Question

Diapedesis means
A. Formation of WBC
B. Formation of RBC
C. Process by which lymphocyte squeeze through thin capillary
D. Movement of food in gut

Answer 1

Diapedesis is the passage of blood cells through the intact walls of capillaries. Blood cells are the cells of the blood which include Red Blood Cells (RBCs), White Blood Cells (WBCs) and Platelets. RBCs contain haemoglobin which helps in transport of oxygen to the body cells. WBCs provide immunity to the body. Platelets help in the clotting of the blood.

Complete Answer:
- Diapedesis is also called as the leukocyte extravasation or leukocyte adhesion cascade. Leukocyte is the other name of White Blood Cells.
- Diapedesis is the movement of leukocytes out of the circulatory system and towards the site of tissue damage or infection as White Blood cells help in providing defense to the body.
- Diapedesis is a part of innate (by birth) immune response.
- The size of the leukocytes is small for this reason they can pass easily through the capillaries. The flow of the leukocytes is unpredictable sometimes.

White blood cells: White blood cells are also called the leukocytes. These cells protect the body against illness and disease. White blood cells are of five types-
1. Monocytes – Monocytes help to break down the bacteria.
2. Lymphocytes – Lymphocytes create antibodies to fight against bacteria, viruses and other harmful invaders or pathogens.
3. Neutrophils – Neutrophils kill and digest the bacteria and fungi.
4. Basophils – Basophils become active when any infectious agents invade the blood. These cells secrete some chemicals like histamine which is a marker of allergic disease and help the immune system to spread the control of particular allergens.
5. Eosinophils – Eosinophils attack and kill parasites and cancerous cells and help with allergic responses.

Additional information:
- Formation of RBCs is called Erythropoiesis (hematopoiesis – formation of blood cells). RBC formation takes place in the bone marrow.
- Formation of WBCs is called as Hematopoiesis which means the formation of blood cells.
Movement of food in the gut is called peristalsis.

Hence, option C is the correct answer for this question.

Note: Leukocytes adhesion deficiency is a genetic disease which is associated with the defect in the leukocyte extravasation process. This disease is caused by the defective integrin Beta2 chain. This impairs the ability of the leukocytes to stop and undergo diapedesis.