The Muscular System and Digestive System in Human Beings | Class 7 | Science | Chapter 12 | Maharashtra State Board
Explore the intricate workings of the human body with our YouTube channel! Dive into the Muscular System and Digestive System, unravelling the complexities of muscles, including voluntary and involuntary types. Learn about the crucial roles of skeletal, cardiac, and smooth muscles. Journey through the digestive system, from the mouth to the large intestine, understanding the functions of organs, enzymes, and glands. Discover the impact of lifestyle choices on health, exploring the effects of tobacco, alcohol, and smoking on the digestive system. Join us for insightful content on anatomy, physiology, and how to prioritize your health!
Questions & Answers
1. Fill in the blanks with the right word from the brackets:
(a) The process of digestion starts from the mouth. (stomach, mouth).
(b) Eyelids have involuntary muscles. (voluntary, involuntary)
(c) Production of blood cells is not a function of muscular system. (production of blood cell, performing movement)
(d) Muscles of the heart are cardiac muscles. (ordinary muscles, cardiac muscles)
(e) Pushing forward the food that has been chewed is the function of the Oesophagus.(stomach, oesophagus)
2. Find a match for me.
(a) Ans.
| Coloumn 'A' | Column 'B' |
1. | Cardiac muscle | b. We never feel tired |
2. | Are brought about by muscle | a. Always functions in pairs |
3. | Pepsin | e. Enzymes of the gastric juice |
4. | Cramps | c. Uncontrolled and painful contraction of muscles |
5. | Skeletal muscles | d. Chewing movement of the jaw |
3. Who is telling a lie?
Ans.
| Organ | Lie or Truth | Statement |
1. | Tongue | Lie | My taste buds can tell all tastes – sweet sour, bitter. |
2. | Liver | Truth | I am the largest gland in the body. |
3. | Large intestine | Lie | I am 1.5 metre long. |
4. | Appendix | Truth | Digestion is impossible without me. |
5. | Lung | Lie | I play an important role in breathing. |
4. Give reasons.
1. Food becomes acidic in the stomach. Ans. Food becomes acidic in the stomach because the stomach produces hydrochloric acid (HCl) and pepsin, which lower the pH level of the food and turn it into an acidic environment. This acidic environment helps break down proteins and fats in the food we eat, making them easier to digest.
2. Cardiac muscles are said to be involuntary muscles. Ans. Cardiac muscles are considered involuntary because they contract and pump blood rhythmically and continuously without conscious control. The heartbeat and contraction of the heart muscle are regulated by the cardiac conduction system and the autonomic nervous system, allowing for the automatic and involuntary function of the heart to maintain blood circulation throughout the body.
3. Intoxicating substances should not be consumed. Ans. Intoxicating substances should not be consumed:
1. Harm to physical health: Intoxicating substances can damage various organs of the body, including the brain, liver, and heart. They can also lead to addiction, which can have serious consequences for an individual’s health and well-being.
2. Impaired decision-making: Under the influence of intoxicating substances, people’s judgment and decision-making abilities are impaired. This can lead to risky behaviors, such as driving under the influence, which can have devastating consequences for oneself and others.
3. Mental health problems: Intoxicating substances can worsen existing mental health conditions, such as anxiety and depression. They can also contribute to the development of new mental health problems, such as psychosis.
4. Social and economic problems: Intoxicating substance use can lead to problems in relationships, employment, and finances. It can also contribute to crime and social unrest.
5. Overall well-being: Intoxicating substance use can have a negative impact on overall well-being, both physically and mentally. It can prevent people from reaching their full potential and living fulfilling lives.
4. Your muscles should be strong and efficient.
Ans. Strong and efficient muscles are important for daily activities and overall health because they enable us to perform tasks with ease, reduce the risk of injury, and improve our overall quality of life. When our muscles are strong and efficient, we can move freely and confidently, participate in physical activities without straining, and maintain good posture. Additionally, strong muscles can help support our joints and bones, reducing the risk of injuries and chronic conditions like arthritis. By taking care of our muscles through regular exercise and proper nutrition, we can maintain optimal muscle function and enjoy a better quality of life.
5. Answer the following.
a. How many types of muscles are there? Which are those types? Ans. There are three main types of muscles in the human body:
Skeletal muscle: Skeletal muscles are attached to bones and are responsible for movement. They are voluntary muscles, meaning that we can consciously control their contraction and relaxation. There are over 600 skeletal muscles in the body.
Smooth muscle: Smooth muscle is found in the walls of organs, such as the stomach, intestines, and blood vessels. It is involuntary muscle, meaning that we cannot consciously control its contraction and relaxation. Smooth muscle is responsible for functions such as digestion, blood vessel constriction and dilation, and bladder control.
Cardiac muscle: Cardiac muscle is found only in the heart. It is involuntary muscle and is responsible for pumping blood throughout the body. Cardiac muscle is striated, meaning that it has a striped appearance under a microscope.
b. What causes the problem of acidity? What is its effect on the body? Ans. Acidity is caused by an imbalance between the production and elimination of acids in the body. When the body produces more acids than it can eliminate, the excess acids accumulate in the bloodstream, causing a decrease in the body's pH levels.
There are several factors that can contribute to acidity in the body, including:
1. Poor diet: Consuming a diet high in processed foods, sugar, and refined carbohydrates can lead to an increase in acid production in the body.
2. Stress: Stress can cause the release of stress hormones, such as cortisol and adrenaline, which can disrupt the body's pH balance.
3. Lack of sleep: Poor sleep patterns can disrupt the body's natural detoxification processes, leading to an accumulation of acids in the body.
4. Environmental toxins: Exposure to environmental toxins, such as pollution and chemicals in personal care products, can contribute to acidity in the body.
5. Medical conditions: Certain medical conditions, such as kidney disease, can affect the body's ability to regulate pH levels, leading to acidity.
The effects of acidity on the body can be significant and widespread. Some common symptoms of acidity include:
1. Fatigue and weakness
2. Joint pain and inflammation
3. Digestive problems, such as bloating, gas, and constipation
4. Skin problems, such as acne and eczema
5. Respiratory issues, such as asthma and bronchitis
6. Heartburn and indigestion
7. Mood disturbances, such as anxiety and depression
8. Osteoporosis and bone loss
9. Immune system suppression
10. Increased risk of cancer
In severe cases, acidity can lead to more serious health problems, such as kidney stones, osteoporosis, and even organ failure. It is important to address acidity promptly and take steps to restore the body's pH balance to maintain optimal health.
c. Name the different types of teeth. What is the function of each type? Ans. Humans have four different types of teeth, each with a specific function:
• Incisors: The incisors are the four sharp, chisel-shaped teeth at the front of the mouth. They are used for biting and cutting food into smaller pieces.
• Canines: The canines are the pointed, fang-like teeth located next to the incisors. They are used for tearing and ripping food.
• Premolars: The premolars are the four teeth located between the canines and molars. They have two cusps, or raised points, and are used for tearing, crushing, and grinding food.
• Molars: The molars are the largest and strongest teeth located at the back of the mouth. They have multiple cusps and are used for chewing and grinding food.
6. Sketch and label a diagram of the digestive system and describe it in your own words.
Ans.
Mouth: The digestive journey begins in the mouth, where teeth break down food into smaller pieces. Saliva, produced by salivary glands, mixes with the food to moisten and lubricate it, making it easier to swallow.
Pharynx: The esophagus is a muscular tube that connects the mouth to the stomach. It uses rhythmic contractions called peristalsis to transport the food bolus, the mass of swallowed food, down to the stomach.
Stomach: The stomach is a J-shaped muscular sac that acts as a food reservoir. It mixes the food bolus with gastric juices, which contain hydrochloric acid and enzymes, to further break down the food and initiate protein digestion.
Small Intestine: The small intestine is the longest part of the digestive system, divided into three sections: the duodenum, jejunum, and ileum. Here, most of the digestion and absorption of nutrients occurs. The walls of the small intestine are lined with finger-like projections called villi, which increase the surface area for nutrient absorption.
Pancreas and Liver: The pancreas and liver play crucial roles in aiding digestion. The pancreas releases enzymes that break down carbohydrates, proteins, and fats. The liver produces bile, which helps emulsify fats, making them easier to digest.
Large Intestine: The large intestine, also known as the colon, absorbs water from the remaining food material and forms stool. It also houses beneficial bacteria that help with digestion and produce vitamins.
Rectum and Anus: The rectum is the final portion of the large intestine, where stool is stored until it is expelled through the anus during defecation.
This simplified sketch provides a basic understanding of the digestive system’s structure and function.
E X T R A
1. Choose and write the correct word.
1. The structure that connects bones to the muscles is the tendon.
(a) ligament
(b) tendon
(c) fascicle
(d) skin
2. Heat production is not performed by muscles.
(a) Motion
(b) Excretion
(c) Maintenance of posture
(d) Heat production
3. Approximately 600 skeletal muscles are there in the human body.
(a) 1000
(b) 600
(c) 100
(d) 60
4. Most of the fat digestion occurs in small intestine.
(a) rectum
(b) stomach
(c) small intestine
(d) large intestine
5. Protein digestion is accomplished in ileum.
(a) stomach
(b) ileum
(c) rectum
(d) duodenum
6. The main function of the muscular system is movement.
(a) excretion
(b) digestion
(c)movement
(d) contraction
7. The largest muscle of our body is in the thigh.
(a) arm
(b) face
(c) thigh
(d) None
Ans. (c)
2. Name the following:
1. Saliva is mixed with food in the mouth. Ans. True.
2. Gastric juice makes food alkaline. Ans. False. Gastric juice makes food acidic.
3. Pancreas is the largest gland in the body. Ans. False. Liver is the largest gland in the body.
4. Food becomes acidic in stomach. Ans. True
5. Cardiac muscles are said to be voluntary muscles. Ans. False. Cardiac muscles are involuntary.
6. Muscles contribute 60% of the weight of a healthy adult human body. Ans. False. Muscles contribute almost 40% of the weight of a healthy adult human body.
7. There are about 30 muscles in the human face. Ans. True
8. Muscles in our arms and legs have involuntary muscles. Ans. False. Muscles in our arm and legs are voluntary muscles.
9. Functions of organs like stomach, intestine, heart is carried out by voluntary muscles. Ans. False. Functions of these organs are carried out by involuntary muscles.
10. Smooth muscles are involuntary muscles. Ans. True.
11. The digestive function of the liver is to produce bile. Ans. True.
12. The muscular tissue has the ability to contract or shorten. Ans. True.
3. State whether the following statements are True or False. Correct and rewrite the false statement:
1. Cells can be easily seen with naked eyes. Ans. False. We can’t see cells with naked eyes, can be seen under microscope.
2. A single cell can perform all the functions in a unicellular organism. Ans. True.
3. Cell wall is present in both plant cells and animal cells. Ans. False. Cell wall is present only in plant cells.
4. Vacuoles are not found in plant cell. Ans. False. Large vacuole is found in plant cell.
5. Tissue is a group of dissimilar cells. Ans. False. Tissue is a group of similar cells.
6. Unicellular organisms have one celled body. Ans. True.
7. The basic living unit of an organism is an organ. Ans. False. The basic living unit of an organism is the cell.
8. The unit of measurement used for expressing dimension size of the cell is centimetre. Ans. False. The unit of measurement used for expressing dimension size of the cell is nanometer.
9. Micro-organism cannot grow in extreme adverse conditions. Ans. False. Some micro-organisms can survive in extreme adverse conditions e. g. ocean floor, ice polar region, hot water spring.
10. Some micro-organisms can grow without oxygen. Ans. True.
11. Amoeba has irregular shape. Ans. True.
12. The process of fermentation is used for making yogurt from milk. Ans. True.
13. Micro-organisms need an optimum temperature of 55°C to 70°C to grow. Ans. False. They need temperatures between 15°C to 35°C to grow well.
14. Cells with membrane bound organelles inside them are called prokaryotic cells. Ans. False. Cells with membrane bound organelles inside them are called eukaryotic cells.
15. Golgi bodies are the power houses of the cells. Ans. False. Mitochondria are the power houses of the cell.
Stomach, esophagus, liver, small intestine, rectum Ans. Liver which is a gland and others are parts of digestive tract.
2. Saliva, bile, pancreatic juice, gastric juice chyme Ans. Chyme, it is liquid food others are digestive juices.
5. Name the following:
1. Gastric juices in stomach Ans. Hydrochloric acid, Pepsin, Mucus.
2. Juices secreted by liver Ans. Bile.
3. Pancreatic juices. Ans. Trypsin, Lipase, Amylase.
4.Salivary gland secretion. Ans. Saliva.
5. Enzyme present in saliva. Ans. Ptyalin or Amylase.
6. Types of muscles. Ans. Skeletal, Cardiac and Smooth muscles.
7. Study of muscles.
Ans. Myology
6. Give scientific reason:
1. Skeletal muscles give shape to our body. Ans. Skeletal muscles, also known as striated muscles, are responsible for maintaining posture and giving shape to the human body. They do this by contracting and relaxing to move the bones and joints of the skeleton. When a muscle contracts, it shortens and pulls on the bone it is attached to, causing movement or maintaining position. This allows us to perform various physical activities such as walking, running, lifting, and standing upright. Additionally, skeletal muscles help regulate body temperature, support vital functions like breathing and digestion, and play a role in maintaining balance and coordination.
