Lakhmir Singh & Manjit Kaur Solutions: Life Processes - 4 | Science Class 10 PDF Download

Page No - 74

Question 39:
(a) How many types of blood vessels are there in the human body ? Name them.
(b) Why does the heart need valves ?
Solution :
(a) There are three types of blood vessels – arteries, veins and capillaries.(b) Heart needs valves to prevent the backflow of blood so that the blood flows only in one direction.

Question 40:
A dialysis machine contains long tubes coiled in a tank containing dialysing solution :
(i) Of what substance are the tubes made ?
(ii) What does the dialysing solution contain ?
(iii) Name the main waste which passes into the dialysing solution.
Solution :
(i) Cellulose.
(ii) Water, glucose, salts in similar concentration to those in normal blood.
(iii) Urea.

Question 41:
State the differences between artery, vein and capillary.
Solution :

Question 42:
(a) What are the upper parts of the heart called ?
(b) What are the lower parts of the heart called ?
(c) What is the name of blood vessels which connect arteries to veins ?
(d)
(i) Which side of the heart pumps blood into the lungs ? .
(ii) Which side of the heart pumps blood into entire body (except the lungs) ?
Solution :
(a) Atria
(b) Ventricles
(c) Capillaries
(d)
(i) Right side
(ii) Left side

Question 43:
(a) What are the methods used by plants to get rid of their waste products ?
(b) How are waste products excreted in Amoeba ?
Solution :
(a) Thevarious methods used by the plants to get rid of their waste products are
(i) the plants get rid of gaseous waste products through stomata in leaves and lenticels in stems.
(ii) They get rid of solid and liquid waste by shedding off leaves, peeling of bark and falling of fruits.
(iii) Secreting gums and resins.
(iv) Plants excrete some waste substances into the soil around them.
(b) Excretion in amoeba: In amoeba, the waste material carbon dioxide is removed by diffusion through the cell membrane, but nitrogenous waste and excess water are removed by contractile vacuole.

Question 44:
(a) What is lymph ? State two major functions of lymph.
(b) What is meant by saying that the blood pressure of a person is 120/80 ?
Solution :
(a) Lymph is a light yellow liquid. It is a medium of circulation in human body which flows only in one direction – from body tissues to the heart. The functions of lymph are:
(i) It takes part in the nutritive process of the body.
(ii) It protects the body by killing the germs drained out of the body tissues with the help of lymphocytes contained in the lymph nodes, by making antibodies.
(iii) It helps in removing the waste products like fragments of dead cells etc.
(b) If the blood pressure of a person is 120/80 it means that the systolic pressure is 120 mm Hg and diastolic pressure is 80 mm Hg.

Question 45:
What is hypertension ? Why is it caused ? What harm can it do ?
Solution :
High blood pressure is called hypertension. It is caused by the constriction of very small arteries which results in increased resistance to blood flow. Very high blood pressure can lead to rupture of artery and internal bleeding.

Question 46:
What are the various components of blood ? State their functions.
Solution :
The main components of blood are:
(i) Plasma: It carries all the dissolved substances such as proteins, digested food, common salt etc from one part to another part of the body.
(ii) Red blood corpuscles (RBC): It carries oxygen from the lungs to all the cells of the body.
(iii) White blood corpuscles (WBC): It fights infection and protects us from diseases.
(iv) Platelets: It helps in the coagulation of blood in a cut or wound.

Question 47:
With which human organ systems (or human systems) are the following associated ?
(i) vena cava (ii) glomerulus (in’) alveoli (iv) villi
Solution :
(i) Circulatory system.
(ii) Excretory system.
(iii) Respiratory system.
(iv) Digestive system.

Question 48:
What is meant by ‘systolic pressure’ and ‘diastolic pressure’ ? What are their normal values ?
Solution :
The maximum pressure at which the blood leaves the heart through the main artery (Aorta) during contraction phase is called systolic pressure. The minimum pressure in the arteries during relaxation phase of the heart is called the diastolic pressure. The normal blood pressure values are: Systolic pressure: 120 mm Hg. Diastolic pressure: 80 mm Hg.

Question 49:
(a) What is meant by ‘heart beat’ ? What is the usual heart beat rate at rest ?
(b) What change occurs in heart beats if a person runs for a while ? Why ?
Solution :
(a) Heart beat: One complete contraction and relaxation of the heart is called a heart beat. The usual heart beat rate at rest is 72 times /minute.
(b) The heart beats faster when a person runs for a while because the body needs more energy under these conditions.

Question 50:
(a) What is blood ? Why is it red ?
State the functions of blood in our body.
Name a circulatory fluid in the human body other than blood.
Solution :
(a) Blood is a red coloured liquid which circulates in our body. It is red because it contains a pigment called haemoglobin in its red cells.
(b) Functions of blood:
(i) It carries oxygen from the lungs to different parts of the body.
(ii) It carries carbon dioxide from the body cells to the lungs for breathing out.
(iii) It carries digested food from the small intestine to all the parts of the body.
(iv) It carries waste product called urea from the liver to the kidneys for excretion in the form of urine.
(v) It protects the body from diseases.(c) Lymph.

Question 51:
(a) What is meant by human circulatory system ? Name the organs of the circulatory system in humans.
Draw a diagram of the human heart and label its parts.
What is meant by the terms ‘single circulation’ and ‘double circulation’ ?
Solution :
(a) Human circulatory system is a system which is responsible for the transport of materials inside the body. The various organs of the circulatory system in humans are: heart, arteries, veins and capillaries.
(b)

(c) Single circulation is a type of circulatory system in which the blood passes through the heart only once in one complete cycle of the body.Double circulation is a circulatory system in which the blood travels twice through the heart in one complete cycle of the body.

Question 52:
Describe the working of human blood circulatory system with the help of a suitable diagram which shows all the steps involved.
Solution :
Working of Human blood circulatory system takes place in the steps below:
(i) When the muscles of all the four chambers are relaxed, the pulmonary vein brings the oxygenated blood from the lungs in the left atrium of the heart.
(ii) When the left atrium contracts, the oxygenated blood is pushed into the left ventricle through valve V1.
(iii) When the left ventricle contracts, the oxygenated blood enters the main artery called aorta from which it goes to the different body organs through small branches called arterioles and capillaries. (iv) The main artery carries the blood to all the organs of the body head, arms etc except the lungs. The oxygenated blood gives off oxygen, digested food and dissolved materials to the body cells. The carbon dioxide produced in the cells enters the blood. The deoxygenated blood enters main vein called vena cava which carried it to the right atrium of the heart.
(v) When the right atrium contracts, the deoxygenated blood enters right ventricle through valve V2.
(vi) When the right ventricle contracts, the deoxygenated blood enters the lungs through pulmonary artery and releases carbon dioxide and absorbs fresh oxygen from air. The blood becomes oxygenated again and is sent to the left atrium of heart by pulmonary vein for circulation in the body. This whole process is repeated continuously. 

Diagram to show blood circulation in human body

Question 53:
(a) Name the red pigment which carries oxygen in the blood.
(b) Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds ?
(c) How many chambers are there in the heart of : (i) an amphibian, (ii) a mammal, and (iii) a fish ?
(d) Describe the circulatory system in a fish.
Solution :
(a) Haemoglobin.
(b) It is necessary to separate the oxygenated blood from mixing with deoxygenated blood as mammals and birds have high energy needs because they constantly require energy to maintain their body temperature.
(c)
(i) Three chambered heart.
(ii) Four chambered heart.(iii) Two chambered heart.
(d) The fish has a two chambered heart. Oxygenation of the blood takes place in the gills. The oxygenated blood from the gills is supplied to the body parts of the fish where oxygen is utilized and carbon dioxide enters into it making it deoxygenated. The deoxygenated blood returns to the heart to be pumped into gills again.

Question 54:
(a) What is lymphatic system ? What are its functions ?
(b) What is blood pressure ? What are the two factors used to express the blood pressure of a person ?
(c) Name the main nitrogenous waste in the human blood. How is it removed from the blood ?
Solution :
(a) Lymphatic system: A system of tiny tubes called lymph vessels (lymphatics) and lymph nodes (lymph glands) in the human body which transports the liquid called lymph from the body tissues to the blood circulatory system is called lymphatic system. Functions of lymphatic system:
(i) It takes part in the nutritive process of the body.
(ii) It protects the body by killing the germs drained out of the body tissues with the help of lymphocytes contained in the lymph nodes, by making antibodies.
(iii) It helps in removing the waste products like fragments of dead cells etc.
(b) Blood pressure: The pressure at which the blood is pumped around the body by the heart is called blood pressure. The two factors which expresses the blood pressure a person are systolic pressure and diastolic pressure.
(c) Urea is the main nitrogenous waste in human blood. It is removed from the body in the form of urine through the kidneys.

Question 55:
(a) Name the various organs of the human excretory system.
(b) Draw a neat labelled diagram of the human excretory system.
(c) What is the function of excretory system in humans ?
Solution :
(a) The excretory system of human beings consists of the following main organs: two kidneys, two ureters, bladder and urethra.

The human excretory system ( or urinary system) 

(c) The excretory system removes the poisonous waste substances from the body in the form of urine and maintains ionic balance called osmoregulation.

Question 56:
(a) Describe the mechanism of urine formation in human excretory system. Draw a labelled diagram to illustrate your answer.
(b) Where is urine carried through ureters ?
(c) What is urethra ?
Solution :
(a) Urine formation: The dirty blood containing waste like urea enters the glomerulus which filters the blood. During filtration, the substance like glucose, amino acids, salts, water, urea etc present in the blood pass into Bowman’s capsule and then enter the tubule of nephron. When the filtrate containing useful substances as well as the waste substances passes through the tubule, the useful substances like glucose, amino acids, most salts and water are reabsorbed into the blood through blood capillaries surrounding the tubule. Only the waste substances like urea, some unwanted salts and excess water remains behind in the tubule. This yellowish liquid is called urine.

Diagram to show the working of human excretory system

(b) Urinary bladder.
(c) Urethra is a tube which passes out the urine from the body collected in the urinary bladder.

Question 57:
(a) What is meant by dialysis ? What type of patients are put on dialysis ?
(b) Explain the principle of dialysis with the help of a labelled diagram.
Solution :
(a) Dialysis: The procedure used for cleaning the blood of a person by separating the urea from it is called dialysis. The patients with kidney failure are put on dialysis. (b) Principle of Dialysis: The blood from an artery in the patients arm is made to flow into the dialyser of a dialysis machine made of long tubes of selective permeable membrane (like cellulose) which are coiled in a tank containing dialysing Solution. The dialysing Solution contains water, glucose and salts in similar concentrations to those in normal blood. As the patient’s blood passes through the dialysing Solution most of the waste like urea present in it pass through the selectively permeable cellulose tubes into the dialysing Solution. The clean blood is pumped back into a vein of the patients arm.

The principle of the kidney dialysis machine

Question 58:
(a) Why is transport of materials necessary in an organism (plant or animal) ?
(b) What is the need of special tissues or organs for transport of substances in plants and animals ?
(c) How are water and minerals transported in plants ?
(d) How is food transported in plants ?
Solution :
(a) Transport in organisms (plants and animals) is necessary as it absorbs all essential substances and transports them to all parts so that they reach each and every cell of the body.
(b) Special tissues and organs are needed for the transport of substances in plants and animals because these tissues and organs can pick up the essential substances like food, oxygen, water, etc at one end of their body and carry them to all other parts.
(c) Water and minerals are transported to various parts of the plant by xylem tissues called xylem vessels and tracheids. Plants take in water from the soil through the roots. The water containing minerals called cell sap is carried by the xylem vessels to all the parts of the body. The roots have root hairs to absorb water and minerals from the soil by diffusion and then pass from cell to cell by osmosis through epidermis, root cortex, endodermis and then reach the root xylem. The water enters the root xylem into the stem xylem and then reaches the leaves from the petioles.

Diagram to show how water  (and dissolved minerals ) are 

transported from the soil up to the leaf of a plant

(d) Transportation of food in plants: The transport of food from the leaves to other parts of the plant is called translocation. Phloem tissue transports the food from the leaves to the other parts of the plant. The movement of food in phloem takes place by utilising energy. The sugar made in the leaves is loaded into the sieve tubes of phloem by using ATP. Water enters the sieve tube containing sugar which causes high pressure and pushes the food to all the parts of the plant having low pressure. This is how the food is transported according to the needs of the plant.