Difference between revisions of "Rectum - Anatomy & Physiology"
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*Exists dorsal to the [[Reproductive System|reproductive organs]], [[Urinary System - Anatomy & Physiology|bladder]] and urethra. | *Exists dorsal to the [[Reproductive System|reproductive organs]], [[Urinary System - Anatomy & Physiology|bladder]] and urethra. | ||
*The cranial portion of the rectum is attached to the dorsal body wall by a short mesorectum which is a continuation of the mesocolon. | *The cranial portion of the rectum is attached to the dorsal body wall by a short mesorectum which is a continuation of the mesocolon. | ||
| + | *The mesocolon is reflected to continue with the parietal peritoneum of the pelvic cavity and to cover the urogenital organs ventrally. | ||
| + | **This forms the '''rectogenital pouch'''. | ||
| + | **Therefore the most distal part of the rectum is retroperitoneal. | ||
| + | ***This distal, retroperitoneal part is directly attached to the vagina in the female and to the urethra in the male. | ||
| + | *The '''anal canal''' joins the bowel to the exterior. | ||
| + | **This is a short passage derived from the proctodeum (formed by invagination of the surface ectoderm). | ||
| + | *At the rectoanal junction, the lumen is constricted by longitudinal folds in the mucosa. | ||
| + | **These are normally pressed together to occlude the lumen. | ||
| + | *There are ''two'' anal sphincters: | ||
==Function== | ==Function== | ||
Revision as of 08:16, 12 July 2008
Introduction
Structure
- Exists dorsal to the reproductive organs, bladder and urethra.
- The cranial portion of the rectum is attached to the dorsal body wall by a short mesorectum which is a continuation of the mesocolon.
- The mesocolon is reflected to continue with the parietal peritoneum of the pelvic cavity and to cover the urogenital organs ventrally.
- This forms the rectogenital pouch.
- Therefore the most distal part of the rectum is retroperitoneal.
- This distal, retroperitoneal part is directly attached to the vagina in the female and to the urethra in the male.
- The anal canal joins the bowel to the exterior.
- This is a short passage derived from the proctodeum (formed by invagination of the surface ectoderm).
- At the rectoanal junction, the lumen is constricted by longitudinal folds in the mucosa.
- These are normally pressed together to occlude the lumen.
- There are two anal sphincters: