::

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 is known as a connective tissue because of its role in the body, that is, transport of gases and nutrients. As such it connects different parts of the body, hence the category of connective tissue.

Blood consists of two parts – the plasma and the blood elements.

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 – haemoglobin, that imparts blood its red colour

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 –

· These are large disc shaped cells

· These contribute in the clotting of the blood

Functions of the blood –

· It supplies oxygen to cells and tissues

· It collects carbon dioxide from the tissues and revert it to the lungs to be exhaled out

· It transports the essential nutrients like amino acids, fatty acids and glucose to cells

· it transports hormones from one part of the body to another

· the white blood cells present in the blood help in defence mechanism of the body

· the platelets help in the clotting of blood and protects the wound from infections

Thus, blood belongs to the category of connective tissues because of its properties and origin. I hope this answer helps.