Question

When a mast cell reacts to an irritation, which of the following chemicals does it release? A. Collagen B. Histamine C. Hyaluronic Acid D. Myelin

Answer 1

When a mast cell reacts to an irritation, it releases the chemical histamine. Therefore, the correct answer is B. Histamine.

Step-by-step explanation:

Mast cells, a type of immune cell, play a crucial role in the body's defense against irritants and pathogens. When these cells encounter an irritation or allergen, they release various substances to initiate an immune response. Among these substances, histamine is a key player. Histamine is a signaling molecule that triggers inflammatory responses, such as increased blood flow and permeability of blood vessels, leading to the characteristic symptoms of allergy, such as itching, swelling, and redness.

Histamine release is a tightly regulated process. The mast cell's response involves the activation of specific receptors, which then trigger a cascade of intracellular events leading to histamine release. Once released, histamine binds to its receptors on nearby cells, such as blood vessels and smooth muscle cells, eliciting the characteristic allergic reactions. Understanding this process is crucial for developing effective treatments for allergies and inflammatory conditions.

In summary, mast cells release histamine in response to irritation, and this histamine release is a fundamental step in the body's immune response. The intricate molecular mechanisms underlying this process highlight the complexity of the immune system's regulation and its ability to mount targeted responses to potential threats.

Answer 2

When a mast cell reacts to an irritation, it releases B. Histamine. Therefore, option (B) is the correct answer.

Histamine is a key mediator in allergic reactions and is involved in the body's immune response to irritants. When mast cells encounter an allergen or irritant, they degranulate, releasing histamine and other chemicals.

Histamine increases the permeability of the capillaries to white blood cells and other proteins, which allows them to engage pathogens in the infected tissues. It is responsible for various allergy symptoms like itching, swelling, and redness.

This is in contrast to collagen, hyaluronic acid, and myelin, which have different functions in the body and are not primarily released by mast cells in response to irritation.