. This reflex action helps prevent food from entering the lungs.
In simple words: We choke when food accidentally goes into our windpipe instead of our food pipe, usually when we eat too fast.

🎯 Exam Tip: When explaining bodily functions, use clear, sequential steps to describe the process and its cause.

Question (b) How is the air that we inhale purified in our body?
Answer: The inner lining of the respiratory tract secretes a sticky substance called mucus. It also has hair-like structures called cilia. The air that we inhale is purified with the help of this mucus and cilia. The cilia filter the dust, smoke, micro-organisms etc. and these substances get entangled in the sticky mucus and stick to the inner lining of the nose. Sometimes the cilia push out these substances towards the nostrils which is then blown out by sneezing. Thus this is how air that we inhale is purified, ensuring cleaner air reaches our lungs.
In simple words: Our nose has sticky mucus and tiny hairs (cilia) that trap dust and germs from the air we breathe, cleaning it before it goes to our lungs.

🎯 Exam Tip: Remember to mention both mucus and cilia when describing air purification in the respiratory system, as both play crucial roles.

Fill In The Blanks.

Question (a) ................................... gas is continuously transported to all parts of the body.
(a) Oxygen
(b) Carbon dioxide
(c) Nitrogen
Answer: (a) Oxygen
In simple words: Oxygen is the gas our body constantly moves around to keep all its parts working.

🎯 Exam Tip: For fill-in-the-blanks, always read the sentence carefully and choose the option that makes the most biological sense in context.

Question (b) The stomach is like a ...................................
(a) ball
(b) skin

🎯 Exam Tip: When answering questions about body parts, consider their function and physical characteristics to determine the best comparison.

Match The Columns

Question 1. Match the columns:

🎯 Exam Tip: When matching columns, draw lines or write the correct pair next to each item. Double-check each match to ensure accuracy, especially for organs with multiple functions.

Answer The Following Questions

Question (a) Name the systems that carry out the different functions of the body.
Answer: The systems that carry out the different functions of the body are Digestive system, which processes food and absorbs nutrients.
In simple words: Different body systems like the digestive system work together to perform various tasks.

🎯 Exam Tip: When asked to name systems, list as many relevant ones as you can recall, such as the digestive, respiratory, circulatory, and nervous systems, along with a brief mention of their primary role.

Question (b) Describe how the exchange of oxygen and carbon dioxide gases takes place in the lungs.
Answer: The air that we inhale contains oxygen. This outside air reaches the lungs with the help of the respiratory organs like nose, trachea and diaphragm. When the outside air reaches the alveoli present in the lungs it passes into the thin blood vessels around the alveoli. With the blood, it flows to the various parts of the body. At the same time the carbon dioxide that is brought by the blood from all parts of the body leave the blood and enters the alveoli. When we exhale this carbon dioxide is given out. In this way the exchange of oxygen and carbon dioxide gases takes place in the lungs. This continuous process is vital for maintaining life.
In simple words: Oxygen from the air goes into tiny sacs in the lungs (alveoli) and then into the blood. Carbon dioxide from the blood moves into the alveoli to be breathed out. This constant swap keeps our body supplied with oxygen.

🎯 Exam Tip: When describing physiological processes, use clear, sequential steps and mention the key organs involved, such as alveoli and blood vessels for gas exchange.

Question (c) Why do we call saliva, a digestive juice?
Answer: The digestive juice are the juices secreted by the glands present outside the digestive system and they help in digesting the food. When food is taken in the mouth, saliva is secreted by the glands called salivary glands into the mouth. The saliva then mixes with the food that is chewed and it converts the food into soft moist ball called bolus which is easy to swallow. The saliva also digests the starch present in the food. Since saliva helps in digestion of food it, is called a digestive juice. This initial breakdown of food is crucial for the entire digestive process.
In simple words: Saliva is called a digestive juice because it's made by glands and helps break down food, especially starches, right in your mouth, making it easier to swallow and digest.

🎯 Exam Tip: To explain why saliva is a digestive juice, highlight its origin from salivary glands and its role in both mechanical (forming bolus) and chemical (starch digestion) breakdown of food.

Question 6. Choose the appropriate word from the brackets:
Answer: [Content for this question is missing from the source document.]
In simple words: This question requires selecting the correct word from a given set of options to complete a sentence or phrase.

🎯 Exam Tip: For fill-in-the-blanks questions, always read the sentence carefully and consider the context to choose the most suitable word that fits grammatically and semantically.

Question (a) Respiration takes place because of its up and down movement.
Answer: diaphragm. The diaphragm's rhythmic movement is crucial for the mechanics of breathing.
In simple words: Breathing happens because a muscle called the diaphragm moves up and down, helping air get in and out of your lungs.

🎯 Exam Tip: Remember that the diaphragm is the primary muscle responsible for the physical act of breathing.

Question (b) The process of keeping the blood flowing continuously throughout the body
Answer: circulation. This continuous flow ensures that oxygen and nutrients reach every part of the body.
In simple words: Circulation is how your blood keeps moving all over your body, delivering important things everywhere.

🎯 Exam Tip: Understand that circulation is vital for distributing oxygen, nutrients, and removing waste products from the body.

Question (c) Air that enters through the nose and passes into this tube.
Answer: trachea. The trachea, also known as the windpipe, is a vital part of the respiratory system.
In simple words: The trachea is the tube that air goes through after you breathe it in through your nose, leading to your lungs.

🎯 Exam Tip: Know the main parts of the respiratory system and their functions, especially the path air takes into the lungs.

Environmental Studies Part 1 Standard 5th Solutions Chapter 21 Busy At Work – Our Internal Organs Additional Important Questions And Answers

Fill In The Blanks With The Correct Answers From The Options Given Below:

Question 1. The __________ is present between the thoracic cavity and abdominal cavity below the lung.
(a) stomach
(b) diaphragm
(c) heart
Answer: (b) diaphragm
In simple words: The diaphragm is a muscle that separates your chest (where lungs are) from your belly, and it helps you breathe.

🎯 Exam Tip: Remember the diaphragm's location and its crucial role in separating the thoracic and abdominal cavities, as well as its function in respiration.

Question 2. The air sacs formed at the end of the last branches of the trachea are called __________ .
(a) alveoli
(b) thoracic
Answer: (a) alveoli
In simple words: Alveoli are tiny air sacs at the very end of your breathing tubes where oxygen goes into your blood and carbon dioxide leaves.

🎯 Exam Tip: Know the specific names of the structures in the respiratory system, especially the alveoli, which are key for gas exchange.

Question 3. The inner lining of the respiratory organs has the fine hair-like structures called
(a) nose
(b) cilia
(c) alveoli
Answer: (b) cilia
In simple words: Cilia are tiny, hair-like structures that line our breathing tubes and help to sweep out dust and germs, keeping our lungs clean.

🎯 Exam Tip: Remember that cilia are crucial for protecting the respiratory system by trapping and moving foreign particles out of the airways.

Question 4. A layer of sticky substances present in the inner lining of the respiratory organ is known as
(a) mucus
(b) cilia
(c) skin
Answer: (a) mucus
In simple words: Mucus is a sticky fluid that traps dust, pollen, and other small particles, preventing them from reaching your lungs.

🎯 Exam Tip: Understand the combined role of mucus and cilia: mucus traps particles, and cilia move the mucus out of the respiratory tract.

Question 5. Smoking causes life threatning diseases like
(a) lung cancer
(b) asthma
(c) pneumonia
Answer: (a) lung cancer
In simple words: Smoking introduces harmful chemicals into the body, which can damage cells and lead to serious illnesses like lung cancer.

🎯 Exam Tip: When asked about health risks, always link the cause (smoking) to specific, severe effects (like lung cancer) for a complete answer.

Question 6. The process of digestion begins in the
(a) stomach
(b) oesophagus

Question 7. Small intestine of an adult is ................................. long and the large intestine is ................................. long.
(a) 7 mtrs
(b) 1 1/2 mtr
(c) 2 mtrs
Answer: (a) 7 mtrs, (b) 1 1/2 mtr
In simple words: The small intestine is about 7 meters long, and the large intestine is about 1.5 meters long, both playing crucial roles in digestion.

🎯 Exam Tip: Remember the approximate lengths of the small and large intestines as they are common facts in human anatomy questions.

Question 8. ................................. is the hardest substance in our body.
(a) Tooth enamel
(b) Nail
(c) Hair
Answer: (a) Tooth enamel
In simple words: Tooth enamel is the tough outer layer of your teeth, making it the strongest material in the human body, even harder than bone.

🎯 Exam Tip: Knowing the hardest substance in the body is a fundamental biology fact; always associate it with tooth enamel.

Question 9. ................................. is secreted by the salivary glands.
(a) Mucus
(b) Saliva
(c) Cilia
Answer: (b) Saliva
In simple words: Salivary glands produce saliva, which helps moisten food, makes it easier to swallow, and begins the digestion of carbohydrates.

🎯 Exam Tip: Understand the function of salivary glands and their primary secretion, saliva, as it's key to understanding the first step of digestion.

Question 10. It is necessary for the body to get a continuous supply of .................................
(a) oxygen
(b) nitrogen
(c) carbon dioxide
Answer:
In simple words: The body needs a constant supply of oxygen to fuel its cells and carry out all life processes, similar to how a fire needs oxygen to burn.

🎯 Exam Tip: Always remember that oxygen is vital for cellular respiration, which provides energy for all bodily functions.

Question 11. When the diaphragm moves we breathe in.
(a) upward
(b) sideways
(c) downward
Answer: (c) downward
In simple words: When the diaphragm moves downward, it creates more space in your chest, allowing air to rush into your lungs, which is how you breathe in.

🎯 Exam Tip: Remember that the diaphragm's downward movement increases lung volume, leading to inhalation. Upward movement decreases volume, leading to exhalation.

Question 12. The food we eat is in our body.
(a) mixed
(b) churned
(c) digested
Answer: (c) digested
In simple words: Digestion is the process where food is broken down into smaller pieces and nutrients that your body can absorb and use for energy and growth.

🎯 Exam Tip: Digestion is a complex process involving mechanical and chemical breakdown; "digested" is the most comprehensive term for what happens to food in the body.

Question 13. The teeth, tongue and saliva all help to convert food into a soft moist ball called a .
(a) bolus
(b) cilia
(c) saliva
Answer: (a) bolus
In simple words: Before you swallow, your mouth turns food into a soft, easy-to-swallow ball called a bolus, thanks to chewing and mixing with saliva.

🎯 Exam Tip: The term "bolus" specifically refers to the chewed food mixed with saliva, ready for swallowing. Cilia are tiny hair-like structures, and saliva is the liquid itself.

Question 14. As a result of respiration, enters the blood in the body and spreads to all parts of the body.
(a) carbon
(b) sulphur
(c) oxygen
Answer: (c) oxygen
In simple words: During respiration, your body takes in oxygen from the air, which then travels through your blood to power all your body's cells and functions.

🎯 Exam Tip: Respiration is the process of gas exchange where oxygen is taken in and carbon dioxide is released. Oxygen is vital for cellular energy production throughout the body.

Question 15. The process of keeping the blood flowing through all parts of the body is called .......................... circulation.
(a) body
(b) blood
(c) oxygen
Answer: (b) blood
In simple words: The continuous movement of blood throughout the body is known as blood circulation, which is essential for life.

🎯 Exam Tip: Remember that 'circulation' specifically refers to the movement of blood throughout the body, a vital process for delivering oxygen and nutrients.

Question 16. As long as we are alive, the process of blood .......................... goes on continuously, day and night.
(a) respiration
(b) circulation
(c) co-ordination
Answer: (b) circulation
In simple words: The process of blood circulation is constant and never stops, ensuring that blood reaches every part of our body continuously.

🎯 Exam Tip: Understand that blood circulation is a continuous and vital process for life, ensuring oxygen and nutrients reach all parts of the body without interruption.

Question 17. Maintaining the co-ordination of the different functions in the body is the function of the .......................... .
(a) lung
(b) nerves
(c) brain
Answer: (c) brain
In simple words: The brain acts as the central control unit, making sure all the different parts and functions of your body work together in a coordinated way.

🎯 Exam Tip: The brain is the primary organ responsible for coordinating all bodily functions and maintaining overall control and harmony within the body.

Question 18. A network of .......................... carry messages to and fro between the brain and the parts of the body.
(a) nerves

Question 19. The brain and the network of nerves are together called the .................... system.
(a) circulatory
(b) nervous
(c) respiratory
Answer: (b) nervous
In simple words: The brain and all the nerves in your body work together as the nervous system, which controls everything you do and feel.

🎯 Exam Tip: When identifying body systems, remember that the nervous system specifically deals with the brain and nerves, controlling communication throughout the body.

Define The Following Or Explain The Terms

Question 1. System
Answer: A group of organs that carry out similar functions in the body is called a system. These systems work together to keep the body functioning properly.
In simple words: A system is a team of body parts that all do a similar job, like your digestive system breaking down food.

🎯 Exam Tip: When defining biological terms, always include the key components (e.g., "group of organs") and their primary function (e.g., "carry out similar functions").

Question 2. Blood circulation
Answer: The process of keeping the blood flowing through all parts of the body is called blood circulation. This continuous flow is vital for delivering oxygen and nutrients.
In simple words: Blood circulation is how your blood moves all around your body, delivering good stuff and taking away waste.

🎯 Exam Tip: Emphasize the continuous nature and the purpose (delivering nutrients/oxygen) when defining circulation to score full marks.

Question 3. Digestion
Answer: The process of converting food to simpler substances which can get mixed into blood easily is called digestion. This breakdown allows the body to absorb essential nutrients.
In simple words: Digestion is when your body breaks down food into tiny pieces so it can use the nutrients.

🎯 Exam Tip: Focus on the transformation of food ("converting to simpler substances") and the outcome ("mixed into blood easily" or "absorption of nutrients") in your definition.

Question 4. Respiration
Answer: The process of entering of oxygen into the blood, so that it can be used to burn the food and release energy is called respiration. This vital process ensures all body cells receive the energy they need to function.
In simple words: Respiration is how our body takes in oxygen, uses it to burn food for energy, and then releases that energy.

🎯 Exam Tip: When defining biological processes like respiration, always include the key components (oxygen, food, energy release) and the purpose (used by the body).

Question 3. Choose the appropriate word from the brackets:
(constipation, trachea, diaphragm, circulation, breathing, brain, enamel)
1. Maintaining co-ordination between various systems is its function.
2. When there is a tooth decay this is corroded a.
3. The process of inhaling oxygen and exhaling carbon dioxide.
4. Passing hard stool or not passing stool regularly.
Answer:
1. brain
2. enamel
3. breathing
4. constipation
In simple words: This question tests your knowledge of basic body functions and common health terms by asking you to pick the right word from a list for each description.

🎯 Exam Tip: For fill-in-the-blanks from a word bank, read all options first, then match them to the most fitting description. Eliminate options as you use them.

Question (A) Match the columns:

Answer:
1. Mouth - (c) Formation of bolus
2. Stomach - (b) Faeces collected
3. Small intestine - (d) Food absorbed into the blood
4. Large intestine - (a) Excess water present is absorbed
In simple words: This matches each part of the digestive system with its main function, showing how food travels and is processed in the body. Note that while faeces are collected in the large intestine, in a forced matching scenario, the stomach is the only remaining organ to pair with the remaining function.

