Difference between revisions of "Caecum - Anatomy & Physiology"

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Introduction

Dog caecum, ileum and colon - Copywright RVC 2008

The caecum is a blind ending diverticulum of the large intestine and exists at the junction of the ileum and the ascending colon. It's size and physiological importance vary between species. It is a site of microbial fermentation, absorption and transportation.

Structure

It communicates with the ileum via the ileal orifice and with the colon via the caecocolic orifice.
It consists of a base, body and apex, the apex being the blind-ending portion.
It is attached to the ileum by a fold of peritoneum called the ileocaecal fold.

Function

Microbial Fermentation

The contribution of this is species dependant.

Absorption

VFAs that are produced are absorbed here.

Transportation

Segmental contractions facilitate absorption and microbial actitivity.
Every 3-5 minutes, segmentation is replaced by mass movements. This is similar to peristalsis, but large portions of the caecum contract simultaneously to move chyme into the colon.

Histology

No villi
Mucosa has mucous glands
- Lamina muscularis has large lymphatic nodules.
Submucosa has no glands.

Species Differences

Canine

On the right side of the abdomen.
Unique because it has no direct connection to the ileum.
Short and held in a spiral shape against the ileum by the ileocaecal fold.
Little microbial fermentation takes place.

Ruminant

On the right side of the abdomen in the supraomental recess
The apex points caudally.
Relatively small and featureless: there are no taenia or haustra.
Some microbial fermentation takes place.

Horse

A significant amount of fermentation takes place.

Pig

On the left side of the abdomen, with the apex pointing caudoventrally.
Cylindrical in shape.
Three taenia are present
- The ventral taenia provides the attachment for the ileocaecal fold.
- The lateral and medial taenia are free.

