Difference between revisions of "Reticulum - Anatomy & Physiology"

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==Introduction==
 
==Introduction==
  
The reticulum is the second chamber of the ruminant stomach. It has regular contractions which precede the biphasic ruminal contraction for digestion of food particles.
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The reticulum is the second chamber of the ruminant stomach. It has regular contractions which precede the biphasic ruminal contraction for digestion of food particles. Mechanical digestion and microbial fermentation occur to breakdown food particles for absorption. [[Volatile Fatty Acids|Volatile fatty acids]] are the major product of ruminant digestion.
 
 
Mechanical digestion and microbial fermentation occur to breakdown food particles for absorption. [[Volatile Fatty Acids|Volatile fatty acids]] are the major product of ruminant digestion.
 
 
 
  
 
==Structure==
 
==Structure==
  
[[Image:Reticulum Anatomy Sheep.jpg|thumb|right|150px|Reticulum Anatomy (Sheep) - Copyright RVC 2008]]
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[[Image:Reticulum Anatomy Sheep.jpg|thumb|right|250px|Reticulum Anatomy (Sheep) - Copyright RVC 2008]]
*Covered by greater omentum
 
 
 
*The rumino-reticular fold often gets object lodged. When the [[Rumen - Anatomy & Physiology|rumen]] contracts, the object can be pushed through the reticulum wall into the [[Structure of the Heart - Anatomy & Physiology#Pericardium|pericardium]] and [[Heart - Anatomy & Physiology|heart]].
 
 
 
*Opening at the cardia into both the reticulum and the [[Rumen - Anatomy & Physiology|rumen]] is called the reticuluar groove (see [[Oesophageal Groove|oseophageal groove]]). The reticular groove also opens into the [[Omasum - Anatomy & Physiology|omasum]].
 
 
 
*Cranial to the [[Rumen - Anatomy & Physiology|rumen]]
 
 
 
*Ribs 6-8
 
  
*From cardia to the diaphragm
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The reticulum is covered by greater omentum. The rumino-reticular fold often gets objects lodged. When the [[Rumen - Anatomy & Physiology|rumen]] contracts, the object can be pushed through the reticulum wall into the [[Heart Structure - Anatomy & Physiology#Pericardium|pericardium]] and [[Heart - Anatomy & Physiology|heart]].
  
*Lies above the xiphoid process of the sternum
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Opening at the cardia into both the reticulum and the [[Rumen - Anatomy & Physiology|rumen]] is called the reticular groove (see [[Oesophageal Groove|oseophageal groove]]). The reticular groove also opens into the [[Omasum - Anatomy & Physiology|omasum]].
  
*Serosa covers the surface
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The reticulum is cranial to the [[Rumen - Anatomy & Physiology|rumen]] at ribs 6-8. It is located from cardia to the diaphragm. It lies above the xiphoid process of the sternum. Serosa covers the surface.
  
 
==Function==
 
==Function==
  
*Waste removal
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The functions of the reticulum include waste removal and movement. Simpler products of digestion are assimilated directly, others continue down the digestive tract for further digestion.
  
*Movement
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See [[Rumination|rumination]] and [[Eructation|eructation]].
 
 
*Simpler products of digestion are assilimated directly, others continue down the digestive tract for further digestion
 
 
 
*See [[Rumination - Anatomy & Physiology|rumination]]
 
 
 
*See [[Eructation - Anatomy & Physiology|eructation]]
 
  
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==Ruminoreticular contraction==
  
==Ruminoreticular contraction==
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[[Image:Contractions of the ruminoreticulum diagram.jpg|thumb|right|250px|Diagram of the contractions of the ruminoreticulum - Copyright RVC 2008]]
  
[[Image:Contractions of the ruminoreticulum diagram.jpg|thumb|right|150px|Diagram of the contractions of the ruminoreticulum - Copyright RVC 2008]]
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The contractions have two main functions:
*Primary mixes food
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:Primary contraction mixes food by a ruminoreticuluar mixing cycle. There are 2 contractions of the reticulum (2nd most powerful) which continue over the [[Rumen - Anatomy & Physiology|rumen]]. Ingesta flows from the reticulum to cranial rumenal sac and then to reticulum (or ventral sac). It occurs every 60 seconds.
**Mixing cycle of ruminoreticulum
 
**2 contractions of the reticulum (2nd most powerful) which continues over the [[Rumen - Anatomy & Physiology|rumen]]
 
**Ingesta flows from the reticulum to cranial ruminal sac to reticulum (or ventral sac)
 
**Every 60 seconds
 
  
*Secondary lets gas out
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:The secondary contraction lets gas out (see [[Eructation|eructation]]). Ingesta flows from the ventral blind sac to the dorsal blind sac then to dorsal sac (eructation) and to the ventral sac.
**See [[Eructation - Anatomy & Physiology|eructation]]
 
**Ingesta flows from ventral blind sac to dorsal blind sac to dorsal sac ([[Eructation - Anatomy & Physiology|eructation]]) to ventral sac
 
  
 
==Vasculature==
 
==Vasculature==
  
*Cranial mesenteric artery
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The reticulum receives blood supply from the '''cranial mesenteric artery''', '''celiac artery''' and '''right and left ruminal arteries'''.
 
