Histamine
Imagine you're at a busy airport terminal, and suddenly your flight is announced as boarding, causing a surge of passengers to rush towards the gate. Similarly, when your body detects an invader like pollen or dust, histamine acts like that announcement, causing an increase in the flow of blood and fluids to the affected area. Just as the announcement directs passengers to converge at the gate, histamine signals the body to send more blood and fluids to help fight off the perceived threat, with the mast cells being the ones 'announcing' this need by releasing histamine.
Practice Version
Histamine: A chemical that increases the flow of blood and fluids, it is secreted by mast cells. Histamine. Histamine is a natural chemical in the body that helps fight allergies by causing symptoms like sneezing and itching.