Biology, asked by saurabhsunil950, 1 year ago

What are the compositions and functions of blood

Answers

Answered by Arsalan78666
8
Blood is a red coloured liquid which circulates in our body. It is red in colour because it contains a red pigment calledhaemoglobin in its red cells. Blood is a connective tissue,  consists of four things namely Plasma, Red blood corpuscles (Red blood cells or RBCs), White blood corpuscles (White blood cells or WBCs) and platelets.

Plasma is a liquid also known as Fluid matrix consist of three types of cells which keep floating in it i.e red blood cells, white blood cells and platelets.


Functions of Blood

Blood has three main functions in the human body i.e Transport of substances from one part of the body to the other like respiratory gases, waste products, enzymes etc, Protect against diseases and Regulation of body temperature.

Blood regulates body temperature.It carries oxygen from lungs to different parts of the body.It carries carbon dioxide from the body cells to the lungs for breathing out.It carries digested food from the small intestine to all parts of the body.It carries hormones from the endocrine glands to different organs of the body.It carries waste product urea from the liver to the kidneys for excretion.Defends against infection.

On an average, a healthy man has about 5 litres of blood in the body, while woman has about 500ml less than man. So, total blood is about 60-80 ml/kg of body weight.

Plasma

The fluid or liquid part of blood is calledplasma. It is a colourless liquid which contains 90% water, protein and inorganic salts. It also contains some organic substances in dissolved form like glucose, amino-acids, fats, urea, hormones; enzymes etc.It carries these dissolved substances from one part to another part in the body. The protein in plasma includes antibodies to assist in the body’s defence system against disease and infection.

Red Blood Corpuscles (RBC)

Also known as erythrocytes are disc- shaped cells concave in the middle and visible under a microscope. RBC carries oxygen from the lungs to all the cells of the body. They have no nucleus and contain a pigment called haemoglobin which is made up of an iron containing pigment known as haema and a protein called globin. RBCs are produced in the spleen and the bone marrow and live for about four months because they lack nucleus. So, when we donate blood to save the life of a person, then the loss of blood from our body is recovered within a day because red blood cells are made very fast in the bone marrow. Life of the RBC is about 100-120 days.

Functions

Haemoglobin in RBC picks up oxygen in the lung tissues by forming a chemical compound with it.This oxygen is carried to the tissues where it is used in the chemical reactions to produce energy.It then combines with carbon dioxide which is produced in these reactions and returns to the lungs with the heart where the cycle star lungs

White Blood Corpuscles (WBC)

WBC is also known as leukocytes. They fights with infection and protect us from diseases because they eat up the germs which causes diseases. That is why they are also known as ‘soldiers’ of the body’s defence system. They are round or irregular, semi- transparent cells containing a nucleus and visible under a microscope. They are little larger than RBC. Some White blood cells make chemicals called ‘antibodies’ to fight against infection i.e why they provide immunity in our body. WBC in the blood is much smaller in number then red blood cells.

Functions

Broadly, WBC acts as a defence system in the body.There are several varieties of WBC performing specific functions such as,Neutrophils (65 to 70% of the total WBC) attack the invading bacteria and engulf them. Lymphocytes (25% of WBC) produces antibodies which protect the body against antigen and thus provide immunity against infection. Basophilssecrete anticoagulant called heparin which prevents clot within the blood cells.Eosinophils and monocytes also assist in defence mechanism of the body by becoming active against specific antigens.

Blood platelets

Blood Platelets are also known asthrombocytes. They are tiny, circular or oval colourless cells formed in the bone marrow. They lack nucleus and help in the coagulation of blood (clotting of blood) in a cut or wound, due to which bleeding stops. All the blood cells are made in the bone marrow from the cells called stem cells. 

Blood clotting is a body’s defence system to combat bleeding. Plasma contains a soluble protein fibrinogen of the blood which produces the insoluble protein called fibrin essential for blood coagulation which is formed in the liver.

Process of clotting

 In an injury blood platelets break down and release an enzyme which helps in the formation of fibrin from fibrinogen. This fibrin forms clot in the form of mass of fibres which stops bleeding from blood vessels. After clotting, a straw- coloured fluid called serum is left.



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Answered by abhay1850
4
Composition of blood. Blood is classified as a connective tissue and consists of two main components: Plasma, which is a clear extracellular fluid. Formed elements, which are made up of the blood cells and platelets.

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