 
*Celiac artery
 
 
 
*Right and left ruminal arteries
 
 
 
  
 
==Innervation==
 
==Innervation==
  
*Dorsal vagus ([[Cranial Nerves - Anatomy & Physiology|CN X]]) (most important)
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The reticulum is innervated by the '''dorsal vagus''' ([[Cranial Nerves - Anatomy & Physiology|CN X]]) (most important) and the '''ventral vagus''' nerve ([[Cranial Nerves - Anatomy & Physiology|CN X]]).
  
*Ventral vagus ([[Cranial Nerves - Anatomy & Physiology|CN X]])
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==Lymphatics==
  
==Lymphatics==
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Numerous small lymph nodes are scattered in the grooves. The lymph drains to larger atrial nodes between the cardia and [[Omasum - Anatomy & Physiology|omasum]], then to the cistera chyli.
  
*Numerous small lymph nodes are scattered in the grooves
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==Histology==
  
*The lymph drains to larger atrial nodes between the cardia and [[Omasum - Anatomy & Physiology|omasum]], then to the cistera chyli
+
[[Image:Reticulum Histology Sheep.jpg|thumb|right|250px|Reticulum Histology (Sheep) - Copyright RVC 2008]]
 +
The reticulum is lined by a '''keratinised stratified squamous epithelium''' and there are no glands present. The characteristic honeycomb appearance is formed by the mucosal layer trown into short and tall folds. The folds gradually merge into '''papillae''', where the reticulum meets the rumen. [[Tongue - Anatomy & Physiology#Types of Papillae|Conical papillae]], also called secondary papillae, are present on folds, providing a rough surface to increase food breakdown.
  
  
==[[Reticulum - Histology|Histology]]==
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The '''lamina muscularis''' is present as discrete bands of smooth muscle (not continuous). There are two thick layers of '''tunica muscularis''', the inner circular and the outer longitudinal. The upper keratinised layer of the reticulum protects against abrasion and the deeper layers metabolise [[Volatile Fatty Acids|volatile fatty acids]].
  
 
==Species Differences==
 
==Species Differences==
  
 
===Small Ruminants===
 
===Small Ruminants===
*Larger reticulum compared to cattle
 
  
*In sheep and goats the ridges of the reticular cells are lower and have more prominant serrated edges than in cattle
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Small ruminants have a larger reticulum compared to cattle. In sheep and goats, the ridges of the reticular cells are lower and have more prominent serrated edges than in cattle. The papillated ruminal mucosa expands over a greater proportion of the reticulum.
 
 
*The papillated ruminal mucosa expands over a greater proportion of the reticulum
 
 
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==Test yourself with the Stomachs of the Ruminant flashcards==
 
 
[[The_Stomachs_of_the_Ruminant_-_Anatomy_%26_Physiology_-_Flashcards#The_Reticulum|Reticulum Flashcards]]
 
  
 
==Links==
 
==Links==
  
[[Rumen - Anatomy & Physiology|The Rumen - Anatomy & Physiology]]
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'''Click here for information on [[Rumen - Anatomy & Physiology|Rumen]]'''
 
 
[[Omasum - Anatomy & Physiology|The Omasum - Anatomy & Physiology]]
 
 
 
[[Abomasum - Anatomy & Physiology|The Abomasum- Anatomy & Physiology]]
 
 
 
'''Video'''
 
 
 
[http://stream2.rvc.ac.uk/Anatomy/bovine/Pot0052.mp4 Pot 52 Lateral view of the Abdomen of a young Ruminant]
 
 
 
[http://stream2.rvc.ac.uk/Anatomy/bovine/pot0175.mp4 Pot 175 Sections of the Ruminant Stomach]
 
 
 
[http://stream2.rvc.ac.uk/Frean/sheep/LeftSideTopography.mp4 Left sided topography of the Ovine Abdomen and Thorax]
 
  
[http://stream2.rvc.ac.uk/Frean/sheep/RightSideTopography.mp4 Right sided topography of the Ovine Abdomen]
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'''Click here for information on [[Omasum - Anatomy & Physiology|Omasum]]'''
  