2. The process of digestion begins in the mouth. Ans. The process of digestion begins in the mouth because the teeth and salivary glands work together to break down food into smaller particles that can be easily swallowed and further broken down in the stomach. Saliva contains enzymes that start to break down carbohydrates in the food we eat, making it easier for the stomach acid and other digestive enzymes to continue the digestion process. Therefore, the mouth plays an important role in initiating the digestion process and preparing food for the rest of the digestive system.
3. Metabolic processes are impossible without enzymes. Ans. Enzymes are biological molecules that catalyze chemical reactions in the body, increasing their rates and efficiency. They are essential for metabolic processes, such as breaking down nutrients into energy, building and repairing tissues, and detoxifying harmful substances. Without enzymes, these processes would occur too slowly or not at all, leading to impaired cellular function and ultimately, death. Enzymes lower the activation energy required for reactions to occur, allowing them to proceed rapidly and efficiently, and thus, they are crucial for sustaining life.
7. Write short notes on:
1. Voluntary muscles Ans. Voluntary muscles, also known as skeletal muscles, are muscles that are under conscious control and can be voluntarily contracted and relaxed. These muscles are attached to bones and help move the body's skeleton. They are responsible for maintaining posture, regulating body movements, and facilitating locomotion. Voluntary muscles are innervated by somatic nerves, which carry signals from the brain to the muscles, allowing for deliberate movements. Examples of voluntary muscles include those in the arms, legs, and face.
2. Involuntary muscles Ans. Involuntary muscles, also known as smooth muscles, are muscles that are not under conscious control and operate automatically without any intentional effort. These muscles are found in the walls of hollow organs, such as the digestive tract, blood vessels, and airways. They are responsible for involuntary actions, such as peristalsis (the wave-like movement of food through the digestive tract), heart rate, and bronchial constriction. Involuntary muscles are controlled by the autonomic nervous system, which regulates their contraction and relaxation without conscious thought. Unlike voluntary muscles, involuntary muscles cannot be directly controlled by the brain, and their movements are reflexive and automatic.
3. Muscle and its types Ans. Muscles are contractile tissues responsible for movement and maintaining the structure of the body. There are three main types of muscles in the human body:
1. Skeletal Muscles (Voluntary Muscles): These are attached to bones by tendons and are under conscious control. Skeletal muscles enable voluntary movements such as walking, talking, and reaching. They work in pairs, with one muscle contracting while the other relaxes to produce movement.
2. Smooth Muscles (Involuntary or Visceral Muscles): Found in the walls of internal organs, blood vessels, and various structures, smooth muscles function involuntarily. They are controlled by the autonomic nervous system and play a vital role in processes such as digestion, blood vessel constriction, and respiratory functions.
3. Cardiac Muscle: Exclusive to the heart, cardiac muscle is also involuntary. It possesses a unique ability to contract rhythmically without fatigue. The coordination of cardiac muscle contractions ensures the pumping of blood throughout the body.
Each type of muscle serves specific functions, contributing to the overall movement, stability, and functionality of the human body. The interplay of these muscles allows for complex and coordinated actions, both voluntary and involuntary, essential for maintaining life and health.
4. Digestive glands Ans. Digestive glands are glands located in the digestive system that produce digestive juices and enzymes to help break down food into nutrients. These glands include:
• Salivary glands: Produce saliva that contains amylase, an enzyme that breaks down carbohydrates, and maltase, an enzyme that breaks down maltose.
• Gastric glands: Produce gastric juice that contains pepsinogen, an enzyme that breaks down proteins, and hydrochloric acid, which helps to denature proteins and kill bacteria.
• Pancreas: Produces pancreatic juice that contains a variety of enzymes, including amylase, lipase, and trypsin, which break down carbohydrates, fats, and proteins, respectively.
• Small intestine glands: Produce intestinal juice that contains enzymes such as lactase, sucrase, and maltase, which break down disaccharides into simple sugars.
• Liver: Produces bile, which is stored in the gallbladder and released into the small intestine to aid in fat digestion. Bile contains bile salts, which emulsify fats and increase their surface area for digestion.
These digestive glands work together to ensure that food is properly broken down into nutrients that can be absorbed and utilized by the body for energy, growth, and repair.
5. Enzymes Ans. Enzymes are proteins that boost chemical reactions in the body, making tasks like digestion, metabolism, and energy production more efficient. Different enzymes exist, such as digestive, metabolic, proteolytic, lipid-digesting, and carbohydrate-digesting enzymes. They help break down food, build macromolecules, detoxify, and more. Enzymes are vital for good health, and deficiencies or excesses can cause problems. Understanding enzymes helps develop treatments for medical conditions.
8. Differentiate between:
1. Voluntary and Involuntary muscles. Ans.
| Voluntary muscle | Involuntary muscle |
1. | Voluntary muscle means you can control it consciously. | Involuntary muscles are controlled by your subconscious. You have no control over them. |
2. | Skeletal muscles are voluntary muscles. | Cardiac muscles and smooth muscles are involuntary muscles. |
3. | Muscles in our arms and legs are voluntary muscles. | Muscles in heart, stomach, blood vessel, intestine are involuntary muscles. |
2. Skeletal muscle and Cardiac muscle. Ans.
| Skeletal muscle | Cardiac muscle |
1. | Skeletal muscles are voluntary muscles. | Cardiac muscles are involuntary muscles. |
2. | Muscles in our arms and legs are voluntary muscles. | Muscles in heart, stomach, blood vessel, intestine are involuntary muscles. |
3. | They hold bones of the skeleton together and gives shapes to our body. | They bring about contraction and relaxation of heart. |
9. Answer the following:
1. What is meant by organ system? Ans. An organ system is a group of organs that work together to perform specific functions and contribute to the overall functioning of the body. Examples include the digestive system, circulatory system, and respiratory system. These systems coordinate their activities to maintain homeostasis and support the various physiological processes necessary for life.
2. How are the bones in our body joined to each other? Ans. Bones in our body are joined to each other by joints. Joints allow for movement and provide structural support. They can be classified into different types, including hinge joints (e.g., elbows, knees), ball-and-socket joints (e.g., hips, shoulders), and pivot joints (e.g., neck). The connection between bones at joints is facilitated by ligaments, tendons, and cartilage.
3. What is the mutual relationship between muscles and bones? Ans. The mutual relationship between muscles and bones is essential for movement and structural support. Muscles, attached to bones by tendons, contract and exert force, causing movement at joints. Bones provide a framework and support for muscles to generate movement. This dynamic interaction between muscles and bones is crucial for activities like walking, lifting, and maintaining posture. Additionally, the stress placed on bones during muscle contractions helps maintain bone density and strength.
4. Are the muscles of the different organs in our body identical? Ans. No, the muscles of different organs in the human body are not identical. Each organ has its own unique type of muscle tissue that is specialized for the specific function of that organ. For example, the heart has cardiac muscle tissue that is designed for continuous contraction and relaxation to pump blood throughout the body, while the skeletal muscles in the arms and legs are designed for movement and support. Similarly, the smooth muscles in the digestive system are specialized for peristalsis, the rhythmic contraction and relaxation of muscles that helps move food through the digestive tract.
5. How do muscles perform their functions? Ans. Muscles perform their functions by contracting and relaxing. When a muscle contracts, it shortens and becomes thicker, producing force to move a bone or perform a task. When a muscle relaxes, it lengthens and becomes thinner, allowing the bone or body part to return to its resting position. Muscles work in pairs, with one muscle contracting while the opposite muscle relaxes, to create movement and maintain balance.
6. Which parts of our body are made up only of muscles? Ans. Several parts of our body are predominantly composed of muscles. These include:
1. Tongue: The tongue is a muscular organ responsible for various functions, including speech and swallowing.
2. Heart: The heart is a muscular organ that consists mainly of cardiac muscle tissue. It contracts rhythmically to pump blood throughout the body.
3. Sphincters: Muscular sphincters, such as the lower esophageal sphincter and anal sphincters, regulate the passage of substances between different organs.
While these organs have other components (such as connective tissue, blood vessels, and nerves), muscles play a predominant role in their structure and function.
7. What would happen if the cardiac muscles do not move? Ans. The contraction of cardiac muscles is vital for maintaining blood circulation, supplying oxygen and nutrients to the body’s tissues. The absence of these contractions, as in the case of cardiac muscle failure, would have severe and potentially fatal consequences. Immediate medical intervention, such as cardiopulmonary resuscitation (CPR) and advanced life support, is necessary to address cardiac arrest and restore heart function.
8. Food enters the stomach and the stomach muscles do not move. Ans. If the stomach muscles do not move, the food would not be able to be churned and broken down into smaller pieces. This would make it difficult for the body to absorb the nutrients from the food. The food would also stay in the stomach for a longer period of time, which could lead to nausea, vomiting, and constipation.
9. During digestion does all the food that we have eaten get converted into useful nutritive substances? Ans. No, not all the food we eat gets converted into useful nutrients during digestion. Some nutrients, like fiber, pass through the digestive system undigested. Other nutrients, like protein and carbohydrates, can be partially broken down but not fully absorbed. The efficiency of digestion varies depending on factors like the type of food, cooking methods, and individual differences in gut health and enzyme production.
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