Stages of blood formation in the embryo and fetus, Function of R.B.C's, Leukocytes W.B.C's:

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Stages of blood formation in the embryo and fetus

There are three successive stages of blood formation in the embryo and fetus.

1. Mesoblastic haemopoiesis:-

It is the blood formation and occurs in the first two months of embryonic life. In this case most of the cells are formed outside the embryo. This stage diminished in a human embryo of nine weeks.

2. Hepatic- haemopoiesis:-

This constitutes the see and stage and includes. The splenic and thy-mic blood formation this stage occurs from the end to fifth month.

3. Myeloid haemopoiesis :-

This stage beings at the fifth with the establishment of the presental circulation. In this stage first liver is responsible for the formation of R.B.C's and the bone marrow for the W.B.C's later in the bone marrow take the responsibility of the formation of R.B.C's

Function of R.B.C's

1. Transport of Gases:

R.B.C's play an important role in the transport of gases such as O2 and CO2.

i. Transport of O2:

When we inhale O2. Then this O2 reach the lungs where hemoglobin which is the chief component of erythrocyte combines with O2 to form oxy-hemoglobin. Actually the function of erythrocytes is to carry the O2 in the form of oxy-hemoglobin to various time of the body. After reaching the tissues again the O2 is released.

Hb+O2--------> HbO2

HbO2---------> Hb+O2

ii. Transport of CO2:

So after the oxidation of glucose Co2 is released which is not required in the tissues. This Co2 is carried back by R.B.C to the lungs in the form of carb-hemoglobin. From the lungs the Co2 passes out.

2. Energy Production:

R.B.C's also play an important role in the production of energy indirectly because after carries O2 by erythrocytes to the tissues where oxidation of glucose takes places and energy is produced which is required for normal body function.

C6H12O6 + 6 O2 -----------> 6-O2 + 6+O2 = Energy

If R.B.C's left the function of O2 transport no energy will be produced because no oxidation of glucose takes place.

3. Acid-Base Balance:

They also help to maintain acid base balance. It is carried out by the buffering action for example bicarbonates and plasma protein. The buffer action of plasma protein is of great importance which carries about 10% of CO2. In lungs O2Hb is formed from reduced Hb and H+ are released react with HCO2- to give H2CO3. As inside the lungs the cone of CO2. So the equilibrium, the right and CO2 passes out.

H(+) + HCO3(-) <--------> H2CO3 <-----> H2O - CO2

Leukocytes W.B.C's:

Leukocytes are the white blood corpuscles and are the seemed constituent of formed elements.

Chemistry: Since the leukocytes are the typical cells, they contain water, nucleoprotein, albumin, globulin and other protein, lipids (especially cholesterol phospho lipids and fat) and other soluble organic substances and inorganic salts. They also possess a variety of enzymes and undoubtedly harmonies and vitamins.