Question

Which leukocytes release histamine, serotonin, and heparin?
(a) Eosinophils
(b) Basophils
(c) Monocytes
(d) Neutrophils

Answer 1

Hint: The leukocytes are an essential part of the defense mechanism of the body. There are two types of leukocytes. agranulocytes and granulocyte. A sub- type of granulocyte releases histamine and serotonin to induce inflammation and heparin to prevent blood clotting.

Complete step by step answer:
Leucocytes also are known as White Blood Cells (WBCs) are the immune cells of the body that circulate in the blood and the lymphatic system. There are two types of leukocytes- Granulocytes and Agranulocytes
- Granulocytes are of 3 types- Neutrophils, Eosinophils, and Basophils
- Agranulocytes are of 2 types- Lymphocytes and Monocytes
Basophils.
- Basophils are granulocytes formed from the myeloid cell line of the bone marrow.
- They are 14- 16µm in diameter with a bi- lobed and S- shaped nucleus.
- These cells are found in the peripheral blood and have roughly 2 weeks of life- span.
- High basophil count in blood is seen during allergic reactions.
Functions of basophils
- During allergic reactions, the immune system is exposed to an allergen which causes basophils to release histamines and serotonin as a counter- attack to mediate the allergy. These histamines cause local inflammatory responses by interactions with the IgE antibody
- Basophils also secrete heparin- an anticoagulant that prevents blood clotting caused by certain medical conditions.
So, the correct answer is Basophils.

Note: Basophils are not to be confused with Mast cells, although both share several characteristics regarding their functions and development. Mast cells are born in the bone marrow and mature in the peripheral tissue whereas basophils mature in the bone marrow and circulate in the peripheral tissue as mature cells.