Blood cells & its Types-White blood cells,Red blood cells and Platelets

Blood

It is a specialized body fluid (a connective tissue) that is composed of liquid called blood plasma or blood cells. The blood weight in human body is 1/12^th of our body. There is 5 liter blood in adult body. The fit person contains 55% by volume of blood, and cells or cells like bodies are about 45% by volume of blood.

Blood Plasma

Plasma is primly water which contain proteins, metabolites and wastes are dissolved. Water 90-92% of plasma and 8-10% are dissolved substances. salts make 0.9% of plasma, by weight. Salts of bicarbonates are present in considerable amount. Proteins make7-9% by weight of plasma. The important proteins are antibodies, fibrinogen and albumin etc. Blood contains digestive food, nitrogen wastes and hormones. Respiratory gases i.e. CO2 and O2 are present in plasma.

Blood cells and cell-like bodies

These contain;

• Red blood cells
• White blood cells
• platelets 

Red Blood cells

These are also called Erythrocytes. These are numerous of blood cells. In males a cubic millimeter of blood contains 5-5.5 million of RBCs, but in female it is 4-4.5 million of RBCs. When RBCs are formed they have nucleus but when they are mature their nucleus is lost. And after that RBC enter in the blood. About 95% of cytoplasm of RBCs is filled with hemoglobin, which transport O2 and small amount of CO2. The remaining 5% are of enzymes, salts and other proteins. RBCs contain elastic cells membranes. In embryonic, they are formed in liver and spleen. In adult, they are formed in red bone marrow of short and flat bones. Average life of RBCs is four months (120 Days).

White Blood cells

These cells are colorless. WBCs are also called Leukocytes. These cells are migrating out into tissue fluid. One cubic millimeter contains 7000-8000 WBCs. Their life is months –years depending upon the body needs. WBCs are the defence agents in the body.

Types

• Granulocytes

They have granular cytoplasm. These include neutrophils (destroy small particles by phagocytosis), eosinophils (kill parasites) and basophils (prevent blood clotting).

• Agranulocytes

They have clear cytoplasm and include monocytes (produced macrophages) and B&T Lymphocytes (kill germs by produce antibodies).

Platelets

They are not cells, but are fragments of large cells of bone marrow, called megakaryocytes. They don’t have any nucleus and pigment. One cubic millimeter of blood contains 250000 platelets. The average life of platelets is about 7-8 days. It also helps in blood clotting. The make temporary seal at damage area of body.