Blood is the fluid connective tissue that acts as the medium to transport nutrients and oxygen from one part to the other in a body. It contributes to 8% of the total body weight of an organism. Blood consists of two parts – the plasma and the blood elements.

Plasma –

The plasma of the blood consists of all the essential nutrients and substances including proteins, amino acids, nitrogenous substances and wastes, in short everything other than the blood cells.

The blood corpuscles and the platelets comes under the group – the blood elements.

The different types of blood corpuscles are :

1. Red blood cells / erythrocytes –

· These are biconcave in shape

· These lack nucleus and any other organelles

· These help in the transport of oxygen and carbon dioxide

· These contain an iron rich product – hemoglobin, that imparts blood its red color

2. White blood cells / Leucocytes –

· These are colourless cells

· These can be sub divided into granulocytes and agranulocytes

· These contribute in the defence of the body

· The granulocytes includes –

a) Eosinophils

b) Neutrophils

c) Basophils

And the a granulocytes includes –

a) Monocytes

b) Lymphocytes

3. Platelets / thrombocytes –

· These are large disc shaped cells

· These contribute in the clotting of the blood

Thus, this was the composition of the blood. I hope this helps.