🎯 Exam Tip: When matching columns, identify the most obvious pairs first. For biological functions, focus on the primary role of each organ. If an option seems less direct, consider it after all clear matches are made.

Question. Match the following:
Answer:

🎯 Exam Tip: When matching columns, draw lines or write the correct pair next to each item to ensure accuracy. Focus on the primary function of each organ.

Question 5. Name the following:
1. An organ that pumps blood continuously.
2. An organ that maintains and co-ordinates the functioning of all the organ systems.
3. An organ that expels4faeces.
4. Organs which are affected by drinking alcohol for a long period of time.
5. A system that gives support and shape to the body.
6. A system that expels the waste substances that are formed in the body.
Answer:
1. Heart
2. Brain
3. Anus
4. Liver and Kidney
5. Skeletal System
6. Excretory System
In simple words: This question asks you to identify specific organs or systems based on their key functions in the human body.

🎯 Exam Tip: For "Name the following" questions, provide concise and accurate names. Ensure you understand the primary function of each body part or system to answer correctly.

Answer in One or Two Sentences

Question 1. Which organ helps us to enjoy many different tastes and flavours while having our meals?
Answer: The tongue and the nose help us to sense the taste and flavours while having our meal. Our sense of smell also plays a crucial role in perceiving flavors.
In simple words: Our tongue helps us taste, and our nose helps us smell, both working together to let us enjoy the different flavors in our food.

🎯 Exam Tip: Remember that both taste (tongue) and smell (nose) are essential for fully experiencing food flavors.

Question 2. Name the organs of the digestive system. (Use your brain power.)
Answer: The organs of the digestive system are mouth, oesophagus, stomach, small intestine, large intestine, rectum, anus and all the other outside glands like salivary glands, liver and pancreas. These organs work together to break down food and absorb nutrients.
In simple words: The digestive system includes the mouth, food pipe, stomach, intestines, and glands like the liver and pancreas, all working to process food.

🎯 Exam Tip: When listing organs of a system, try to remember them in the order food passes through or by their functional groups (main organs vs. accessory glands).

Question 3. In which cavity of the body are the brain, lungs, heart and stomach situated and what is its function?
Answer: The brain is situated in the cranial cavity, the heart and the lung is present the thoracic cavity and the stomach is present in the abdominal cavity. The bones present in the cavity protect these delicate organs from external damage.
In simple words: The brain is in the head cavity, the heart and lungs are in the chest cavity, and the stomach is in the belly cavity; these cavities protect these important body parts.

🎯 Exam Tip: Clearly state the cavity for each organ and then explain the common protective function of these cavities.

Question 4. Which bones protect the brain, heart and lungs and the stomach?
Answer: The brain is protected by the skull, the heart and lungs are protected by rib cage as they are present inside it and the stomach is protected by strong muscles and by the rib cage. The skeletal system provides vital protection for many internal organs.
In simple words: The skull protects the brain, the rib cage protects the heart and lungs, and strong muscles along with the rib cage protect the stomach.

🎯 Exam Tip: Be specific about which bone structure protects which organ (e.g., skull for brain, rib cage for heart/lungs).

Question 5. How is faeces formed?
Answer: When the digested food and water gets absorbed into the blood, and then what remains behind forms the faeces. This waste material is then eliminated from the body.
In simple words: Faeces are formed from the undigested parts of food and water that are left over after the body has absorbed all the nutrients.

🎯 Exam Tip: Remember that faeces are the undigested waste products, not just any waste, and are formed after nutrient absorption.

Question 6. How many times do humans breathe per minute when resting or sitting comfortably?
Answer: A healthy adult breathes 16-20 times per minute whereas a child of 6 months breathes 25-40 times per minutes and a child of 6-10 years breathes 18-25 times per minute. Breathing rates vary significantly with age and activity level.
In simple words: When resting, adults breathe about 16-20 times per minute, while children breathe faster, with rates varying by age.