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-{{OpenPagesTop}}
+<big><center>[[Alimentary - Anatomy & Physiology|'''BACK TO ALIMENTARY - ANATOMY & PHYSIOLOGY''']]</center></big>
-==Overview==
+<big><center>[[Large Intestine - Anatomy & Physiology|'''BACK TO LARGE INTESTINE - ANATOMY & PHYSIOLOGY''']]</center></big>
-[[Image:opendogcaecum.jpg|thumb|right|250px|Dog caecum, ileum and colon - © RVC 2008]]
-[[Image:Caecum and appendix of gibbon.JPG|thumb|right|250px|Gibbon caecum and appendix- © RVC 2008]]
-The cecum is a blind ending diverticulum of the large intestine and it exists at the junction of the '''[[Ileum - Anatomy & Physiology|ileum]]''' and the ascending '''[[Colon - Anatomy & Physiology|colon]]'''. Its size and physiological importance varies between species. It is a site of microbial fermentation, absorption and transportation.
+==Introduction==
+[[Image:opendogcaecum.jpg|thumb|right|150px|Dog caecum, ileum and colon - Copywright RVC 2008]]
+The caecum is a blind ending diverticulum of the large intestine and exists at the junction of the ileum and the ascending colon. It's size and physiological importance vary between species. It is a site of microbial fermentation, absorption and transportation.
 ==Structure==
-The caecum communicates with the [[Ileum - Anatomy & Physiology|ileum]] via the '''ileal orifice''' and with the [[Colon - Anatomy & Physiology|colon]] via the '''caecocolic orifice'''.
+*It communicates with the ileum via the ileal orifice and with the colon via the caecocolic orifice.
-It consists of a base, body and apex. The apex is the blind-ending portion. It is attached to the ileum by a fold of peritoneum called the '''ileocaecal fold'''.
+*It consists of a base, body and apex, the apex being the blind-ending portion.
+*It is attached to the ileum by a fold of peritoneum called the '''ileocaecal fold'''.
 ==Function==
-'''1. Microbial Fermentation'''
+'''Microbial Fermentation'''
-The contribution of this is [[#Species Differences|species dependant]]. The products of fermentation are [[Volatile Fatty Acids|volatile fatty acids (VFAs)]].
+*The contribution of this is species dependant.
-'''2. Absorption'''
+'''Absorption'''
-VFAs that are produced are absorbed here.
+*VFAs that are produced are absorbed here.
-'''3. Transportation'''
+'''Transportation'''
-Segmental contractions facilitate absorption and microbial activity. Every 3-5 minutes, segmentation is replaced by ''mass movements''. This is similar to peristalsis, but large portions of the caecum contract simultaneously to move chyme into the [[Colon - Anatomy & Physiology|colon]].
+*Segmental contractions facilitate absorption and microbial actitivity.
+*Every 3-5 minutes, segmentation is replaced by ''mass movements''. This is similar to peristalsis, but large portions of the caecum contract simultaneously to move chyme into the colon.
+==Histology==
+*No villi
+*Mucosa has mucous glands
+**Lamina muscularis has large lymphatic nodules.
+*Submucosa has no glands.
 ==Species Differences==
 ===Canine===
-In canine species, the caecum is on the right side of the abdomen. It is unique because it has no direct connection to the [[Ileum - Anatomy & Physiology|ileum]]. It is short and held in a spiral shape against the ileum by the '''ileocaecal fold'''. Little microbial fermentation takes place.
+*On the right side of the abdomen.
+*Unique because it has no direct connection to the ileum.
+*Short and held in a spiral shape against the ileum by the ileocaecal fold.
+*Little microbial fermentation takes place.
 ===Ruminant===
-In the ruminant, the caecum is found on the right side of the abdomen, in the '''supraomental recess'''. The apex points caudally. It is relatively small and featureless, there are no taenia or haustra. Some microbial fermentation takes place.
+*On the right side of the abdomen in the supraomental recess
+*The apex points caudally.
-===[[Alimentary System  - Horse Anatomy|Equine]]===
+*Relatively small and featureless: there are no taenia or haustra.
-A significant amount of fermentation takes place in the equine caecum.
+*Some microbial fermentation takes place.
-contains haustra & tenia, very large, and point cranially.
-===Porcine===
+===[[Hindgut Fermenters - Horse - Anatomy & Physiology|Horse]]===
-The caecum is on the left side of the abdomen, with the apex pointing caudoventrally. It is cylindrical in shape and there are three taenia present. The ''ventral'' taenia provides the attachment for the '''ileocaecal fold'''. The ''lateral'' and ''medial'' taenia are free.
+*A significant amount of fermentation takes place.
-==Histology==
+===Pig===
+*On the left side of the abdomen, with the apex pointing caudoventrally.
-The caecum has no villi. The '''mucosa''' has mucous glands, the '''lamina muscularis''' has large lymphatic nodules and the '''submucosa''' has no glands.
+*Cylindrical in shape.
+*Three taenia are present
+**The ''ventral'' taenia provides the attachment for the ileocaecal fold.
+**The ''lateral'' and ''medial'' taenia are free.
 ==Links==
+*[[The Small and Large Intestines|The Small and Large Intestines]]
-'''Click here for information on the [[Intestines, Small and Large - Pathology|pathology of the Small and Large Intestines]]'''
+*[http://stream2.rvc.ac.uk/Anatomy/bovine/Pot0048.mp4 Pot 48 The Small and Large intestine of the Ruminant]
+*[http://stream2.rvc.ac.uk/Anatomy/bovine/Pot0052.mp4 Pot 52 Lateral view of the Abdomen of a young Ruminant]
-'''Click here for information on the [[Peyer's Patches - Anatomy & Physiology|Peyer's Patches]]'''
+*[http://stream2.rvc.ac.uk/Anatomy/equine/Pony_abdomen.mp4 Lateral View of the Equine Abdomen]
+*[http://stream2.rvc.ac.uk/Frean/Pony/left_topography.mp4 Left Sided topography of the Equine abdomen]
-{{Template:Learning
+*[http://stream2.rvc.ac.uk/Frean/Pony/right_topography.mp4 Right sided topography of the Equine Abdomen]
-|flashcards = [[Caecum - Anatomy & Physiology - Flashcards|Caecum]]
+*[http://stream2.rvc.ac.uk/Anatomy/feline/pot0357.mp4 Pot 357 The Feline Abdomen]
-|videos = [[Video: Ruminant small and large intestine potcast|Ruminant small and large intestine potcast]]<br>[[Video: Ruminant abdomen potcast|Ruminant abdomen potcast]]<br>[[Video: Foal gastrointestinal tract potcast|Foal gastrointestinal tract potcast]]<br>[[Video: Abdominal viscera of the horse dissection|Abdominal viscera of the horse dissection]]<br>[[Video: Equine left-sided abdominal and thoracic topography dissection|Equine left-sided abdominal and thoracic topography dissection]]<br>[[Video: Equine left-sided abdominal and thoracic topography dissection 2|Equine left-sided abdominal and thoracic topography dissection 2]]<br>[[Video: Ovine large and small intestine dissection|Ovine large and small intestine dissection]]<br>[[Video: Porcine abdomen dissection|Porcine abdomen dissection]]
+*[http://stream2.rvc.ac.uk/Frean/sheep/LargeSmallIntestine.mp4 Small and Large intestine of the Sheep]
-}}
+*[http://stream2.rvc.ac.uk/Anatomy/swine/Pig_abdomen.mp4 The Porcine Abdomen]
-==Webinars==
-<rss max="10" highlight="none">https://www.thewebinarvet.com/gastroenterology-and-nutrition/webinars/feed</rss>
-[[Category:Large Intestine - Anatomy & Physiology]]
-[[Category:A&P Done]]