Q 1 – What is blood?
Ans. Blood is a fluid that is pumped through the body by the heart and contains plasma, blood cells and platelets.
Q 2 – What is plasma?
Ans. Plasma is a straw-coloured watery fluid of the blood and lymph that contains no cells, but in which the blood cells (erythrocytes, leukocytes and thrombocytes) are suspended.
Q 3 – Define the RBC (red blood cell).
Ans. Red blood cell is disc-shaped, biconcave cells with no nucleus. It contains haemoglobin to carry oxygen to different parts of the body.
Q 4 – What is platelet?
Ans. Platelet is an irregular, disc-shaped particle in the blood that assists in blood clotting.
Q 5 – What is the function of arteries?
Ans. Arteries carry oxygen-rich blood from the heart to all parts of the body.
Q 6 – What is the function of veins?
Ans. Veins carry carbon dioxide-rich blood from all parts of the body to the heart.
Q 7 – What is capillary?
Ans. Capillary is any of the thin-walled, minute blood vessel connecting arterioles with venules.
Q 8 – What is heart?
Ans. Heart is the hollow muscular organ located behind the sternum and between the lungs. Its rhythmic contractions and relaxation pumps blood throughout the body.
Q 9 – How many types of blood vessels are there? Name them.
Ans. There are three types of blood vessels:
- arteries
- veins
- capillaries
Q 10 – Name the four chambers of the heart.
Ans.
- right atrium
- left atrium
- right ventricle
- left ventricle
Q 11 – Where is the human heart located?
Ans. The heart is located in the chest cavity.
Q 12 – What is excretion?
Ans. The process of removal of wastes produced in the cells of the living organisms is known as excretion.
Q 13 – Write the names of two vascular tissues present in the plants.
Ans.
- Xylem
- Phloem
Q 14 – Define transpiration.
Ans. Transpiration is the process by which excess water in plants evaporates through the stomata of the leaves.
Q 15 – Write the composition of urine.
Ans. Urine consists of 95% water, 2.5% urea and 2.5% other wastes.
Q 16 – What is the use of a stethoscope? Explain its structure as well.
Ans. Stethoscope is used by doctors to amplify the sound of the heart. It consists of two earpieces, a chest piece and a tube that joins these parts. With the help of this device, doctors can check out a disease by listening carefully to the heartbeat.
Q 17 – What is blood? What does it consists of?
Ans. Blood is the fluid circulating through the heart, arteries, veins. It carries oxygen and nutrients to the cells of the body and removes waste materials and carbon dioxide from the body. Blood consists of the liquid, i.e., plasma, red blood cells (RBCs), white blood cells (WBCs) and platelets.
Q 18 – What are the functions of blood?
Ans. The functions of blood are:
- It transports oxygen to all parts of the body from the lungs.
- It transports the digested food to all parts of the body from the small intestine.
- It helps in removing waste products and carbon dioxide from the cells.
Q 19 – What do you mean by dialysis?
Ans. If the kidneys of a person fail to function due to infection or injury, blood is filtered periodically by using an artificial kidney to eliminate the wastes from the blood. This process is called dialysis.
Q 20 – What kind of blood flows in the arteries and veins?
Ans. Arteries carry oxygen-rich blood, whereas veins transport carbon dioxide-rich blood. Exceptionally, pulmonary artery carries carbon dioxide-rich blood (i.e., impure) and veins carry oxygen-rich blood (i.e., pure).
Q 21 – Explain the removal of urine from the body.
Ans. After filtration, the urine reaches the urinary bladder by passing through ureter; it gets stored in the bladder. Whenever required, it gets eliminated through an opening called urethra.
Q 22 – Write the importance of heartbeat.
Ans. The rhythmic contraction and relaxation constitute a heartbeat. Heartbeat helps in pumping the blood throughout the body.
Q 23 – How does the absorption of water and minerals take place in the plants?
Ans. With the help of roots, plants absorb water and minerals. Roots contain root hair which are fine threadlike structures made of a single cell. Water and minerals from the soil enter root hair, pass through the secondary root and reach the vascular tissue, xylem. From xylem it is transported to all parts of the plant.
Q 24 – Why the heart has different chambers?
Ans. Blood has to transport both oxygen and carbon dioxide. Hence the heart has different chambers to prevent mixing of oxygen-rich blood and carbon dioxide-rich blood with each other.
Q 23 – What is translocation. Where does it take place?
Ans. Translocation is the process of transport of soluble products of photosynthesis from leaves to other parts. It occurs in phloem.
Q 26 – Explain the formation of urine.
Ans. Blood contains nitrogenous wastes. These have to be removed from the body, since they are toxic and so are harmful for the body. The elimination is done by the kidneys.
Blood contains both useful and harmful substances. When it reaches the kidney, the filtration is done by its unit called nephron. The useful substances are absorbed back, whereas the harmful substances get eliminated as urine.
Q 27 – Where do plants store their waste products?
Ans.
- Plants store their waste products like gums and resins in the old xylem.
- Plants store wastes in vacuoles and leaves that fall off.
Q 28 – Write the structures and functions of blood vessels.
Ans. The structures and functions of blood vessels are given as follows:
Arteries:
- Structure: Arteries have thick elastic wall because they carry blood from the heart at a high pressure to other parts of the body.
- Function: They carry oxygen-rich blood from the heart to all parts of the body.
Veins:
- Structure: They have thin walls comparatively to arteries because the blood flows with less pressure. Rather they have valves which prevents back flow of blood.
- Function: They carry carbon dioxide-rich blood from all parts of the body to the heart.
Capillaries:
- Structure: These are very thin blood vessels, having walls one cell thick.
- Function: Across the thin wall of the capillaries, the exchange of gases and nutrients take place between the blood and the surrounding cells.’
Q 29 – Explain the working of heart.
Ans.
- Deoxygenated blood from all parts of the body enters the right chamber of the heart called right artium or auricle through superior and inferior vena cava.
- As the atrium contracts deoxygenated blood flows from right atrium to right ventricle through tricupsid valve.
- When ventricle is full tricupsid valve shuts to prevent backflow of blood into atrium.
- The ventricle then contracts blood into pulmonary artery to reach the lungs where it get oxygenated.
- Oxygenated blood then returns to the left atrium of heart through pulmonary veins.
- As the atrium contracts, oxygenated blood flows from left atrium to left ventricle through mirtal valve.
- And when ventricle contracts, blood leaves the heart through aortic valve to the arteries. Arteries circulate blood throughout the body.
Q 30 – What are the various components of blood. Write function of each component.
Ans. Blood has four main components, i.e., plasma, red blood cells, white blood cells and platelets. Function of various components are:
- Plasma: Plasma is the watery component of blood. It suspends other components of blood. It contain many important dissolved substances, such as protein, electrolytes, nutrients, gases and waste products. It maintain the exact pressure of the blood.
- Red blood cells: RBC contain haemoglobin protein, whose main function is to carry oxygen to all parts of the body and to bring carbon dioxide to the lungs.
- White blood cells: Main function of WBC is to fight against infections diseases and foreign invaders.
- Platelets: It helps in clotting of blood during injuries and thus, prevent excess loss of blood from our body.
Q 31 – Explain the excretion in birds, fishes, lizards, dogs and humans.
Ans. The way of the elimination of waste products from the body of animals depends on the availability of water. Animals like birds and lizards excrete a white coloured, semi-solid product, known as uric acid. Aquatic animals (like fish) excrete the waste materials (i.e., ammonia) in the gaseous form which directly dissolve with water. Dogs and human beings excretes urea.
Q 32 – Explain human circulatory system with a well labelled diagram.
Ans. Circulatory system is the life support system of our body that provides our body cells with nutrients and oxygen. It takes away waste product from the body cells. Our circulatory system comprises of the heart, blood, blood vessels and lungs.
- Blood is the fluid that carries oxygen and nutrients to various parts of the body and takes away wastes and carbon dioxide from the cell for elimination.
- Blood vessels comprises of arteries, veins and Capillaries. Arteries carry oxygen-rich blood from the heart to various parts of the body. Capillaries are single-walled vessels which exchange gases and nutrients from the cells.
- Veins carry carbon dioxide-rich blood from different parts of the body to the heart.
- Heart is a muscular organ with four chambers which pumps blood throughout the body. It pumps carbon dioxide-rich blood to the lungs for purification.
- When it receives oxygen-rich blood from the lungs it again pump this blood to arteries for transportation to various body parts.
- Lungs helps in exchange of gases between air we breathe in and the blood. It helps in elimination of carbon dioxide from blood and making it rich in oxygen content.
Q 33 – Which feature of heart does not allow mixing of oxygen-rich blood with carbon dioxide-rich blood?
Ans. Heart is divided into four chambers and are protected with valves which prevent their backflow. Thus, these features prevent mixing of oxygen-rich blood with carbon-dioxide rich blood.
Q 34 – Why do doctor often holds our wrist when we go for a check up?
Ans. Doctor holds our wrist to count our pulse rate and to check whether it is normal or not.
Q 35 – Why wall of right ventricle is thinner than that of the left ventricle?
Ans. This is because the left ventricle has to pump blood all the way around the body, but the right ventricle only has to pump it to the lungs.
Q 36 – What will happen if oxygenated and deoxygenated blood gets mixed?
Ans. Mixing of oxygenated blood with deoxygenated blood will lead to less oxygen supply to the cells. Under oxygen deficient condition, cells will not perform normally which may adversely affect the organism as a whole.
Q 37 – Does artery always carries oxygen-rich blood?
Ans. No. Pulmonary artery carries carbon dioxide-rich blood from heart to the lungs.
Q 38 – Sponges and Hydra do not posses any circulatory system. How nutrients and oxygen is transported inside their body?
Ans. The water in which sponges and Hydra live brings food and oxygen as it enters their bodies. The water also carries away waste material and carbon dioxide as it moves out. Thus, these animals do not need a circulatory system.
Q 39 – Water from soil moves inside the root cell but never comes out from root cell to soil. Why?
Ans. Water always move from a region of its higher concentration to a region of its lower concentration. This process is called osmosis. Concentration of water is more in the soil compared to its concentration inside the root cell, so it move from soil to the root cell and not from root cell to the soil.
Q 40 – How does applying pressure to a bleeding wound help?
Ans. By applying pressure to a bleeding wound, we constrict the blood vessels manually and prevents too much loss of blood from the wound.
Q 41 – When we get small bruises, bleeding stops automatically after some time. Why?
Ans. Bleeding stops automatically in small bruises after some time due to clotting of blood.
Q 42 – What would be the colour of wounded area? Why?
Ans. Colour of wounded area will be dark red due to formation of clot.
Q 43 – Which type of blood cells are responsible for clotting of blood?
Ans. Blood platelets.
Q 44 – What value of Sujata is shown here?
Ans. Sujata is intelligent, swift in her action, helpful, etc.
Q 45 – What is uremia?
Ans. Uremia is a disease which is caused due to raised level of urea in the blood.
Q 46 – What are the other health issues related with drinking less water?
Ans. Dehydration, stomachache, dry skin, headache, restlessness, etc.
Q 47 – What is the role of water in elimination of waste?
Ans. Water helps in elimination of nitrogenous waste and other salts through excretion and sweating.
Q 48 – What values of Natasha is shown here?
Ans. Natasha is obedient, sincere and mature enough to understand her teacher.