GK Science: All about Human Blood

Blood is a fluid connective tissue. It is 6.8 litres in man and 500 ml less in woman. 6 – 8% of body weight ( pH 7.4 ).

Blood is made up of : 

1. Red Blood Corpuscles ( RBC)

• Also called Erythrocytes, disc – shaped ( for increased Surface Area ), no nucleus contains a pigment called Haemoglobin, which gives blood its Red Color.
• Life of RBC is 120 days after which they are broken down in spleen or liver.

2. White Blood Corpuscles (WBC)

• Also called Leucocytes, rounded, with a nucleus, far less numerous than RBCs ( 1 : 400 – 500 ) ( 5,000 – 10,000 / cu mm ), life 3 – 4 days, soldiers of body’s defence system.

3. Platelets

• Also called Thrombocytes, formed in bone marrow, about 250,000 / cu mm of blood, life 3 – 7 days, sets off blood clotting.

4. Plasma (65% of total blood)

• Plasma transports nutrients from the small intestine to the body tissues, and return the waste material to the kidneys, where it is filtered out.
• Regulates pH of blood.

Blood Groupings:

• Father of Blood Grouping: Karl Landsteiner ( Australian pathologist ). He discovered A, B and O blood groups in 1900.
• Possible Blood Groups: