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==Introduction==

==Introduction==

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]].

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]].

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]].

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]].

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.

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==

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

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 - Anatomy & Physiology|rumination]] and [[Eructation - Anatomy & Physiology|eructation]].

See [[Rumination|rumination]] and [[Eructation|eructation]].

==Ruminoreticular contraction==

==Ruminoreticular contraction==

[[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|250px|Diagram of the contractions of the ruminoreticulum - Copyright RVC 2008]]

The contractions primary mix food. There is a mixing cycle of ruminoreticulum. There are 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). It occurs every 60 seconds. The secondary contraction lets gas out. (See [[Eructation - Anatomy & Physiology|eructation]]). Ingesta flows from the ventral blind sac to the dorsal blind sac to dorsal sac ([[Eructation - Anatomy & Physiology|eructation]]) to the ventral sac.

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 - Anatomy & Physiology|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|eructation]]). Ingesta flows from the ventral blind sac to the dorsal blind sac then to dorsal sac (eructation) and to the ventral sac.

==Vasculature==

==Vasculature==

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

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

==Innervation==

==Innervation==

==Histology==

==Histology==

[[Image:Reticulum Histology Sheep.jpg|thumb|right|150px|Reticulum Histology (Sheep) - Copyright RVC 2008]]

[[Image:Reticulum Histology Sheep.jpg|thumb|right|250px|Reticulum Histology (Sheep) - Copyright RVC 2008]]

The reticulum has a '''keratinised stratified squamous epithelium''' and no present glands. The reticulum has a honeycomb appearance of short and tall folds, as the mucosal layer is thrown into 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.

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.

The '''lamina muscularis''' is present as discrete bands of smooth muscle (not continuous). There are 2 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]].

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===

Small ruminants have a 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.

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.

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==Links==

==Links==

'''Click here for information on [[Rumen - Anatomy & Physiology|Rumen]]'''

 

'''Click here for information on [[Rumen - Anatomy & Physiology|rumen - Anatomy & Physiology]]'''

 

'''Click here for information on [[Omasum - Anatomy & Physiology|omasum - Anatomy & Physiology]]'''

 

 

 

 

 

[http://stream2.rvc.ac.uk/Frean/sheep/RightSideTopography.mp4 Right sided topography of the Ovine Abdomen]

'''Click here for information on [[Omasum - Anatomy & Physiology|Omasum]]'''

[http://stream2.rvc.ac.uk/Frean/sheep/RuminantStomachStructure.mp4 Structure of the ruminant forestomachs]

'''Click here for information on [[Abomasum - Anatomy & Physiology|Abomasum]]'''

[[Category:Stomach - Anatomy & Physiology]]

[[Category:Stomach - Anatomy & Physiology]]

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[[Category:Alimentary Anatomy - Cattle]]