🎯 Exam Tip: When answering questions about physiological rates, it's good to provide a range and mention how it changes with age or activity if relevant.

Question 7. How many times does one breathe after running a hundred metre race?
Answer: When a person runs a race the breath rate is more than 16-20 times per minute for an adult and more than 18-25 times per minute for a child of 6 -10 years. This increased rate helps the body get more oxygen to recover from exertion.
In simple words: After running, a person's breathing rate increases significantly, becoming much faster than their resting rate, to take in more oxygen.

🎯 Exam Tip: Always explain *why* the breathing rate changes (e.g., for more oxygen) when discussing physical activity.

Give Reasons:

Question 1. Harmful substances like dust, smoke and microorganisms present in the air cannot reach the lungs.
Answer: The inner lining of the nose has thin hair-like structures called cilia. This inner lining also secretes a sticky substance called mucus. The harmful substances like dust, smoke, micro-organisms etc. are filtered by the cilia and they get entangled in the mucus. This then sticks to the inner lining of the nose. The cilia sometimes pushes these substances towards the nostril. This is then blown out by sneezing. Thus the harmful substances are prevented from entering the lungs, protecting the delicate respiratory system.
In simple words: The nose has tiny hairs (cilia) and sticky mucus that trap dust, smoke, and germs, stopping them from reaching the lungs. Sneezing also helps expel these trapped particles.

🎯 Exam Tip: When explaining protective mechanisms, clearly mention the structures involved (cilia, mucus) and their combined function in filtering air.

Question 2. Smoking for a long time reduces the efficiency of the lung.
Answer: When one keeps smoking over a long period of time, the toxic substances in the smoke collect in the respiratory tract. The solid particles in this tobacco smoke form a sticky layer inside the alveoli. As these toxic substances get collected more and more, the exchange of gases like oxygen and carbon dioxide does not take place properly. This gradual build-up significantly impairs the lung's ability to function effectively. Therefore, the efficiency of the lung decreases.
In simple words: Smoking causes harmful substances to build up in the lungs, making it hard for them to exchange oxygen and carbon dioxide properly, which reduces their overall efficiency.

🎯 Exam Tip: When explaining health impacts, describe the mechanism (how it happens) and the direct consequence clearly.

Question 3. It is important to drink adequate quantities of water after eating.
Answer: Water is absorbed through the alimentary canal and used for all processes. If one does not drink enough water digestion cannot take place properly, as food cannot keep moving properly. This will lead to constipation. Also water absorbed is used for the proper functioning of all other body processes. Staying hydrated is crucial for maintaining overall bodily functions beyond just digestion. Therefore, it is important to drink adequate quantity of water.
In simple words: Drinking enough water after eating helps digestion by moving food along and prevents constipation. It also supports many other important body functions.

🎯 Exam Tip: Emphasize the dual role of water in digestion (food movement) and overall body function for a complete answer.

Question 4. We must not eat in a hurry and avoid speaking while eating.
Answer: The upper ends of both the oesophagus and the windpipe open in the throat next to each other. When food is swallowed the wind pipe remains closed. If we eat in a hurry or speak while eating, food may enter the windpipe and cause us to choke. This careful coordination prevents food from entering the respiratory system, which could be dangerous. To avoid this from happening, we must not eat in a hurry or speak while eating.
In simple words: The food pipe and windpipe are close in your throat. Eating fast or talking while eating can make food go down the wrong pipe (windpipe), causing you to choke.

🎯 Exam Tip: Clearly explain the anatomical reason (oesophagus and windpipe proximity) and the direct consequence (choking) for full marks.

