Mast Cells- Definition, Structure, Immunity, Types, Functions


Mast cells are a type of white blood cell that play a vital role in the immune system. They are found in various tissues throughout the body, especially in the skin, mucous membranes, and connective tissues. Mast cells are involved in both innate and adaptive immunity, as well as in allergic reactions and inflammation. Mast cells have the ability to release various substances, called mediators, that can affect the function of other cells and organs. Some of these mediators include histamine, heparin, cytokines, and proteases. Mast cells can also interact with other immune cells, such as B cells, T cells, dendritic cells, and eosinophils.

Mast cells are derived from hematopoietic stem cells in the bone marrow. They undergo differentiation and maturation in the peripheral tissues under the influence of various factors, such as cytokines and growth factors. Mast cells can be classified into two main types: mucosal mast cells and connective tissue mast cells. These two types differ in their location, morphology, granule content, and response to stimuli. Mast cells can also be further subdivided into subtypes based on their expression of surface markers and receptors.

Mast cells are important for maintaining the homeostasis of the body and protecting it from pathogens and foreign substances. However, mast cells can also contribute to pathological conditions when they are overactivated or dysregulated. For example, mast cells can cause allergic reactions, such as anaphylaxis, asthma, urticaria, and rhinitis, by releasing excessive amounts of histamine and other mediators. Mast cells can also be involved in chronic inflammatory diseases, such as atopic dermatitis, inflammatory bowel disease, rheumatoid arthritis, and multiple sclerosis, by producing pro-inflammatory cytokines and chemokines. Furthermore, mast cells can influence tumor growth and angiogenesis by secreting growth factors and proteases.

In this article, we will discuss the structure, immunity, types, and functions of mast cells in more detail. We will also explore some of the clinical implications of mast cell activation and dysfunction.