Question 1 What is a blood?
Question 2 Name the components of blood?
Question 3 What is the function of RBC?
Question 4 What is the function of WBC?
Question 5 What is the function of platelets?
Question 6 What is the function of arteries?
Question 7 What is the function of veins?
Question 8 What is the function of capillaries?
Blood is a red coloured liquid which circulate in our body and contain haemoglobin. It is a connective tissue.
The components of blood are Plasma, RBC, WBC, platelets.
Plasma : It is the liquid part of blood,colourless,90% water, dissolve substances such as proteins, digested food, salts, waste products, all the cells are present in it.
RBC : It is red in colour due to haemoglobin which carries oxygen from lungs to all cells of body and carbon dioxide from body tissues to lungs.
They are formed in bone marrow, have short life span and does not contain nuclei.
WBC : It helps to fight infection and protect us from diseases. WBC produce chemicals called antibodies to fight infection. They are spherical or irregular in shape. They have nucleus and are smaller in number than RBC.
Platelets : They are formed in bone marrow. They do not have nuclei, help in clotting of blood.
Functions of Blood
(1) It transports oxygen, carbon dioxide, nutrients, hormones ions, enzymes, waste products from one part to other.
(2) They help in protection against diseases.
(3) Helps to regulate body temperature.
Human Circulatory System
It consist of Arteries, veins, capillaries, blood and heart.
They are thick walled, elastic blood vessels, carry blood from heart to other parts.
They are thin walled blood vessels, carry blood from various parts of body to heart, have valves which prevent the back flow of blood.
(1) They are thin walled, extremely narrow, occurs at the terminal of artery and vein, they join arteries and veins together.
(2) Walls are permeable to water and dissolved substances so that exchange of material between blood and cell body take place.