Changes

==Introduction==

==Introduction==

==Structure==

==Structure==

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

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

The omasum is right of the midline. The [[Rumen - Anatomy & Physiology|Rumen]] and [[Reticulum - Anatomy & Physiology|reticulum]] are located to the left and the liver and body wall to the right. The omasum is covered by lesser omentum and is bilaterally flattened. It is located at ribs 8-11. The lower pole has an extensive connection to the fundic region of the [[Abomasum - Anatomy & Physiology|abomasum]]. An '''omasal canal''' is present known as the '''omasal groove'''. The floor is smooth except for low ridges and projections around the upper opening. The opening to the [[Reticulum - Anatomy & Physiology|reticulum]] is at the cranial end and the opening to the [[Abomasum - Anatomy & Physiology|abomasum]] is at the caudal end of the omasal canal. The exit to the abomasum is a large oval opening, partly covered by overhanging abomasal folds.

The omasum is right of the midline. The [[Rumen - Anatomy & Physiology|Rumen]] and [[Reticulum - Anatomy & Physiology|reticulum]] are located to the left and the liver and body wall to the right. The omasum is covered by lesser omentum and is bilaterally flattened. It is located at ribs 8-11. The lower pole has an extensive connection to the fundic region of the [[Abomasum - Anatomy & Physiology|abomasum]]. The '''omasal canal''' is formed between the end of the '''laminae''' and the '''omasal groove''', part of the '''gastric groove''' between the cardia and the pyloric sphincter. The omasal canal passes between the [[Reticulum - Anatomy & Physiology|reticulum]] and the [[Abomasum - Anatomy & Physiology|abomasum]].  Its mucosa is smooth except for particularly large papillae around the reticulo-omasal opening. The omaso-abomasal opening is a large and oval, partly covered by overhanging abomasal folds.

==Function==

==Function==

A function of the omasum is absorption. Food enters omasum at second biphasic reticular contraction. The omasum itself has biphasic contractions. The first contraction expels fluid by squeezing the ingesta from the omasal canal between the lamellae. The second contraction expels solids by mass contraction of the omasum. Contractions are slower than the rumenoreticular contractions (see [[Rumination - Anatomy & Physiology|rumination]]). Food is squeezed between lamellae.  

A function of the omasum is absorption. Food enters omasum at second biphasic reticular contraction. The omasum itself has biphasic contractions. The first contraction expels fluid by squeezing the ingesta from the omasal canal between the lamellae. The second contraction expels solids by mass contraction of the omasum. Contractions are slower than the rumenoreticular contractions (see [[Rumination|rumination]]). Food is squeezed between lamellae.  

==Vasculature==

==Vasculature==

The blood supply to the omasum includes the '''cranial mesenteric artery''', the '''caudal mesenteric artery''' and the '''left gastric''' and '''left gastroepiploic arteries'''.

The blood supply to the omasum includes the '''cranial mesenteric artery''', the '''left gastric''' and the '''left gastroepiploic arteries'''.

==Innervation==

==Innervation==

{{Template:Learning

{{Template:Learning

|flashcards = [[The Stomachs of the Ruminant - Anatomy & Physiology - Flashcards#The Omasum|Omasum flashcards]]

|flashcards = [[Omasum Flashcards]]

|videos = [http://stream2.rvc.ac.uk/Anatomy/bovine/Pot0052.mp4 Lateral view of the Abdomen of a young Ruminant]<br>[http://stream2.rvc.ac.uk/Anatomy/bovine/pot0175.mp4 Sections of the Ruminant Stomach]<br>[http://stream2.rvc.ac.uk/Anatomy/ovine/Pot0047.mp4 Ovine Omasum and Abomasum]<br>[http://stream2.rvc.ac.uk/Frean/sheep/LeftSideTopography.mp4 Left sided topography of the Ovine Abdomen and Thorax]<br>[http://stream2.rvc.ac.uk/Frean/sheep/RightSideTopography.mp4 Right sided topography of the Ovine Abdomen]<br>[http://stream2.rvc.ac.uk/Frean/sheep/RuminantStomachStructure.mp4 Structure of the ruminant forestomachs]

|videos = [[Video: Bovine omasum potcast|Bovine omasum potcast]]<br>[[Video: Ovine omasum and abomasum potcast|Ovine omasum and abomasum potcast]]<br>[[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]]

|powerpoints = [[Ruminant Gastrointestinal Tract Histology resource|Histology of the ruminant gastrointestinal tract]]  

}}

}}

 

[[Category:Stomach - Anatomy & Physiology]]

[[Category:Stomach - Anatomy & Physiology]]

[[Category:A&P Done]]

[[Category:A&P Done]]