hízósejtek

Hízósejtek, also known as mast cells, are a type of white blood cell that play a crucial role in the immune system, particularly in allergic reactions and defense against pathogens. They are found in connective tissues throughout the body, especially near blood vessels, nerves, and in the skin, lungs, and digestive tract.

These cells are characterized by the presence of granules in their cytoplasm, which are packed with various bioactive mediators. The most well-known of these mediators is histamine, which is released upon activation of the mast cell. Other important substances stored in mast cell granules include heparin, proteases, and cytokines.

Mast cell activation can be triggered by a variety of stimuli, including allergens (such as pollen or pet dander), pathogens, physical injury, and certain drugs. When activated, mast cells release their granular contents into the surrounding tissue. This release, known as degranulation, leads to a cascade of physiological effects.

In allergic reactions, the binding of allergens to IgE antibodies on the mast cell surface triggers degranulation. The released histamine causes vasodilation, increased vascular permeability, and smooth muscle contraction, leading to symptoms like itching, swelling, and bronchoconstriction. Mast cells also contribute to inflammation by producing and releasing other signaling molecules that attract other immune cells to the site of injury or infection. Beyond allergy, mast cells are involved in wound healing, angiogenesis, and innate immunity. Their multifaceted roles make them important players in both health and disease.