Question

In anaphylactic shock, the substance which causes the dilation of blood vessels and capillary leakage is
A. Adrenaline
B. Benadryl
C. Histamine
D. Albumin

Answer 1

Hint: Anaphylaxis means a whole-body allergy which can be very severe. Allergen is the toxin such as the sting of an insect, poison of a snake etc which causes the allergy. As a result of the allergen, the immune system becomes sensitized.

Complete answer:
Our body has immune cells which fight against the diseases. Immune system has many cells like macrophages, mast cells, WBCs which are present in the blood and lymph that helps in fighting against the toxins or foreign antigens. When a pathogen or an allergen is exposed, our body responds in several areas. The antibodies are produced which neutralises the effect of the antigen. In case of allergy, immunoglobulin E or IgE is produced in reaction to the allergen. The IgE binds with the mast cells which facilitate the production of various chemicals like serotonin, histamines, heparin etc.
In case of shock, the histamines cause the dilation of the blood vessels which lowers the blood pressure. It also leads to the leakage of fluids from the bloodstream.
Adrenaline is the hormone which is released by the adrenal gland when the body is in danger. It stimulates the sympathetic and parasympathetic nerves.
Benadryl- Benadryl is an anti allergy which is used to relieve the symptoms of allergy.
Albumin- It is the protein which is produced by the liver. It helps in keeping the fluid in the bloodstream so that it doesn’t leak into various tissues.

Hence the correct answer is option C.

Note –
Histamine is released by the WBC in the bloodstream. It helps in regulating the physiological processes in the gut and also acts as a neurotransmitter. Its action can make us sneeze, tear etc.