(a) How many types of blood vessels are there in the human body ? Name them.
(b) Why does the heart need valves ?
(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.
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.
(ii) Water, glucose, salts in similar concentration to those in normal blood.
State the differences between artery, vein and capillary.
(i) It is a thick walled blood vessel
It is a thin walled blood vessel
it is an extremely narrow blood vessel having very thin walls.
(ii) It carries blood from the heart to different parts of body
it brings blood from the different parts of the body to the heart.
they form an extensive network throughout all living cells in the body and connect arteries and veins
(iii) It can dilate or constrict depending on the regulatory requirements of the body
it cannot dilate or constrict
It can dilate or constrict according to the requirement of the tissue
(iv) It does not contain any valve
It contains simple valves which permit blood flow only towards the heart.
It does not contain any valves
(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 ?
(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) ?
(i) Right side
(ii) Left side
(a) What are the methods used by plants to get rid of their waste products ?
(b) How are waste products excreted in Amoeba ?
(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.
(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 ?
(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.
What is hypertension ? Why is it caused ? What harm can it do ?
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.
What are the various components of blood ? State their functions.
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.
With which human organ systems (or human systems) are the following associated ?
(i) vena cava (ii) glomerulus (in’) alveoli (iv) villi
(i) Circulatory system.
(ii) Excretory system.
(iii) Respiratory system.
(iv) Digestive system.
What is meant by ‘systolic pressure’ and ‘diastolic pressure’ ? What are their normal values ?
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.
(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 ?
(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.
(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.
(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.
(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’ ?
(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.
(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.