?Biology lesson 4:?
– Dr Sayan Bhattacharyya
Let us start discussing about the connective tissue, like muscles, tendons, ligaments and blood. Blood is the only liquid connective tissue.
Bliid has a pH of 7.4 , which is slightly alkaline. Blood is composed roughly of 2 components, Plasma and cellular elements. Plasma forms about 55% of blood. Plasma is composed of water, proteins, immunoglobulins and lipids, non protein nitrogenous compounds etc.
Cellular elements are composed of Red Blood corpuscles ( RBC), White Blood cells ( WBC) and Platelets.
Red Blood corpuscles are non-nucleated and contain hemoglobin. Only the RBC of camels are nucleated.RBCs function in carrying Oxygen bound with Hemoglobin and supplying it to the organs . The normal count is 5 million per ml blood. Size or diameter is about 7.2 microns. RBCs contain the different blood group antigens on their surface like ABO antigens, Duffy antigen etc.
WBCs function various things like immune protection, hypersensitivity, granuloma formation etc. Normal count is 4000- 11000 per ml blood. Size or diameter varies from 16-40 microns.
Platelets perform blood clotting after any injury to endothelium ( lining of vessels). Normal count is 1.5 – 4 laks per ml. They are very small in size ( smaller than RBC)
Serum is plasma minus fibrin. It is formed when plasma is clotted, thereby converting fibrinogen into fibrin.
Arterial blood has more Oxygen and is bright red, whereas venous blood has more of Carbon dioxide and is blackish red.
In next lesson we shall study in details about the different WBCs and their functions.