Maharashtra Board Class 7 Science Chapter 12 The Muscular System and Digestive System in Human Beings Solutions

1. Fill In The Blanks With The Right Word From The Brackets:

Question a. The process of digestion starts from the ............... (stomach, mouth).
Answer: mouth
In simple words: Digestion begins in the mouth where food is chewed and mixed with saliva.

🎯 Exam Tip: Remember the mouth is the entry point for food into the digestive system, marking the start of physical and chemical digestion.

Question b. Eyelids have ............... muscles. (voluntary, involuntary)
Answer: involuntary
In simple words: Eyelid movements, like blinking, happen automatically without conscious thought, making them involuntary.

🎯 Exam Tip: Distinguish between voluntary muscles (controlled by will) and involuntary muscles (automatic functions) in the human body.

Question c. ............... is not a function of muscular system. (production of blood cell, performing movement)
Answer: Production of blood cells
In simple words: The muscular system primarily enables movement, while blood cell production occurs in bone marrow.

🎯 Exam Tip: Understand the primary roles of different body systems; the muscular system is for movement, not blood cell formation.

Question d. Muscles of the heart are ............ (ordinary muscles, cardiac muscles)
Answer: cardiac muscles
In simple words: The heart has a unique type of muscle called cardiac muscle, specialized for continuous pumping.

🎯 Exam Tip: Cardiac muscles are distinct from skeletal and smooth muscles due to their involuntary and continuous contractile nature.

Question e. Pushing forward the food that has been chewed is the function of the .................. (stomach, oesophagus)
Answer: Oesophagus.
In simple words: The oesophagus uses wave-like contractions to move food from the mouth down to the stomach.

🎯 Exam Tip: Recognize the role of the oesophagus in peristalsis, the muscular contractions that propel food through the digestive tract.

2. Find A Match For Me:

Question a. Match the following.

Answer:

In simple words: This match identifies key characteristics and functions of different muscle types and digestive components. Cardiac muscles work tirelessly, chewing involves muscle action, pepsin is a digestive enzyme, cramps are painful muscle contractions, and skeletal muscles work in pairs for movement.

🎯 Exam Tip: For 'Match the following' questions, understand the core definition or function of each term to correctly pair them.

3. Who Is Telling A Lie?

Question a. Identify the truthful and false statements regarding body organs.

Answer:
1. Lie. My taste buds can tell all tastes - sweet, sour, bitter.
2. Truth.
3. Lie. It is 1.5 metre long.
4. Truth.
5. Lung - Lie. It plays important role in breathing.
In simple words: This question tests knowledge about the specific functions and characteristics of various organs, identifying common misconceptions.

🎯 Exam Tip: Pay close attention to details about organ functions and dimensions to determine accuracy in 'True or False' or 'Who is telling a lie?' questions.

4. Give Reasons:

Question 1. Food becomes acidic in the stomach.
Answer:
1. The gastric glands of stomach secrete gastric juice.
2. Food that has entered stomach is churned.
3. Three components of gastric juice namely hydrochloric acid, pepsin and mucus are mixed with food here and the food becomes acidic.
In simple words: The stomach produces hydrochloric acid as part of its gastric juice, which mixes with food, making it acidic to aid digestion and kill bacteria.

🎯 Exam Tip: Remember that hydrochloric acid in the stomach is crucial for activating pepsin and providing an optimal environment for protein digestion.

Question 2. Cardiac muscles are said to be involuntary muscles.
Answer:
1. Cardiac muscles are found in the heart.
2. These muscles bring about the contraction and relaxation (beating) of the heart.
3. Their movement is involuntary.
4. Cardiac muscles cause our heart to relax and contract continuously at a rate of about 70 times per minute. They do not depend upon our will.
5. Beating is carried out in their own fixed manner.
So cardiac muscles are said to be involuntary muscles.
In simple words: Cardiac muscles work automatically and continuously to pump blood throughout the body, without conscious control, hence they are involuntary.

🎯 Exam Tip: Highlight the continuous, autonomous function of cardiac muscles, essential for life, which differentiates them from voluntary skeletal muscles.

Question 3. Intoxicating substances should not be consumed.
Answer:
1. Physical health is important for our organ system to function properly.
2. But harmful habits like smoking, chewing of tobacco, drinking alcohol affect our health adversely.
3. If we consume any tobacco products, the mouth, pharynx, alimentary canal, and other organs of the digestive system cannot function properly.
4. It causes problems like vomiting, nausea, and headache.
5. Tobacco particles stick to teeth, gums, and skin of the mouth cavity and slowly cause injury to those parts resulting in their dysfunction.
6. This causes swelling of the gums and pain when moving the jaws.
7. The pharynx and intestine become inflamed it progress into cancer leading to death.
In simple words: Intoxicating substances harm organ systems, especially the digestive system, leading to various health problems and increasing the risk of serious diseases like cancer.

🎯 Exam Tip: Emphasize the long-term, detrimental effects of intoxicating substances on multiple body systems, particularly the increased risk of cancer and organ dysfunction.

Question 4. Your muscles should be strong and efficient.
Answer:
Muscles are bundles of fibres that can contract and relax as required.
1. The action of muscles is necessary for all kinds of movements from the small movements of eyelid to those that demand great strength when chopping wood with an axe.
2. We use muscles for various movements like talking laughing, walking, jumping, throwing etc.
3. Therefore our muscles should be strong and efficient to do our day-to-day work well and smooth functioning of life processes.
In simple words: Strong and efficient muscles are vital for performing daily activities, from small movements to strenuous tasks, ensuring overall body function and smooth execution of life processes.

🎯 Exam Tip: Connect muscle strength and efficiency to daily functionality and the overall health and proper working of the body's systems.

5. Answer The Following:

Question a. How many types of muscles are there? Which are those types?
Answer:
Muscles are bundles of fibres that can contract and relax as required. There are three types of muscles.
• Skeletal muscles.
• Heart or cardiac muscles.
• Smooth muscles.
In simple words: There are three main types of muscles in the human body: skeletal muscles for voluntary movement, cardiac muscles for heart contractions, and smooth muscles for involuntary organ functions.

🎯 Exam Tip: Clearly define each muscle type and provide an example to illustrate its function and control mechanism (voluntary/involuntary).

Question b. What causes the problem of acidity? What is its effect on the body?
Answer:
1. Stress is the main cause of acidity.
2. Hectic lifestyle and stress can lead to unhealthy or irregular meals, not good for digestion process, and this may cause acidity.
3. Other reasons are eating spicy food, drinking too much alcohol, missing meals, an empty stomach may lead to acidity.
4. Acidity leads to stomach upset, burning sensation in chest and stomach, constriction of blood vessels, weight gain, obesity, cardiovascular damage.
In simple words: Acidity is primarily caused by stress, irregular meals, and unhealthy dietary habits like spicy food and alcohol, leading to symptoms like stomach upset, burning sensations, and potential long-term cardiovascular damage.

🎯 Exam Tip: When discussing acidity, link causes like stress and diet to specific physiological effects on the digestive and cardiovascular systems.

Question c. Name the different types of teeth. What is the function of each type?
Answer:
There are four types of teeth, namely incisors, canines, pre-molars, and molars.
1. Incisors: (a) These come in first 6-months of age. Incisors are the eight teeth in the front and centre four on top and four on bottom, (b) They are sharp and blade-like for cutting food. e.g. for biting an apple, (c) We use them to take first bite of food.
2. Canines: (a) These are strong and pointed, sharpest of all for tearing food. e.g. to tear off a piece of tough meat, (b) They play important role in digestion of food, (c) They appear between 11 and 20 months of age.
3. Pre-molar: Pre-molar share features of both canines and molars. (a) You can use them for grinding and chewing food. So that it becomes semi-liquid helping to gulp down the throat easily, (b) They are situated at each side of your mouth in deep settings, (c) They appear at the age of 10 years.
4. Molar: (a) These are broad and flat on top for crushing and grinding food. e.g. to grind up nutmeats. (b) Two teeth above and two below, they appear at the age 11-13 years. (c) Molars are more prone to germ attack because of their remote location in our mouth.
So we should keep them clean.
In simple words: Teeth are categorized into incisors (for cutting), canines (for tearing), premolars (for grinding), and molars (for crushing), each playing a specialized role in breaking down food for digestion.

🎯 Exam Tip: When describing teeth types, include their specific shape, location, primary function, and general age of appearance for a comprehensive answer.

6. Sketch And Label A Diagram Of The Digestive System And Describe It In Your Own Words:

Question a. Sketch and label a diagram of the digestive system and describe it in your own words.
Answer:

ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र मानव पाचन तंत्र की संरचना को दर्शाता है, जिसमें भोजन नली (oesophagus), यकृत (liver), अग्न्याशय (pancreas), पेट (stomach), छोटी आंत (small intestine), और बड़ी आंत (large intestine) जैसे प्रमुख अंग शामिल हैं। यह विभिन्न पाचक ग्रंथियों जैसे लार ग्रंथियों को भी दिखाता है जो पाचन प्रक्रिया में सहायक होती हैं।
1. Conversion of food into a soluble form and its absorption into the blood is called digestion.
2. The digestive system consists of the alimentary canal and digestive glands.
3. The total length of alimentary canal is about 9 metres.
4. Its main parts are the mouth, pharynx, oesophagus, stomach, small intestine, large intestine, rectum and anus.
5. The salivary glands, liver, pancreas are the digestive glands connected to the alimentary canal.
6. Different organs of the digestive system perform the function of digestion.
7. There are different stages in the process of digestion of food.
8. The process of digestion begins with the function of the teeth in the mouth, food is chewed into small pieces.
9. There are four types of teeth, incisors, canines, pre-molars and molars.
10. Saliva in the mouth contains enzymes, ptyalin, or amylase. It converts starch into maltose.
(a) Oesophagus:
1. It is a tube leading from the pharynx to the stomach,
2. It pushes the food towards the stomach.
(b) Stomach:
1. The large sac like part of the alimentary canal is called the stomach.
2. Food that has entered is churned.
3. The gastric glands of stomach secrete gastric juice which contain hydrochloric acid, pepsin and mucus.
4. They mix with food and food becomes acidic.
5. Mainly proteins are digested in stomach.
6. Due to the churning and actions of gastric juice, food become a semi-solid slurry which is pushed into the small intestine.
(c) Small intestine: (6m long)
1. Bile secreted by liver mixes with food in small intestine,
2. Most of the digestion and absorption of food takes place here.
(d) Large intestine: (1.5m long) only water is absorbed in the large intestine. Undigested remain is thrown out of the body through the anus.
In simple words: The digestive system processes food from the mouth through the oesophagus, stomach, small intestine, and large intestine, where different organs contribute to breaking down food, absorbing nutrients, and eliminating waste.

🎯 Exam Tip: Be able to describe the path of food through the digestive system, detailing the key processes occurring in each major organ like peristalsis in the oesophagus, churning in the stomach, and absorption in the small and large intestines.

Project:

Question 1. Make charts about maintaining good health.
Answer: This is a project-based question designed for student activity. No direct answer is provided here.
In simple words: Students are tasked with creating visual aids (charts) to educate others on practices that promote good health, covering topics like balanced diet, exercise, and hygiene.

🎯 Exam Tip: For project questions, focus on presenting clear, concise information visually, using appropriate illustrations and bullet points for maximum impact and easy understanding.

Question 2. Design a power point presentation about the digestive system and present it in the class.
Answer: This is a project-based question designed for student activity. No direct answer is provided here.
In simple words: Students need to develop a presentation that explains the human digestive system, requiring research, organization, and public speaking skills to deliver the content effectively.

🎯 Exam Tip: When preparing presentations, organize content logically, use clear diagrams, and practice delivery to ensure a smooth and informative session.

Choose And Write The Correct Word:

Question 1. The structure that connects bones to the muscles is the ...............
(a) ligament
(b) tendon
(c) fascicle
(d) skin
Answer: (b) tendon
In simple words: Tendons are strong, fibrous tissues that connect muscles to bones, facilitating movement by transmitting muscle force to the skeletal system.

🎯 Exam Tip: Differentiate between tendons (muscle to bone) and ligaments (bone to bone) as a common point of confusion in anatomy questions.

Question 2. ............... is not performed by muscles.
(a) Motion
(b) Excretion
(c) Maintenance of posture
(d) Heat production
Answer: (d) Heat production
In simple words: While muscles are crucial for motion, posture, and generate heat, excretion is primarily the function of the excretory system, not muscles.

🎯 Exam Tip: Understand the primary functions of muscles (movement, posture, heat generation) and distinguish them from functions of other organ systems, like excretion.

Question 3. Approximately ............... skeletal muscles are there in the human body.
(a) 1000
(b) 600
(c) 100
(d) 60
Answer: (b) 600
In simple words: The human body contains roughly 600 skeletal muscles, which work with bones to enable voluntary movements.

🎯 Exam Tip: Memorize key numerical facts about the human body, such as the approximate number of skeletal muscles, as they are often tested directly.

Question 4. Most of the fat digestion occurs in ...............
(a) rectum
(b) stomach
(c) small intestine
(d) large intestine
Answer: (c) small intestine
In simple words: The majority of fat digestion, aided by bile and pancreatic lipase, takes place in the small intestine.

