Assertion: Mast cells in the human body release excessive amounts of inflammatory chemicals, which cause allergic reactions.
Reason: Allergens in the environment on reaching human body stimulate mast cells in certain individuals.
(a) If both Assertion and Reason are correct and Reason is the correct explanation of Assertion.
(b) If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion.
(c) If Assertion is correct but Reason is incorrect.
(d) If both the Assertion and Reason are incorrect.
(a) If both Assertion and Reason are correct and Reason is the correct explanation of Assertion.
Explanation:
A mast cell contains many granules rich in histamine serotonin and heparin. Although best known for their role in allergy and anaphylaxis, mast cells play an important protective role as well, being intimately involved in wound healing and defense against pathogens. The symptoms of an allergic reaction develop in response to histamine. Mast cells release a large amount of histamine into the blood stream & it also act as initiator of the inflammatory response, which aids the arrival of leucocytes at a site of infection. Histamine stimulates capillary dilation increased capillary permeability, closure of bronchial tubes, mucus secretion, pain & swelling.