You Must Know
1. Human and animal bodies are made up of many organ systems which carry out different functions.
2. Our digestive system helps in digesting and absorbing food.
3. The digestive system consists of the mouth, food pipe, stomach, small and large intestines and the anus.
4. All of us have two sets of teeth (milk teeth and permanent teeth) in our lifetime.
5. Our respiratory system helps in breathing in air, and exhaling out carbon dioxide.
6. The respiratory system consists of the nasal cavity, pharynx, wind pipe and the lungs.
7. The process of respiration helps in releasing energy, obtained from the breakdown of food.
8. The circulatory system consists of heart, blood vessels and blood.
9. Our heart supplies blood to all the organs of the body.
10. Blood transports food, oxygen, carbon dioxide and waste products to the relevant organs.
11. The nervous system controls and coordinates all the activities of our body. 12. Brain, spinal cord, nerves and sense organs comprise the nervous system.
13. The excretory system eliminates the waste products from the body.
14. Kidneys help us in excreting harmful waste products, and excess water, from our body.
Something To Know
A. Fill in the blanks.
1. The process, of breaking down of food, into fine and soluble particles, is called digestion.
2. Blood vessels, that carry blood from organs to heart, are called veins.
3. The nervous system consists of billions of neurons.
4. The right portion of the brain controls the left part of the body.
5. Kidneys are bean shaped organs that help in filtering out waste products.
6. The skin removes water, and excessive salts, in the form of sweat.
7. The male reproductive organ system has a pair of testis.
B. Write True or False for the following statements.
1. Large intestine is responsible for the digestion and absorption. of food. False
2. Pharynx is also called as the ‘voice box. False
3. Blood helps in maintaining our body temperature at a constant value. True
4. The blood vessels, which take blood away from the heart, to various parts of the body, are called arteries. True
5. Kidneys filter out waste products from the blood. True
C. Tick (✔) the correct option.
1. Bile is secreted by the-
salivary glands
liver (✔)
pancreas
kidneys
Answer – liver(✔)
2. The food, taken in by the humans, stays for about 2 to 3 hours, in the-
stomach (✔)
food pipe
small intestine
large intestine.
Answer – stomach(✔)
3. The tube-like structure, attached to the brain is/are known as-
veins
food pipe
nerves
spinal cord (✔)
Answer – spinal cord(✔)
4. The organ, in the human body, which filters out waste products, such as urea, from the blood, is the-
kidneys (✔)
lungs
urinary bladder
heart
Answer – kidneys(✔)
5. Ovaries are a part of the-
reproductive system (✔)
digestive system.
nervous system
excretory system
Answer – reproductive system(✔)
D. Answer the following questions in brief.
1. How many teeth are present in a four-month old child’s mouth?
Answer – Zero
2. Where is saliva produced?
Answer – Saliva is produced in mouth by salivary glands.
3. Define respiration.
Answer – The process of utilizing food to release energy is called respiration.
4. Name the flap that shuts off the wind pipe when you swallow food.
Answer – Epiglottis.
5. How many types of vessels are found in the circulatory system of human beings?
Answer – There are main two types of blood vessels in the human circulatory system. Viz arteries and veins which branch out into blood capillaries.
6. List down the main organs of the nervous system.
Answer – Brain, Spinal cord and Peripheral nerves.
7. Name the structure that protects the spinal cord.
Answer – Vertebral column.
8. Name the process of fusion of an egg with a sperm.
Answer – Fertilisation.
E. Answer the following questions.
1. What is digestion? Starting from the mouth, state the various steps involved in digestion.
Answer – The process of breaking the food into simple and soluble particles is called digestion.
Digestion in mouth: Food is chewed and changed into smaller particles. Saliva mixes with food to make it slippery. Some digestion happens in the mouth.
Digestion in stomach: Gastric juices are secreted in the stomach and some part of digestion takes place.
2. Draw a diagram of the tongue and show the location of the taste buds on it.
Answer –
3. Explain the role of diaphragm in the process of breathing.
Answer – Diaphragm facilitates expansion and contraction of lungs. When lungs expand, air enters the lungs and when the lungs contract, air goes out of the lung.
4. Give the function of the heart, and the blood vessels, in the circulatory system.
Answer – The function of the heart and the blood vessels, in the circulatory system:
Function of heart: Pumps blood to different parts of body.
Function of artery: Carries blood from heart to different organs.
Function of vein: Carries blood from different organs to the heart.
5. State the function of the nervous system. Briefly explain the role of nerves in it.
Answer – The nervous system is responsible for controlling all the functions in the body. The nerves work like channels through which the nerve impulses are transmitted.
6. Give a brief outline of the process of excretion, by the kidneys, in human beings.
Answer – Blood enters the kidney. Waste substances are filtered out from the blood, along with excess water. Waste and excess water convert into urine. Urine passes through ureters and gets collected in urinary bladder. Urine is expelled through urethra from time to time.
Value Based Question
Sahardiya’s family was having their dinner on the Daughter’s day. Her mother told them that their organisation has decided to contribute to the education of the children in a neighbourhood village. She went on to say that their organisation is trying to do something similar to what the blood, circulating in the human body, does.
1. State the values displayed by the organisation in which Sahardiya’s mother works.
Answer – Care for the girl child, care for children’s education.
2. State any two of the functions that the blood, circulating in the human body, does.
Answer – Two functions of blood are as follows:
Carrying food and oxygen to every part of the body.
Maintaining the temperature of the body.
3. Have a discussion in the class in which the students give their opinion, about why they (a) agree (b) disagree, with the ‘comparison’ made by Sahardiya’s mother.
Answer – Students, do it yourself.
Something To Do
1. Visit your local doctor. Request him to show you an instrument called the stethoscope. It is used to hear the heart beat of a person by keeping it on the chest at an appropriate place. Learn how to use it correctly and try to listen to the heart beat of your family members.
Answer – Students, do it yourself.
2. Now that you know how a stethoscope looks like, try to make one on your own. Take a long (approximately 50 cm) rubber tube and a funnel nearly 6-7 cm in diameter. Fit the rubber tube tightly at the end of the stem of the funnel. Place the open end of the tube in one of your ears and the open end of the funnel on the chest of a person. The sounds, you hear, are due to the ‘heart beats’ of that person. Use your self-made stethoscope to listen to the heart beat of your friends and family members.
Answer – Students, do it yourself.