Changes

[[Image:LH Mast cell Histology.jpg|<p>'''Mast cell'''</p>^{©Nottingham Uni 2008}]]

[[Image:LH Mast cell Histology.jpg|right|thumb|150px|<p>'''Mast cell'''</p>^{©Nottingham Uni 2008}]]

[[Image:LH Mast cells Histology.jpg|<p>'''Mast cells'''</p>^{©Nottingham Uni 2008}]]

[[Image:LH Mast cells Histology.jpg|right|thumb|150px|<p>'''Mast cells'''</p>^{©Nottingham Uni 2008}]]

==Introduction==

==Introduction==

<p>Mast cells are derived from the same stem cell line as [[Basophils|basophils]] and while they are similar to [[Basophils|basophils]] they are not identical. Mast cells are found in connective tissue and are larger than other [[Leukocytes|leukocytes]] at 15-20µm. They have cytoplasm containing a high number of large, intensely staining basophilic granules which mask the nucleus.</p>

<p>Mast cells are derived from the same stem cell line as [[Basophils|basophils]] and while they are similar to basophils they are not identical. Mast cells are found in connective tissue and are larger than other [[Leukocytes|leukocytes]] at 15-20µm. They have cytoplasm containing a high number of large, intensely staining basophilic granules which mask the nucleus.</p>

==Development==

==Development==

<p>Mast cells CFU develops in the [[Bone Marrow - Anatomy & Physiology|bone marrow]] from the myeloid set cell ([[Haematopoiesis - Overview#Colony Forming Units|CFU-GEMM]]) under the stimulation of IL-3 and Stem Cell Factor. Then under the stimulation of Il-6 and SCF the immature mast cells are formed. These then enter circulation where they remain undifferentiated. On migration into tissue they then differentiate, under stimulation by Il-4, and produce their granules. Once in the tissue mast cells may last for weeks to months.</p>

<p>Mast cells colony forming units (CFU) develop in the [[Bone Marrow - Anatomy & Physiology|bone marrow]] from the myeloid stem cell ([[Haematopoiesis - Overview#Colony Forming Units|CFU-GEMM]]) under the stimulation of IL-3 and Stem Cell Factor (SCF). Then under the continual stimulation with SCF, and with the additional stimulation with IL-6, the immature mast cells are formed. These then enter circulation where they remain undifferentiated. On migration into tissue they then differentiate, under stimulation by IL-4, and produce their granules. Once in the tissue mast cells may last for weeks to years.</p>

==Granules==

==Granules==

* Preformed mediators such as serotonin, histamine, proteoglycans, heparin and serine proteases (tryptase and/or chymase)

* Preformed mediators such as serotonin, histamine, proteoglycans, heparin and serine proteases (tryptase and/or chymase)

* Lipid mediators such as leukotrienes and prostaglandin D2

* Lipid mediators such as leukotrienes and prostaglandin D2

* Cytokines: Il-3, Il-4, Il-5, Il-6, Il-8, Il-13, Il-16 TNF-α</p>

* Cytokines: IL-3, IL-4, IL-5, IL-6, IL-8, IL-13, IL-16 and TNF-α</p>

*Chemotactic factors for both [[Neutrophils|neutrophils]] and [[Eosinophils|eosinophils]]

* Chemotactic factors for both [[Neutrophils|neutrophils]] and [[Eosinophils|eosinophils]]

<p>Histamine increases vascular permeability, mucous production and smooth muscle tone in the respiratory tract and is responsible for the itch sensation in the skin. Heparin is an anticoagulant and binds with antithrombin III and platelet factor IV to block coagulation factors. Leukotrienes like histamine are responsible for contraction of respiratory smooth muscle. Chymase plays a role in the production of angiotensin II.</p>

<p>Histamine increases vascular permeability, mucous production and smooth muscle tone in the respiratory tract and is responsible for the itch sensation in the skin. Heparin is an anticoagulant and binds with antithrombin III and platelet factor IV to block coagulation factors. Leukotrienes like histamine are responsible for contraction of respiratory smooth muscle. Chymase plays a role in the production of angiotensin II.</p>

<p>Granules are thought to produce a ground substance to facilitate collagen formation in repair of injury.</p>

<p>Mast Cell granules are thought to produce a ground substance to facilitate collagen formation which occurs during the repair of an injury.</p>

==Actions==

==Actions==

==In pathology==

==In pathology==

*Classically a cell involved in [[Acute Inflammation|acute inflammation]]

*Classically a cell involved in [[Acute Inflammation|acute inflammation]]

*Mast cell tumours of the intestine and [[Mast Cell Tumour|liver]]

*[[Neoplasia_-_Pathology#Mast_Cell_Proliferation_Disorders|Mast cell tumours]] of the intestine, liver and skin.

 

|powerpoints = [[Connective Tissue Histology resource|Tutorial about connective tissues, with slides on Mast Cells]]

 

==References==

==References==

<references />

<references />

<br>

<br>

[[Category:Blood_Cells]]

[[Category:Blood_Cells]] [[Category:Kate English reviewing]]