WikiVet English

Changes

Reticulum - Anatomy & Physiology (view source)

Revision as of 23:21, 25 August 2008

4,705 bytes added ,  23:21, 25 August 2008
no edit summary
Line 9: Line 9:  
}}
 
}}
 
<br>
 
<br>
 +
==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 - Anatomy & Physioogy|Volatile fatty acids]] are the major product of ruminant digestion.
 +
 +
 +
==Structure==
 +
 +
[[Image:Reticulum Anatomy Sheep.jpg|thumb|right|150px|Reticulum Anatomy (Sheep) - Copyright RVC 2008]]
 +
*Covered by greater omentum
 +
 +
*The rumino-reticular fold often gets object lodged. When the [[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 [[The Rumen - Anatomy & Physiology|rumen]] is called the reticuluar groove (see [[Oesophageal groove|oseophageal groove]]). The reticular groove also opens into the [[The Omasum|omasum]].
 +
 +
*Cranial to the [[The Rumen - Anatomy & Physiology|rumen]]
 +
 +
*Ribs 6-8
 +
 +
*From cardia to the diaphragm
 +
 +
*Lies above the xiphoid process of the sternum
 +
 +
*Serosa covers the surface
 +
 +
==Function==
 +
 +
*Waste removal
 +
 +
*Movement
 +
 +
*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]]
 +
 +
 +
==Ruminoreticular contraction==
 +
 +
[[Image:Contractions of the ruminoreticulum diagram.jpg|thumb|right|150px|Diagram of the contractions of the ruminoreticulum - Copyright RVC 2008]]
 +
*Primary mixes food
 +
**Mixing cycle of ruminoreticulum
 +
**2 contractions of the reticulum (2nd most powerful) which continues over the [[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
 +
**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==
 +
 +
*Cranial mesenteric artery
 +
 +
*Celiac artery
 +
 +
*Right and left ruminal arteries
 +
 +
 +
==Innervation==
 +
 +
*Dorsal vagus ([[Nervous System - CNS - Anatomy & Physiology#Innervation - Cranial Nerves|CN X]]) (most important)
 +
 +
*Ventral vagus ([[Nervous System - CNS - Anatomy & Physiology#Innervation - Cranial Nerves|CN X]])
 +
 +
==Lymphatics==
 +
 +
*Numerous small lymph nodes are scattered in the grooves
 +
 +
*The lymph drains to larger atrial nodes between the cardia and [[The Omasum|omasum]], then to the cistera chyli
 +
 +
 +
==Histology==
 +
 +
[[Image:Reticulum Histology Sheep.jpg|thumb|right|150px|Reticulum Histology (Sheep) - Copyright RVC 2008]]
 +
*Keratinised stratified squamous epithelium
 +
 +
*No glands
 +
 +
*Honeycomb appearance of short and tall folds
 +
 +
*Mucosal layer thrown into folds
 +
 +
*The folds gradually merge into papillae where the reticulum meets the rumen
 +
 +
*Lamina muscularis present as discrete bands of smooth muscle (not continuous)
 +
 +
*[[Oral Cavity - Tongue - Anatomy & Physiology#Types of Papillae|Conical papillae]], also called secondary papillae, on folds providing a rough surface to increase food breakdown
 +
 +
*2 thick layers of tunica muscularis- inner circular and outer longitudinal
 +
 +
*The upper keratinised layer protects against abrasion
 +
 +
*The deeper layers metabolise [[Volatile Fatty Acids - Anatomy & Physioogy|volatile fatty acids]]
 +
 +
 +
==Species Differences==
 +
 +
===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
 +
 +
*The papillated ruminal mucosa expands over a greater proportion of the reticulum
 +
 +
==Links==
 +
 +
[[The Rumen - Anatomy & Physiology|The Rumen - Anatomy & Physiology]]
 +
 +
[[The Omasum|The Omasum - Anatomy & Physiology]]
 +
 +
[[The Abomasum|The Abomasum- Anatomy & Physiology]]
 +
 +
[[The Stomachs of the Ruminant - Anatomy & Physiology - Flashcards#The Reticulum|The Reticulum Flashcards]]
 +
 +
'''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]
 +
 +
[http://stream2.rvc.ac.uk/Frean/sheep/RuminantStomachStructure.mp4 Structure of the ruminant forestomachs]
Retrieved from "https://en.wikivet.net/Special:MobileDiff/31527"