Difference between revisions of "Jejunum - Anatomy & Physiology"

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<big><center>[[Alimentary - Anatomy & Physiology|'''BACK TO ALIMENTARY - ANATOMY & PHYSIOLOGY''']]</center></big><big><center>
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[[Small Intestine - Anatomy & Physiology|'''BACK TO SMALL INTESTINE - ANATOMY AND PHYSIOLOGY]]</center></big>
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==Introduction==
 
==Introduction==
  
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The jejunum continues from the [[Duodenum - Anatomy & Physiology|duodenum]] and leads into the [[Ileum - Anatomy & Physiology|ileum]]. It is the longest part of the small intestine and is highly coiled. It has digestive and absorptive functions.
 
  
 
==Structure==
 
==Structure==
  
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[[Image:jejunumphoto.jpg|thumb|right|250px|Jejunum(Dog) - © RVC 2008]]
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[[Image:jejunumphoto.jpg|thumb|right|150px|Jejunum(Dog) - Copywright RVC 2008]]
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*The jejunum is the longest part of the small intestine.
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*It is highly coiled and occupies the ventral part of the abdominal cavity, filling those parts that are not occupied by other viscera. This produces species variation (see comparative aspects).
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*It is suspended by the mesentry (mesojejunum). This conveys the blood vessels and nerves and houses lymph nodes.
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**The mesentry converges to its root. This is where the cranial mesenteric artery branches off from the aorta.
  
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Jejunum occupies the ventral part of the abdominal cavity, filling those parts that are not occupied by other viscera. This produces species variation (see [[#Species Differences|species differences]]). It lies on the abdominal floor, separated from the parietal [[Peritoneal Cavity - Anatomy & Physiology|peritoneum]] by the greater omentum. It is suspended by the mesentery (mesojejunum). This conveys the blood vessels and nerves and houses lymph nodes. The mesentery converges to its root. This is where the cranial mesenteric artery branches off from the aorta.
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==Function==
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*Has digestive and absorptive functions.
  
 
==Vasculature==
 
==Vasculature==
  
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The cranial mesenteric artery, a branch of the abdominal aorta, supplies blood to the jejunum, [[Ileum - Anatomy & Physiology|ileum]], [[Caecum - Anatomy & Physiology|caecum]], [[Colon - Anatomy & Physiology|ascending colon]] and part of the [[Colon - Anatomy & Physiology|transverse colon]]. It branches greatly within the mesentery of the jejunum. There are many anastomoses within the mesentery, which ensure that the intestine can survive even if a major division of the cranial mesenteric artery is damaged. The cranial mesenteric vein drains blood from the jejunum and enters the portal vein. It is rich in the products of digestion following a meal. The portal vein enters the [[Liver - Anatomy & Physiology|liver]].
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*The cranial mesenteric artery, a branch of the abdominal aorta, supplies blood to the jejunum, ileum, caecum, ascending colon and part of the transverse colon.
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*It branches greatly within the mesenty of the jejunum.
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**There are many anastomoses within the mesentry, which ensure that the intestine can survive even if a major division of the cranial mesenteric is damaged.
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*The cranial mesenteric vein drains blood from the jejunum and enters the portal vein.
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**It is rich in the products of digestion following a meal.
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**The portal vein enters the liver.
  
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==Species Differences==
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==Innervation==
  
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The position of the jejunum is variable between species as it lies in that part of the abdomen not occupied by other viscera.
 
  
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===Canine===
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==Lymphatics==
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The jejunum lies roughly symmetrically about the midline. It contacts the [[Liver - Anatomy & Physiology|liver]], [[Monogastric Stomach - Anatomy & Physiology|stomach]] and [[Spleen - Anatomy & Physiology|spleen]] cranially and [[Urinary Bladder - Anatomy & Physiology|urinary bladder]] ventrally.
 
  
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===Equine===
 
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The jejunum is confined to the left dorsal part of the abdomen. It is restricted to this position by the large [[Caecum - Anatomy & Physiology|caecum]] on the right, and ascending [[Colon - Anatomy & Physiology|colon]] ventrally on both sides.
 
  
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===Ruminant===
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==Histology==
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The jejunum is pushed entirely to the right side of the abdomen by the [[Rumen - Anatomy & Physiology|rumen]] which is on the left. Coils of the jejunum usually lie within the supraomental recess; although this can vary between individuals depending on fullness of the [[Rumen - Anatomy & Physiology|rumen]] and size of the [[Uterus - Anatomy & Physiology|uterus]].
 
  
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===Porcine===
 
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The jejunum lies in the caudoventral aspect of the abdominal cavity, mainly to the right of the midline. This is due to the presence of the [[Colon - Anatomy & Physiology|ascending colon]] on the left.
 
  
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==Links==
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==Species Differences==
  
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'''Click here for information on [[Intestines, Small and Large - Pathology|pathology of the Small and Large Intestines]]'''
 
  
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{{Template:Learning
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==Links==
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|flashcards = [[Jejunum - Anatomy & Physiology - Flashcards|Jejunum anatomy]]
 
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|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: Lateral view of the feline thorax and abdomen potcast|Lateral view of the feline thorax and abdomen potcast]]<br>[[Video: Female dog abdomen dissection|Female dog abdomen dissection]]<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]]
 
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|powerpoints = [[Gastrointestinal Tract Histology resource|Histology of the jejunum - see part 1]]
 
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|Vetstream = [https://www.vetstream.com/canis/Content/Disease/dis02601.asp Ileus]
 
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}}
 
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==Webinars==
 
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<rss max="10" highlight="none">https://www.thewebinarvet.com/gastroenterology-and-nutrition/webinars/feed</rss>
 
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[[Category:Small Intestine - Anatomy & Physiology]]
 
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[[Category:A&P Done]]
 

Revision as of 14:53, 10 July 2008

BACK TO ALIMENTARY - ANATOMY & PHYSIOLOGY
BACK TO SMALL INTESTINE - ANATOMY AND PHYSIOLOGY


Introduction

Structure

Jejunum(Dog) - Copywright RVC 2008
  • The jejunum is the longest part of the small intestine.
  • It is highly coiled and occupies the ventral part of the abdominal cavity, filling those parts that are not occupied by other viscera. This produces species variation (see comparative aspects).
  • It is suspended by the mesentry (mesojejunum). This conveys the blood vessels and nerves and houses lymph nodes.
    • The mesentry converges to its root. This is where the cranial mesenteric artery branches off from the aorta.

Function

  • Has digestive and absorptive functions.

Vasculature

  • The cranial mesenteric artery, a branch of the abdominal aorta, supplies blood to the jejunum, ileum, caecum, ascending colon and part of the transverse colon.
  • It branches greatly within the mesenty of the jejunum.
    • There are many anastomoses within the mesentry, which ensure that the intestine can survive even if a major division of the cranial mesenteric is damaged.
  • The cranial mesenteric vein drains blood from the jejunum and enters the portal vein.
    • It is rich in the products of digestion following a meal.
    • The portal vein enters the liver.

Innervation

Lymphatics

Histology

Species Differences

Links

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