Unit :- Blood ( Part :- 2 )

 Cellular content of blood :- 

There are three types of blood cells — 

1. Erythrocytes ( RBCs ) 

2. Leucocytes ( WBCs ) 

3. Thromocytes ( Platelets ) 

  

 • All blood cells originated from pluripotent stems cells several developmental stages.

• All process of blood cell formation is called haemoposis and takes place within red blood narrow , haemoposis in the skeleton is confirned to flat bone irregular bones and the ends of long bone , the main sites are skull , ribs , sternum and pelvis . 

Lymphocyte are produced lymphoid tissue. 

Erythrocytes Or RBCs 

These are circular , biconcave and non nucleated. They have no nucleus, and there diameter is about 7 micrometre (mm) . There main function is in gas transport, mainly of O² but they also carries some CO² . 

Life span and function of erythrocytes 

Erythrocytes are produced in red bone narrow which is present in the ends of long bone. 

1. There lifespan is about 120 days. 

2. The Process of development of RBCs from pluripotent stems cells that about 7 days , and is called erythrocytes. 

3. Both vitamin B12 and golvi acid are required for red blood synthesis.

Oxygen transport - HB :- Structure , synthesis and breakdown vaccination of molicules 

1. Hb is a large complex containing a globular protein and its takes pigmented , iron containing complex call haem. 

2. Each Hb molecules contain 4 atom of iron.

3. When all four oxygen bonding sites on a Hb molecules are full described as situated. 

O² —› oxyhaemoglobin

Hb + O² —› HbO 

4. At each atom of ion can combined an O² molecules , this means that as single Hb molecules can carry upto four molecules of oxygen.

Control of erythrocytes :- 

The no. Of blood cells remain constant, which means that the bone narrow, produce erythrocytes at the rate which they are destroy, the primary stimulies to increased erythropoiesis, is hypoxia that is deficient O² supply to body cells.

This occurs when — 

The O² carrying capacity of blood is reduced by ex. — Haemorrhage breakdown ( haemolysis ) . 

 • Hypoxin increase erythrocytes formation by stimulating the product of the hormone erythtopoetin mainly by the kidneys erythrocytes.

• Stimulates an increase in the production of proerythoplast carbon release increased number of reticulocytes into the blood. 

This increase no. Of carrying capacity of blood and reverse tissue hypoxia. 

Destruct of erythocytes 

• The lifespan of erythocytes is about 120 days and their breakdown of hemolysis is carried out by phagocytosis reticuloendothelial cells, these cells are found in many tissue by the main sides of hemolysis are the spleen , bone narrow and their.

• As erythocytes ages their cell membrant become susceptive to haemolysis retained in the body and reused in the bone narrow to form new haemoglobin (Hb ) molecules.