[http://stream2.rvc.ac.uk/Frean/sheep/RuminantStomachStructure.mp4 Structure of the ruminant forestomachs]
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'''Click here for information on [[Abomasum - Anatomy & Physiology|Abomasum]]'''
  
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{{Template:Learning
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|flashcards = [[Reticulum Flashcards]]
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<!-----|videos = [[Video: Sections of the interior of the complex ruminant stomach potcast|Sections of the interior of the complex ruminant stomach potcast]]<br>[[Video: Ruminant forestomach structure dissection|Ruminant forestomach structure dissection]]<br>[[Video: Bovine reticular groove potcast|Bovine reticular groove potcast]]<br>[[Video: Ruminant abdomen potcast|Ruminant abdomen potcast]]<br>[[Video: Ovine left-sided abdominal and thoracic dissection|Ovine left-sided abdominal and thoracic dissection]]<br>[[Video: Ovine right-sided abdominal and thoracic dissection| Ovine right-sided abdominal and thoracic dissection]]--->}}
  
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==Webinars==
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<rss max="10" highlight="none">https://www.thewebinarvet.com/gastroenterology-and-nutrition/webinars/feed</rss>
 +
<rss max="10" highlight="none">https://www.thewebinarvet.com/surgery/webinars/feed</rss>
  
 
[[Category:Stomach - Anatomy & Physiology]]
 
[[Category:Stomach - Anatomy & Physiology]]
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[[Category:A&P Done]]
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[[Category:Alimentary Anatomy - Cattle]]

Latest revision as of 19:45, 27 October 2022


Introduction

The reticulum is the second chamber of the ruminant stomach. It has regular contractions which precede the biphasic ruminal contraction for digestion of food particles. Mechanical digestion and microbial fermentation occur to breakdown food particles for absorption. Volatile fatty acids are the major product of ruminant digestion.

Structure

Reticulum Anatomy (Sheep) - Copyright RVC 2008

The reticulum is covered by greater omentum. The rumino-reticular fold often gets objects lodged. When the rumen contracts, the object can be pushed through the reticulum wall into the pericardium and heart.

Opening at the cardia into both the reticulum and the rumen is called the reticular groove (see oseophageal groove). The reticular groove also opens into the omasum.

The reticulum is cranial to the rumen at ribs 6-8. It is located from cardia to the diaphragm. It lies above the xiphoid process of the sternum. Serosa covers the surface.

Function

The functions of the reticulum include waste removal and movement. Simpler products of digestion are assimilated directly, others continue down the digestive tract for further digestion.

See rumination and eructation.

Ruminoreticular contraction

Diagram of the contractions of the ruminoreticulum - Copyright RVC 2008

The contractions have two main functions:

Primary contraction mixes food by a ruminoreticuluar mixing cycle. There are 2 contractions of the reticulum (2nd most powerful) which continue over the rumen. Ingesta flows from the reticulum to cranial rumenal sac and then to reticulum (or ventral sac). It occurs every 60 seconds.
The secondary contraction lets gas out (see eructation). Ingesta flows from the ventral blind sac to the dorsal blind sac then to dorsal sac (eructation) and to the ventral sac.

Vasculature

The reticulum receives blood supply from the cranial mesenteric artery, celiac artery and right and left ruminal arteries.

Innervation

The reticulum is innervated by the dorsal vagus (CN X) (most important) and the ventral vagus nerve (CN X).

Lymphatics

Numerous small lymph nodes are scattered in the grooves. The lymph drains to larger atrial nodes between the cardia and omasum, then to the cistera chyli.

Histology

Reticulum Histology (Sheep) - Copyright RVC 2008

The reticulum is lined by a keratinised stratified squamous epithelium and there are no glands present. The characteristic honeycomb appearance is formed by the mucosal layer trown into short and tall folds. The folds gradually merge into papillae, where the reticulum meets the rumen. Conical papillae, also called secondary papillae, are present on folds, providing a rough surface to increase food breakdown.


The lamina muscularis is present as discrete bands of smooth muscle (not continuous). There are two thick layers of tunica muscularis, the inner circular and the outer longitudinal. The upper keratinised layer of the reticulum protects against abrasion and the deeper layers metabolise volatile fatty acids.

Species Differences

Small Ruminants

Small ruminants have a larger reticulum compared to cattle. In sheep and goats, the ridges of the reticular cells are lower and have more prominent serrated edges than in cattle. The papillated ruminal mucosa expands over a greater proportion of the reticulum.

Links

Click here for information on Rumen

Click here for information on Omasum

Click here for information on Abomasum


Reticulum - Anatomy & Physiology Learning Resources
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Flashcards
Test your knowledge using flashcard type questions
Reticulum Flashcards


Webinars

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