Blood is a fluid connective tissue. The quantity of blood in the human body is 7% of the total weight. This is dissolution of base whose pH value is 7.4. There is an average of 5-6 liters of blood in human body. But, Female contains half-litre of blood less in comparison to male.
Blood is consisting of 2 parts – A) Plasma; B) Blood corpuscles.
A) Plasma: This is the liquid part of blood contains 60%. Its 90% parts is water, 7% protein, 0.9% salt and 0.1% is glucose. Remaining substances are in a very low quantity.
Functions of Plasma: transportation of digested food, hormones, excretory product, etc from the body takes place through plasma.
Serum: when Fibrinogen & Protein is extracted out of plasma, the remaining is called serum.
B) Blood Corpuscles: This is remaining 40% part of the blood which is divided into 3 parts-
i) Red Blood Corpuscles (RBCs); ii) White Blood Corpuscles (WBCs) and iii) Blood Platelets.
i) Red Blood Corpuscles (RBC):
- RBC of a Mammal is biconcave. There is no nucleus in it exception in camels and lama. RBC is formed in Bone marrow.
- Its lifespan is from 20 days to 120 days.
- Its destruction takes place in liver & spleen. Therefore, Liver is called grave of RBC.
- It contains haemoglobin, in which haeme iron containing compound is found and due to this color of blood id red.
- Globin is a proteinous compound which is extremely capable of combining with oxygen and Co2.
- The iron compound found in haemoglobin is Haematin.
- The main function of RBC is to carry oxygen to all cells of the body and bring back the Co2.
- Anaemia disease is caused due the deficiency of haemoglobin.
- At the time of sleeping, RBC reduced by 5% and people who are at the height of 4200 metres, RBC increases by 30% in them.
ii) White Blood Corpuscles (WBC) or Leucocytes:
- In shape & constitution, this is similar to Amoeba. Nucleus is present in it.
- Its formation takes place in bone marrow, lymph node and sometimes in liver & spleen.
- Its life span is from 1 to 2 days.
- Its main function is to protect the body from the disease.
The ratio of RBC: WBC is 600:1.
iii) Blood Platelets or Thrombocytes:
- It is found only in the blood of human & other mammals.
- There is no nucleus in it.
- Its formation takes place in Bone marrow.
- Its life span is from 3-5 days. It dies in the spleen.
- Its main function is to help in clotting of blood.
Functions of Blood:
- To control the temperature of the body and to protect the body from diseases.
- Clotting of blood.
- Transportation of O2, CO2, digested food, conduction of hormones, etc.
- To help is establishing co-ordination among different parts.