Mast cells originate from bone marrow stem cells. They are produced in the bone marrow and then circulate in the bloodstream as undifferentiated precursor cells. These precursor cells, known as mast cell progenitors, leave the bloodstream and migrate to various tissues throughout the body.
Once they reach the tissues, mast cell progenitors undergo further maturation and differentiation into fully functional mast cells. The final maturation steps occur in the connective tissues, where mast cells are typically found in proximity to blood vessels and nerves.
The maturation process involves the acquisition of specific surface markers and the development of characteristic granules containing various bioactive molecules, such as histamine and proteases. Mast cells are strategically located in various tissues, including the skin, lungs, gastrointestinal tract, and mucous membranes, where they play a key role in immune responses and allergic reactions.
- Function: Technically, mast cells are not granulocytes because they differentiate from a progenitor to the GMP (granulocyte-myeloid progenitor population). However, mast cells share similarities with granulocytes, especially basophils, in their ability to release histamine and other inflammatory mediators.
- Immune Response: Mast cells play a crucial role in allergic responses and immune defense. Upon activation, they release histamine and other molecules that contribute to inflammation, vasodilation, and the recruitment of immune cells to the site of infection or injury.
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Source: ChatGPT response prompted and edited by Joel Graff.
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