🎯 Exam Tip: Identify the small intestine as the primary site for the digestion and absorption of most nutrients, including fats, proteins, and carbohydrates.

Question 5. Protein digestion is accomplished in ...............
(a) stomach
(b) ileum
(c) rectum
(d) duodenum
Answer: (b) ileum
In simple words: While protein digestion begins in the stomach, its significant completion and absorption occur in the small intestine, specifically the ileum.

🎯 Exam Tip: Understand that digestion is a multi-stage process, with different nutrients being primarily broken down or absorbed in specific parts of the digestive tract.

Question 6. The main function of the muscular system is ...............
(a) excretion
(b) digestion
(c)movement
(d) contraction
Answer: (c)movement
In simple words: The muscular system's primary role is to enable movement, both voluntary and involuntary, throughout the body.

🎯 Exam Tip: Focus on the overarching role of each body system; for the muscular system, movement is the most fundamental function.

Question 7. The largest muscle of our body is in the ...............
(a) arm
(b) face
(c) thigh
(d) None
Answer: (c) thigh
In simple words: The gluteus maximus, located in the thigh/buttocks region, is generally considered the largest muscle in the human body.

🎯 Exam Tip: Remember specific anatomical facts like the largest muscle, as they are often direct recall questions.

State Whether True Or False. Correct The False Statement And Rewrite:

Question 1. Saliva is mixed with food in the mouth.
Answer: True.
In simple words: Saliva is indeed mixed with food in the mouth, initiating chemical digestion and lubricating food for swallowing.

🎯 Exam Tip: Understand the dual role of saliva in both mechanical (lubrication) and chemical (enzyme action) digestion in the mouth.

Question 2. Gastric juice makes food alkaline.
Answer: False. Gastric juice makes food acidic.
In simple words: Gastric juice, containing hydrochloric acid, makes food highly acidic in the stomach, not alkaline.

🎯 Exam Tip: Clearly differentiate between acidic and alkaline environments in the digestive system and the specific juices responsible for each.

Question 3. Pancreas is the largest gland in the body.
Answer: False. Liver is the largest gland in the body.
In simple words: The liver is the largest gland in the body, performing numerous vital functions, while the pancreas is a significant, but smaller, gland.

🎯 Exam Tip: Know the largest organs and glands in the body, as these are common factual questions.

Question 4. Food becomes acidic in stomach.
Answer: True
In simple words: Food becomes acidic in the stomach due to the secretion of hydrochloric acid by the stomach lining.

🎯 Exam Tip: Reiterate the function of hydrochloric acid in the stomach, which is to create an acidic environment essential for protein digestion.

Question 5. Cardiac muscles are said to be voluntary muscles.
Answer: False. Cardiac muscles are involuntary.
In simple words: Cardiac muscles are involuntary, meaning they contract and relax without conscious thought or control, ensuring the heart continuously pumps blood.

🎯 Exam Tip: Emphasize that cardiac muscle function is entirely involuntary, critical for the automatic beating of the heart.

Question 6. Muscles contribute 60% of the weight of a healthy adult human body.
Answer: False. Muscles contribute almost 40% of the weight of a healthy adult human body.
In simple words: Muscles constitute approximately 40% of an adult human's body weight, not 60%.

🎯 Exam Tip: Pay attention to percentage-based facts; a common mistake is exaggerating the proportion of muscle mass in the body.

Question 7. There are about 30 muscles in the human face.
Answer: True
In simple words: The human face contains approximately 30 muscles, which enable various expressions and movements.

🎯 Exam Tip: Recognize the complexity of facial musculature and its role in human expression and communication.

Question 8. Muscles in our arms and legs have involuntary muscles.
Answer: False. Muscles in our arm and legs are voluntary muscles.
In simple words: Arm and leg muscles are voluntary, meaning their movements are consciously controlled by an individual.

🎯 Exam Tip: Clearly distinguish voluntary muscles (like those in limbs) from involuntary muscles (like heart or digestive organ muscles).

Question 9. Functions of organs like stomach, intestine, heart are carried out by voluntary muscles.
Answer: False. Functions of these organs are carried out by involuntary muscles.
In simple words: Organs such as the stomach, intestine, and heart operate via involuntary muscles, functioning automatically without conscious control.

🎯 Exam Tip: Reinforce the distinction between voluntary muscles (under conscious control) and involuntary muscles (operating autonomously) and their respective locations.

Question 10. Smooth muscles are involuntary muscles.
Answer: True.
In simple words: Smooth muscles, found in internal organs, are indeed involuntary, controlling processes like digestion and blood flow without conscious effort.

🎯 Exam Tip: Remember that smooth muscles are one of the three muscle types and are characterized by their involuntary function.

Question 11. The digestive function of the liver is to produce bile.
Answer: True.
In simple words: The liver's crucial digestive role involves producing bile, which aids in the digestion and absorption of fats in the small intestine.

🎯 Exam Tip: Highlight the liver's role in digestion, specifically bile production, as distinct from its other metabolic functions.

Question 12. The muscular tissue has the ability to contract or shorten.
Answer: True.
In simple words: The fundamental property of muscular tissue is its ability to contract and shorten, which generates force and movement.

🎯 Exam Tip: Understand that contractility is the defining characteristic of muscle tissue, enabling all its various functions.

Find A Match For Me:

Question 1. Match the following.

Answer:

In simple words: This match connects digestive glands and organs with their primary functions, such as salivary glands aiding carbohydrate digestion and the stomach making food acidic.

🎯 Exam Tip: When matching, clearly understand the specific role of each gland or organ in the digestive and metabolic processes.

Question 2. Match the following.

Answer:

In simple words: This matching exercise correctly identifies that saliva lubricates food and contains ptyalin, stomach produces gastric juice, and the gall bladder stores bile.

🎯 Exam Tip: Clearly associate each digestive fluid with its source and key components (like enzymes) or primary function.

Question 4. Match the following.

Answer:

In simple words: This matching helps distinguish muscle types by their location: cardiac muscles are in the heart, skeletal muscles attach to bones, and smooth muscles are found in internal organs like the stomach.

🎯 Exam Tip: For muscle classification, clearly remember the location and primary function of cardiac, skeletal, and smooth muscles.

Question 4.

Answer:

In simple words: This question asks to match different types of muscles with their correct locations or characteristics, illustrating where each muscle type is found in the human body.

🎯 Exam Tip: Understanding the location and function of each muscle type is crucial. Focus on memorizing which muscles are voluntary/involuntary and their primary roles.

Find The Odd Man Out:

Question 1. Stomach, esophagus, liver, small intestine, rectum
Answer: Liver which is a gland and others are parts of digestive tract.
In simple words: The liver is different from the other listed organs because it's a gland that produces substances for digestion, while the others are direct components of the alimentary canal.

🎯 Exam Tip: For "odd one out" questions, identify the common characteristic among most items and then find the one that doesn't share that trait. Classifying organs by function (gland vs. canal) is key here.

Question 2. Saliva, bile, pancreatic juice, gastric juice chyme
Answer: Chyme, it is a liquid food others are digestive juices.
In simple words: Chyme is partially digested food, whereas saliva, bile, pancreatic juice, and gastric juice are all fluids secreted by digestive glands to help break down food.

🎯 Exam Tip: Distinguish between substances that are digestive secretions (juices) and the actual food material at various stages of digestion. This helps in understanding the digestive process.

Name The Following:

Question 1. Gastric juices in stomach
Answer: Hydrochloric acid, Pepsin, Mucus.
In simple words: The stomach produces hydrochloric acid to kill germs and activate enzymes, pepsin to start protein digestion, and mucus to protect the stomach lining.

🎯 Exam Tip: Remember the three main components of gastric juice and their specific functions to score well on questions about stomach digestion.

Question 2. Juices secreted by liver
Answer: Bile.
In simple words: The liver secretes bile, a digestive fluid that helps in the breakdown and absorption of fats in the small intestine.

🎯 Exam Tip: The liver's role in producing bile for fat digestion is a key concept; remember that bile emulsifies fats, making them easier to digest.

Question 3. Pancreatic juices.
Answer: Trypsin, Lipase, Amylase.
In simple words: Pancreatic juice contains enzymes like trypsin for proteins, lipase for fats, and amylase for carbohydrates, digesting all major food types.

🎯 Exam Tip: The pancreas is vital for secreting enzymes that digest proteins, fats, and carbohydrates, making it a central organ in chemical digestion.

Question 4. Salivary gland secretion.
Answer: Saliva
In simple words: Salivary glands produce saliva, which moistens food and begins carbohydrate digestion with enzymes.

🎯 Exam Tip: Remember that saliva initiates mechanical and chemical digestion in the mouth, primarily breaking down starches.

Question 5. Enzyme present in saliva.
Answer: Ptyalin or Amylase.
In simple words: Ptyalin, also known as salivary amylase, is the enzyme in saliva that starts the chemical digestion of carbohydrates in the mouth.

🎯 Exam Tip: Knowing the specific enzyme (ptyalin/amylase) and its substrate (starch/carbohydrates) is crucial for understanding oral digestion.

Question 6. Types of muscles.
Answer: Skeletal, Cardiac and Smooth muscles.
In simple words: There are three main types of muscles: skeletal muscles for voluntary movement, cardiac muscles for heart contractions, and smooth muscles for involuntary organ functions.

🎯 Exam Tip: Be able to list and briefly describe the characteristics (voluntary/involuntary, location) of each of the three muscle types.

Question 7. Study of muscles.
Answer: Myology
In simple words: Myology is the specific branch of biology dedicated to the study of muscles, including their structure, function, and diseases.

🎯 Exam Tip: Familiarity with scientific terminology, like "myology" for the study of muscles, is important for precise communication in biology.

Give Scientific Reason:

Question 1. Skeletal muscles give shape to our body.
Answer: 1. Skeletal muscles are voluntary muscles. The two ends of each of these muscles are attached to two different bones. 2. Muscles of the arms and legs are skeletal muscles. 3. They are responsible for holding the bones of the skeleton together and giving shape to our body.
In simple words: Skeletal muscles attach to bones and work with the skeleton to provide structure, support, and the overall form of our body. Their connection to bones allows them to influence body posture and movement.

🎯 Exam Tip: When explaining the role of skeletal muscles, highlight their attachment to bones, their voluntary nature, and their dual function of providing shape and enabling movement.

Question 2. The process of digestion begins in the mouth.
Answer: 1. The process of digestion begins with the function of the teeth. 2. There are 4 types of teeth - incisors, canines, pre-molar, and molar. 3. They are responsible for grinding the food. 4. Saliva present in the mouth mixes with the food and makes it soft. 5. An enzyme present in saliva called ptyalin amylase converts starch into maltose. Thus, the process of digestion begins in the mouth.
In simple words: Digestion starts in the mouth as teeth mechanically break down food, and saliva, containing enzymes like ptyalin (amylase), chemically begins to break down starches, making the food soft for swallowing.

🎯 Exam Tip: Emphasize both mechanical (teeth) and chemical (saliva/ptyalin) aspects of digestion in the mouth. Mentioning the specific enzyme and its target (starch) is important.

Question 3. Metabolic processes are impossible without enzymes.
Answer: 1. Enzymes are substances secreted in the body of an organism which bring about specific chemical reactions. 2. Enzymes are specific type of proteins. They are most active at normal body temperature. 3. Digestion enzymes of the digestive system bring about changes in the food material. 4. Food is digested with the help of enzymes and converted into more soluble and simple form.
In simple words: Enzymes are biological catalysts that speed up and regulate nearly all chemical reactions in the body, including digestion and energy production. Without them, these essential metabolic processes would be too slow to sustain life.

🎯 Exam Tip: Define enzymes as biological catalysts (proteins), state their role in specific chemical reactions, and explain how they facilitate the breakdown of complex food into simpler, absorbable forms for metabolism.

Write Short Notes On:

Question 1. Voluntary muscles
Answer: 1. Working with our hands, walking, eating are functions that depend upon our will. 2. Muscles used in these actions are called voluntary muscles, e.g. skeletal muscles are voluntary muscles.
In simple words: Voluntary muscles are those we can consciously control, such as the skeletal muscles in our arms and legs, allowing us to perform actions like walking, lifting, or eating.

🎯 Exam Tip: Clearly define voluntary muscles by their characteristic of being under conscious control and provide common examples like skeletal muscles for movement.

Question 2. Involuntary muscles
Answer: 1. Various processes like breathing, blood circulation, digestion are vital function, essential for life. 2. They do not depend upon our will. 3. The muscles of organs which carry out these involuntary functions are called involuntary muscles. 4. Functions of organs like the stomach, intestine, heart are carried out in their own fixed manner by involuntary muscles, e.g. cardiac muscle present in heart, smooth muscles in lining of stomach, small intestine, blood vessel, uterus.
In simple words: Involuntary muscles, like those in the heart, stomach, and blood vessels, operate without our conscious control, performing essential life-sustaining functions such as breathing, blood circulation, and digestion automatically.

🎯 Exam Tip: Focus on the unconscious control aspect of involuntary muscles and provide diverse examples from different body systems (cardiac, smooth) to illustrate their widespread importance for life processes.

Question 3. Muscle and its types
Answer: There are three types of muscles in body 1. Skeletal Muscles 2. Cardiac Muscles 3. Smooth Muscles
In simple words: Muscles are tissues that allow movement, and they are broadly classified into three types: skeletal (voluntary movement), cardiac (heart's involuntary pumping), and smooth (involuntary organ functions).

🎯 Exam Tip: When asked about muscle types, list all three and briefly explain their primary function and whether they are voluntary or involuntary. This demonstrates comprehensive knowledge.

Question 4. Digestive glands
Answer: The salivary glands, liver and pancreas are the digestive glands connected to the alimentary canal. 1. Salivary glands: (a) Saliva is produced in the salivary glands in the mouth cavity, located in front of the ears, below the tongue, (b) It is carried to the mouth via ducts, (c) It is mixed with food during the process of chewing. 2. Saliva: contains an enzyme called Ptyalin or salivary amylase. Ptyalin convdrtfe starch into a sugar called maltose. 3. Liver: (a) The liver is the largest gland in the body, (b) Main function is storage of glucose, (c) The digestive juice secreted by the liver is bile, (d) Bile is carried into small intestine, it mixes with food and helps in digestion of fats. 4. Pancreas: The pancreas secretes the pancreatic juice that contains various enzymes

• Trypsin → converts proteins into amino acids.
• Lipase → converts fats into fatty acids, glycerol
• Amylase → converts complex carbohydrate into simple sugar

In simple words: Digestive glands like salivary glands, liver, and pancreas produce essential juices containing enzymes (e.g., ptyalin, bile, trypsin, lipase, amylase) that chemically break down food into simpler forms for nutrient absorption.

🎯 Exam Tip: To answer questions about digestive glands, list the main glands, describe their secretions, and specify which types of food molecules (carbohydrates, proteins, fats) each enzyme helps to digest.

Question 5. Enzymes
Answer: Enzymes are substances secreted in the body an organism which bring about specific chemical reactions. 1. Metabolic processes are impossible without enzymes. 2. Digestive exzymes of the digestive system bring about changes in the find material. 3. They break down the food into simple form. 4. They are a type of protein. 5. Saliva contain pytalin which converts starch into maltose.

• Trypsin: Convert proteins into amino acids.
• Lipase: Convert fats into fatty acid.
• Amylase: Converts complex carbohydrates into simple sugar.

In simple words: Enzymes are proteins acting as catalysts that enable and speed up vital chemical reactions in the body, such as breaking down food into absorbable nutrients, making life processes possible.

🎯 Exam Tip: Highlight that enzymes are proteins, act as catalysts for specific reactions, are crucial for metabolic processes like digestion, and break complex molecules into simpler forms. Providing specific examples like trypsin, lipase, and amylase strengthens the answer.

Question 6. Draw the structure of the different layers of the tooth.
Answer:
ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र एक दाँत की आंतरिक संरचना को दर्शाता है, जिसमें सबसे बाहरी परत 'एनामेल' (Enamel), उसके नीचे 'डेंटिन' (Dentine), दाँत के चारों ओर 'गम' (Gum), जड़ में 'रूट' (Root), और दाँत को सहारा देने वाली 'बोन' (Bone) को स्पष्ट रूप से लेबल किया गया है। यह दाँत की विभिन्न परतों को दर्शाता है।
In simple words: The tooth structure consists of multiple layers, including the outermost hard enamel, the underlying dentin, the soft pulp inside, and the root embedded in the jawbone and covered by gum.

🎯 Exam Tip: For diagram-based questions, accurately draw and label all key parts. Understand the function of each layer of the tooth to enhance your description.

Differentiate Between:

Question 1. Voluntary and Involuntary muscles.
Answer:

In simple words: Voluntary muscles are those we can control intentionally (like moving our arm), while involuntary muscles function automatically without conscious thought (like our heart beating or digestion).

🎯 Exam Tip: When differentiating, clearly state the key contrasting features like conscious control, location, and examples. Using a table helps in presenting a clear and organized comparison.

Question 2. Skeletal muscle and Cardiac muscle.
Answer:

In simple words: Skeletal muscles are voluntary muscles attached to bones, enabling body movement and giving shape, while cardiac muscles are involuntary, found only in the heart, and responsible for pumping blood throughout the body.

🎯 Exam Tip: Differentiate these two muscle types by focusing on their voluntary/involuntary nature, specific locations, and primary functions. Remember that cardiac muscle is unique to the heart.

Answer The Following:

Question 1. What is meant by organ system?
Answer: 1. There are different structural organizational levels in living organism. 2. Cells → tissues → organ → organ system → organism 3. Different organs together form one organ system.
In simple words: An organ system is a group of different organs that work together to perform specific functions necessary for the survival of an organism, like the digestive system or circulatory system.

🎯 Exam Tip: Explain an organ system by defining it as a collection of interdependent organs working collectively, and illustrate the hierarchy of biological organization from cells to the organism.

Question 2. How are the bones in our body joined to each other?
Answer: Skeleted muscles join two bones with the help of tendons.
In simple words: Bones are primarily joined to each other through ligaments, which connect bone to bone, and by tendons, which connect muscles to bones, facilitating movement.

🎯 Exam Tip: Differentiate between ligaments (bone to bone) and tendons (muscle to bone) when explaining how bones are connected and how movement is facilitated in the skeletal system.

Can You Tell? Answer The Following Questions:

Question 1. What is the mutual relationship between muscles and bones?
Answer: 1. Muscles are firmly attached to bones by means of tendons. 2. When muscles contract there is movement at the joint and there is pull on tendon which in turn pull on the bones to which they are attached.
In simple words: Muscles and bones work together as a musculoskeletal system; muscles contract and pull on tendons, which are attached to bones, causing the bones to move at joints.

🎯 Exam Tip: Explain the muscle-bone relationship by focusing on tendons as the connecting tissue and muscle contraction as the force generating bone movement at joints.

Question 2. Are the muscles of the different organs in our body identical?
Answer: No, muscles of the different organs are not identical, some are voluntary, some are involuntary.
In simple words: The body has different types of muscles (skeletal, cardiac, smooth) with distinct structures and functions, making them non-identical; some are voluntary, and others are involuntary.

🎯 Exam Tip: When discussing muscle types, emphasize that their structure and control (voluntary vs. involuntary) vary depending on the organ and its specific function.

Question 3. How do muscles perform their functions?
Answer: 1. Muscles in our body always work in groups. 2. When some muscles contract other muscles of the same group relax. 3. This is how muscles help in proper performance of the various functions of own body.
In simple words: Muscles perform their functions by working in opposing groups: one set contracts to create movement, while another set relaxes, allowing controlled and coordinated actions.

🎯 Exam Tip: Highlight the principle of antagonistic muscle pairs (contraction/relaxation) and their coordinated action for efficient body movement and function.

Answer The Following Questions:

Question 1. Which parts of our body are made up only of muscles?
Answer: Tongue, heart, stomach, liver, pancreas, intestines are made up of only muscles.
In simple words: Organs like the tongue, heart, stomach, liver, pancreas, and intestines are primarily composed of muscle tissue, enabling their specific movements and functions within the body.

🎯 Exam Tip: Identify organs that rely heavily on muscle tissue for their function, particularly those involved in involuntary actions or movement without skeletal attachment.

Question 2. What would happen if the cardiac muscles do not move?
Answer: 1. Cardiac muscles cause our heart to relax and contract continuously at a rate of about 70 times per minute. 2. These muscles bring about the contraction and relaxation (beating) of the heart. 3. If the cardiac muscles do not move, heart will stop beating, and will not pump blood to other parts of the body and person will die.
In simple words: If cardiac muscles stop moving, the heart would cease to beat, stopping blood circulation and preventing oxygen and nutrients from reaching the body's tissues, which would lead to death.

🎯 Exam Tip: Emphasize the critical role of cardiac muscle contraction in maintaining blood circulation and highlight the dire consequences (cessation of life) if this function fails.

Question 3. Food enters the stomach and the stomach muscles do not move.
Answer: 1. Smooth muscles are present in the lining of stomach. 2. Their movement is responsible for churning of food. 3. If the muscles do not move, food will not be digested.
In simple words: If the smooth muscles in the stomach lining didn't move, food wouldn't be churned and mixed with digestive juices, making proper digestion impossible.

🎯 Exam Tip: Understand the role of smooth muscles in the stomach for mechanical digestion (churning) and how this action is essential for the chemical breakdown of food.

Question 4. During digestion does all the food that we have eaten get converted into useful nutritive substances?
Answer: 1. During digestion not all the food is converted into useful nutritive substance, only whatever nutrients we obtain by digestion of food gets absorbed into the blood in small intestine. 2. Undigested remains of the food enters the large intestine and thrown out of the body through the anus.
In simple words: No, not all food is converted; only the digestible nutrients are absorbed, while the indigestible parts are eliminated from the body as waste.

🎯 Exam Tip: Distinguish between digestion and absorption, noting that only a portion of food is converted into absorbable nutrients, with the rest being expelled as waste.