Question 5. It is dangerous to drive after drinking alcohol.
Answer: Alcohol affects the nervous system. Hence when one drinks alcohol, one loses control over the movements of the body due to lack of co-ordination. This impaired judgment and reaction time make driving extremely hazardous. Due to lack of co-ordination while driving when many accidents occur on the road, leading to loss of life. Therefore, it is dangerous to drive after drinking alcohol.
In simple words: Alcohol affects your brain and nerves, making you lose control of your body movements and coordination. This makes driving very dangerous and can cause serious accidents.

🎯 Exam Tip: Focus on the impact of alcohol on the nervous system, leading to impaired coordination and the direct link to road accidents.

Use Your Brain Power!

Question 1. Describe which systems work together to provide the body with energy.
Answer: The oxygen present in the inhaled air enters the blood due to the respiratory system. The food is digested and it also enters the blood due to the digestive system. The blood then flows to every part of the body due to circulatory system and it supplies the digested food and oxygen. The food acts as fuel and it bums slowly in presence of oxygen releasing energy. This energy is then used by various parts of the body to do work. Thus the respiratory system, digestive system and circulatory system work together to provide the body with energy. This intricate coordination ensures the body's continuous functioning.
In simple words: The respiratory system brings oxygen, the digestive system processes food, and the circulatory system delivers both to cells, working together to produce energy.

🎯 Exam Tip: When describing system interactions, clearly state the role of each system and how they connect to achieve the overall function, like energy production.

Answer The Following Questions:

Question 1. Describe the process of digestion taking place in the stomach.
Answer: The soft bolus which is swallowed enters the stomach through the oesophagus. Here the food is then churned. The digestive juices mix with this food and bring about some digestive process. At the same time disease producing germs present in the food are destroyed. The food then changes into a thin slurry and passes into the small intestine. This churning action is crucial for breaking down food further.
In simple words: In the stomach, food is churned and mixed with digestive juices, breaking it down and killing germs, before turning into a thin liquid that moves to the small intestine.

🎯 Exam Tip: Remember to mention both the mechanical (churning) and chemical (digestive juices, germ destruction) aspects of digestion in the stomach for a complete answer.

Question 2. How is food absorbed into the blood?
Answer: The thin slurry formed in the stomach enters the small intestine. Many glands like liver, pancreas secrete their digestive juices into the small intestine. These secretions help in the digestive process. As a result of these processes, some substances which can easily mix with the blood are formed. These substances are then absorbed into the blood. The small intestine's structure is perfectly adapted for this absorption.
In simple words: In the small intestine, digestive juices break down food into tiny particles that can pass directly into the bloodstream.

🎯 Exam Tip: Focus on the role of the small intestine and the final breakdown of food into absorbable substances when explaining how nutrients enter the blood.

Question 3. Give the functions of the following system, (a) Skeletal System (b) Nervous System (c) Excretory System.
Answer:
(a) Skeletal System gives support and shape to our body. They also protect the important organs like brain, heart, lungs, etc. present in our body. This system is crucial for maintaining our body's structure and protecting vital internal organs.
(b) Nervous System: It helps to co-ordinate the functions of various systems. Thus it maintains the smooth functioning of all the systems. It acts as the body's communication network, ensuring all parts work together.
(c) Excretory System: It helps to expel the waste produced in our body and helps in keeping us healthy. This process is vital for detoxification and maintaining internal balance.
In simple words: The skeletal system provides structure and protection, the nervous system coordinates body functions, and the excretory system removes waste to keep us healthy.

🎯 Exam Tip: When asked for functions of body systems, always mention their primary role and one key benefit or action they perform.

Question 4. How do we inhale and exhale air?
Answer: When the diaphragm moves down, the air is sucked inside the lung. Thus air is inhaled when diaphragm moves up the air inside the lung is pushed out. Thus the air is exhaled. The up and down movement of the diaphragm causes us to exhale and inhale air, making breathing an involuntary yet vital process.
In simple words: We inhale when the diaphragm moves down, pulling air into the lungs, and exhale when it moves up, pushing air out.

🎯 Exam Tip: Focus on the role of the diaphragm and the direction of its movement in relation to air entering and leaving the lungs.

Question 5. Draw neat and labelled diagram of:
(1) Respiratory system
(2) Digestive system.
Answer: To score full marks, you would need to draw neat and labelled diagrams for both the Respiratory system and the Digestive system. These diagrams should clearly show the main organs and their connections. The key components to label for each system are:
(1) Respiratory system: Lungs, Trachea, Bronchi, Diaphragm, Nasal Passage.
(2) Digestive system: Mouth, Esophagus, Stomach, Small Intestine, Large Intestine, Liver, Pancreas.
In simple words: For this question, you need to draw and label the main parts of the breathing system (like lungs and windpipe) and the food processing system (like stomach and intestines).

🎯 Exam Tip: When asked to draw and label diagrams, ensure your drawing is clear, all major parts are correctly identified, and labels are legible and accurate. Practice drawing these systems regularly.

Respiratory System

• nose
• tracheal windpipe
• lungs
• diaphragm

Digestive System

• mouth
• salivary glands
• liver
• pancreas
• large intestine
• oesophagus /gullet
• stomach
• small intestine
• rectum
• anus

Can You Tell?

Question 1. Name the organs that bring about respiration.
Answer: The organs that help in respiration are, the nose, the trachea or wind pipe, the diaphragm and the lungs. These organs work together to ensure a continuous supply of oxygen to the body.
In simple words: Respiration involves the nose, windpipe, diaphragm, and lungs working together to help us breathe.

🎯 Exam Tip: When listing organs, ensure you include all key components mentioned in the text to score full marks.

Question 2. How do we know that we are hungry and that we should eat?
Answer: When the food absorbed in the blood gets exhausted, after release of energy, the message reaches the brain via the network of nerves. Due to this, the brain then gets the signal that the body needs food. We realise we are hungry and we need to eat food to replenish our energy.
In simple words: Our brain gets a signal through nerves when our body runs out of absorbed food and energy, making us feel hungry.

🎯 Exam Tip: Focus on the role of the brain and the nervous system in signaling hunger for a complete answer.

Question 3. How do the salivary glands come to know that there is food in the mouth and it is time to secrete saliva?
Answer: When we eat food the nerve present in the nose and tongue send the message via the network of nerves to the brain. The brain then sends the message to the salivary gland to secrete the saliva. This is how the salivary glands comes to know that there is food in the mouth and it needs to secrete saliva, aiding in digestion.
In simple words: Nerves in our nose and tongue tell the brain when food is present, and the brain then signals the salivary glands to produce saliva.

🎯 Exam Tip: Remember the sequence: sensory nerves (nose/tongue) -> brain -> salivary glands. This pathway is crucial.

Question 4. What makes respiration and blood circulation go on all the time and the process of digestion happen at the right time?
Answer: Our body needs energy to do work. Due to this our body requires a supply of oxygen continuously. Thus to supply oxygen continuously respiration goes on continuously. To carry oxygen to all the parts of the body continuously blood needs to circulate. Therefore circulation also needs to go on continuously. When energy is released the food absorbed in the blood gets exhausted. Through the network of nerves the brain gets the message and it signals us that we are hungry and we need to eat food, ensuring digestion happens when needed.
In simple words: Respiration and blood circulation are continuous because our body constantly needs oxygen and energy. Digestion happens when the brain signals hunger after energy stores are low.

🎯 Exam Tip: Connect the continuous processes (respiration, circulation) to the body's constant need for oxygen and energy, and link digestion timing to the brain's hunger signals.

Glossary:

1. moist – slightly wet
2. churned – moved vigorously.
3. adequate - acceptable in quantity.
4. corroded – damaged
5. expels - forces out from body.
6. choke - difficulty in breathing
7. secretes -produces and discharges (a substance).
8. slurry – a semi-liquid mixture.