Difference between revisions of "Enterocytes, Epithelial Renewal"
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m (Text replace - "[[Small Intestine - Anatomy & Physiology|" to "[[Small Intestine Overview - Anatomy & Physiology|") |
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* Enterocytes are usually shed after 2-8 days. | * Enterocytes are usually shed after 2-8 days. | ||
| − | * To replace enterocytes. epithelial progenitor cells in the crypts of the [[Small Intestine - Anatomy & Physiology|small intestine]] continually divide. | + | * To replace enterocytes. epithelial progenitor cells in the crypts of the [[Small Intestine Overview - Anatomy & Physiology|small intestine]] continually divide. |
** New epithelial cells move up towards the surface (i.e. the tip of the villus). | ** New epithelial cells move up towards the surface (i.e. the tip of the villus). | ||
** As cells move up, they differentiate and lose the ability to divide. | ** As cells move up, they differentiate and lose the ability to divide. | ||
Latest revision as of 12:56, 7 September 2010
- Enterocytes are usually shed after 2-8 days.
- To replace enterocytes. epithelial progenitor cells in the crypts of the small intestine continually divide.
- New epithelial cells move up towards the surface (i.e. the tip of the villus).
- As cells move up, they differentiate and lose the ability to divide.
- When epithelial cells are lost (rather than shed), the damage is repaired.
- Minor loss results in the lateral migration of adjacent cells.
- Repair within minutes.
- More major loss results in contraction of the villus, and cells migrate across intercrypt surface.
- Minor loss results in the lateral migration of adjacent cells.
- Epithelial renewal is in a state of dynamic equilibrium.
- Enterocyte production in crypts = shedding from villus tip into lumen.
- Disruption of this equilibrium by any disease can cause lesions of the mucosa and villi.
- E.g. villus atrophy.