Enterochromaffin cells
| Enterochromaffin cell | |
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| Details | |
| Identifiers | |
| Latin | endocrinocytus EC |
| MeSH | Enterochromaffin+Cells |
| Code | TH H3.04.02.0.00029 |
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Anatomical terminology
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Enterochromaffin (EC) cells (also known as Kulchitsky cells), discovered by Nikolai Kulchitsky of Karazin Kharkiv National University. They are a type of enteroendocrine and neuroendocrine cell. They reside alongside the epithelium lining the lumen of the digestive tract and play a crucial role in gastrointestinal regulation, particularly intestinal motility and secretion. EC cells modulate neuron signalling in the enteric nervous system (ENS) via the secretion of the neurotransmitter serotonin and other peptides. As enteric afferent and efferent nerves do not protrude into the intestinal lumen, EC cells act as a form of sensory transduction.Serotonin in the ENS acts in synergy with other digestive hormones to regulate sensory and motor gastrointestinal reflexes. EC cells respond to both chemical and neurological stimuli. They are also reactive to mechanosensation and can be stimulated by a bolus moving through the bowel. Upon activation, EC cells release serotonin to act upon serotonin receptors on ENS neurons. Dependent on concentration, serotonin can then modulate peristaltic contraction and secretion through activation of smooth muscle and glands respectively.
EC cells are found aggregated in specific locations throughout the gastrointestinal tract, predominantly in the small intestine, colon and appendix. The proportion of high-density cell populations varies between species attributed to differences in dietary requirements and physiological characteristics.
EC cells are small polygonal cells located in the crypts between intestinal villi. They are discriminated from other cells of the gastrointestinal epithelial crypts by the presence of basally located granulations that contain serotonin and other peptides. Ultrastructurally, these granules are reported to vary in size and shape and are considered pleomorphic.
Most of EC cells communicate with the lumen of intestinal crypts through apical microvilli (protrusions) and are referred to as “open”. A proportion of EC cells do not protrude into the crypt lumen and are subsequently referred to as ‘closed’. EC cells typically extend down to the basal lamina with cytoplasmic extensions known to pass through the connective tissue and neighbouring glands. Tissue beneath EC cells typically contains abundant fenestrated capillaries, lymph vessels and small unmyelinated nerve fibres. Secreted serotonin can either be taken up into residing vessels (transported in the blood by platelets) or act on nerve synaptic terminals.
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