BLOOD (FOR NEET, SSC AND UPSC)
Blood is composed of blood cells or corpuscles, suspended in clear, straw-colored liquid called plasma.
The cells include:
- Red Blood Cells or Corpuscles (Erythrocytes)
- White Blood Cells or Corpuscles (Leucocytes)
- Platelets or Thrombocytes
These cells make 45% of the total blood volume, rest 55% is made up of the plasma that contains salts, hormones, vitamins, proteins etc.
ERYTHROCYTES OR RED BLOOD CORPUSCLES
They are abbreviated as RBC. These are the enucleated cells of our body. They are biconcave and discoid in shape. They possess a life span of only 120 days. There formation takes place in the bone marrow of an individual; erythropoietin hormone secreted by the kidney stimulates this process. RBC contain a protein pigment, haemoglobin which combines with oxygen and helps in oxygen transport throughout our body. Oxygenated blood is red in color and deoxygenated blood is blue in colour.
LEUCOCYTES OR WHITE BLOOD CORPUSCLES
They act as the soldiers of the body; because they help us in fighting against infections There number is less in comparison to the RBCs. They are categorized as:
- Agranulocytes: They do not contain granules in the cytoplasm. It includes-
- BASOPHILS – They get stained by the basic dyes.
- EOSINOPHILS – There number is increased at the time of infection.
- NEUTROPHILS – They do not stained by any dye, as they are neutral.
- Granulocytes: They contain granules in the cytoplasm. It includes-
- MONOCYTES- They helps in the phagocytosis and matures to form the macrophages.
- LYMPHOCYTES – These are the main cells of lymphatic system in our body. They can be of 2 types: B-lymphocytes and T-lymphocytes.
PLATELETS OR THROMBOCYTES
These cells are also formed in the bone marrow and they help in the clotting of blood.
This is the liquid component of the blood and consists of water, dissolved proteins, sugar, salts, hormones and other substances. The main plasma proteins are albumins, globulins, fibrinogen and prothrombin.
Q.1. Red Blood Cells are also known as:
Q.2. The red colored pigment of the human blood is:
Q.3. The soldiers of the human body are:
Q.4. The cells that help in clotting are:
Q.5. Synthesis of blood takes place in:
- Bone marrow
Q.6. Lymphatic system is made up of:
Q.7. RBCs are: