Question

An insect bite may result in inflammation of that spot. This inflammation is triggered by the alarm chemicals
A. Histamine and dopamine
B. Histamine and kinins
C. Interferons and opsonin
D. Interferons and histones.

Answer 1

Hint: An inflammation is basically a swelling. The chemical substances which mediate the process of inflammation are known as the mediators of inflammation. These mediators are responsible for the itchiness, redness, pain and swelling at the site of inflammation.

Complete answer:
The five classical signs of inflammation are:
-Rubor- Redness
-Calor- Increased temperature at the site
-Dolor- Pain
-Tumor- Swelling
-Functio laesa – Loss of function
Insect bite inflammation is an acute process. When an insect bites, it injects formic acid at the site. This formic acid is responsible for the effects caused at the site. At the site of an insect bite, there is redness, heat, pain and swelling. At this site, there is release of the mediators of inflammation. These mediators are released by macrophages, mast cells, endothelial cells and other inflammatory cells.
The most important mediator released is histamine. It has the central role in itching at the site. The mast cells are the major inflammatory cells that release histamine. Basophils also secrete histamine. Histamine increases the vascular permeability leading to the leakage of proteins from vessels.
Another such mediator released are the kinins. Kallikreins are responsible for the release of kinins. Kinins tend to increase the blood flow to the area of the bite which is responsible for the redness of the site.
Therefore, the correct answer is Option B.

Note: Kinins are produced and secreted by the liver cells. There are other sites of production as well, such as the renal and the secretory cells. The other inflammatory mediators are tryptase, cytokines, interleukines, cytokines, etc. The primary cause of the release of mediators is tissue injury.