Blood and its Functions
Meaning of Blood:
Blood is a liquid connective tissue, consists of Plasma (Fluid part) and Cell (Solid part).
Functions of Blood:
- Blood carry Oxygen and essential nourishment through arteries to every living tissue in the body.
- Carbon Dioxide and waste products such as urea are removed by the Blood through Veins.
- It controls body temperature
- Blood defends against infections
- Blood is act as a transported of all gases and supply to different part of body.
- It is also called as the Defence mechanism.It fight against Bacteria & prevent entry of organism
The quantity of Blood:
A healthy man has about 5 Litre of Blood in the body, while a women has about 500ml. less than man.
Constituents of Blood:
There are two main constituents of Blood as Solid or Cellular part"Blood Cell"(consisting of 35%) & Fluid or humoral part called "Plasma"(65%).
Types of Blood Cell:
- RBC (Red Blood Corpuscles)
- WBC (White Blood Corpuscles)
The RBC, which are called Erythrocytes are disc shaped cells. It is visible under a microscope. They have no nucleus. It contain a pigment called Haemoglobin which gives Blood its red color. Haemoglobin is composed of an Iron containing pigment called haema and a protein called globin. In a normal human being the amount of haemoglobin is about 14-15.6 cubic whereas in a woman it is about 11-14 grams. RBCs are produced in the spleen and the bone-marrow at the rate of 1.2 million corpuscles per second. In a life time the Bone marrow creates about half a tone of RBC.
RBC formation of a baby started from the 3rd week of intra-uterin life.
Functions of RBC:
- Haemoglobin in the RBC picks up Oxygen in the lung tissue by forming a chemical compound with it
- Oxygen reactions with the products of digestion in order to produce energy
- Carbon dioxide produced in these reactions and returns to the lungs via the heart where cycle starts again
Value of RBC:
6000 to 11,000
- The WBC are the White blood corpuscles are the soldier of the body's defend system. They are a little larger than RBC.
Functions of WBC:
Neutrophils are attack the invading bacteria. Lymphocytes are second, they produce anti-bodies. Antibodies protect the body against antigen, foreign substance like Bacteria, viruses, toxins etc.
Value of WBC:
3 million to 5 million
This is a substance which sets off blood clotting, a mechanism that seals tears in Blood Vessels. Blood Platelets live only for a few hours.
Value of Platelets:
450,000 to 1150,000