Difference between revisions of "Gizzard - Anatomy & Physiology"

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==Introduction==
 
==Introduction==
  
The gizzard is also referred to as the muscular stomach or ventriculus. It is connected by the isthmus to the [[The Proventriculus - Anatomy & Physiology|proventriculus]] and to the [[Duodenum - Anatomy & Physiology|duodenum]].
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The gizzard is also referred to as the muscular stomach or '''ventriculus'''. It is connected by the '''isthmus''' to the '''[[Proventriculus - Anatomy & Physiology|proventriculus]]''' and to the '''[[Duodenum - Anatomy & Physiology|duodenum]]'''.
  
 
==Structure and Function==
 
==Structure and Function==
  
[[Image:Gizzard Anatomy.jpg|thumb|right|150px|Gizzard Anatomy - RVC 2008]]
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[[Image:Gizzard Anatomy.jpg|thumb|right|250px|Gizzard Anatomy - RVC 2008]]
*Mechanical reduction of tougher material through powerful muscular development
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The gizzard allows mechanical reduction of tougher material through powerful muscular development. It is cranial to the [[Avian Liver - Anatomy & Physiology|liver]] and [[Spleen - Anatomy & Physiology|spleen]]. It contacts the sternum and lower left abdominal wall as well as the [[Avian Liver - Anatomy & Physiology|liver]]. Dorsally the abdominal air sacs separate it from the intestines and gonads. The [[Duodenum - Anatomy & Physiology|duodenum]] and [[Pancreas - Anatomy & Physiology|pancreas]] lie at its caudal right surface. It is more caudal than the [[Proventriculus - Anatomy & Physiology|proventriculus]] and is roughly on the midline of the bird. It is lens shaped and the interior is elongated by the cranial and caudal blind sacs. The cranial blind sac contacts the [[Proventriculus - Anatomy & Physiology|proventriculus]]. The pylorus is on right surface next to the cranial blind sac.
  
*Cranial to the [[Avian Liver - Anatomy & Physiology|liver]] and [[Spleen - Anatomy & Physiology|spleen]] (contacts the [[Avian Liver - Anatomy & Physiology|liver]])
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The gizzard consists of two thick masses of muscle that insert on tendonous surfaces. In seed eating birds, grit is digested to increase the grinding down of food particles. Its surface is covered by a glistening tendonous layer. The cranial and caudal extremities are formed by a powerful red muscular tissue. A circular '''aponeurosis''' is present, connecting the cranial end of the gizzard to the isthmus and the caudal end to the [[Duodenum - Anatomy & Physiology|duodenum]]. It appears yellow due to bile reflux from the [[Duodenum - Anatomy & Physiology|duodenum]]. When the thin muscles of the gizzard contract, food passes from the gizzard into the [[Duodenum - Anatomy & Physiology|duodenum]], when the thick muscles of the gizzard contract, food moves back into the [[Proventriculus - Anatomy & Physiology|proventriculus]].
  
*Contacts the sternum and lower left abdominal wall
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==Histology==
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[[Image:Gizzard Histology.jpg|thumb|right|250px|Gizzard Histology- Dr. Thomas Caceci]]
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The gizzard has a thin, but tough '''mucous membrane'''. It has a pale, thin lining raised into ridges with three layers of '''lamina muscularis'''. The gizzard also has cuboidal epithelium and some tubular glands present. There is a thick keratin layer to protect the muscle.
  
*Dorsally the abdominal air sacs separate it from the intestines and gonads
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The '''cuticle of koilin''' is a carbohydrate complex, present due to the solidifying of the glandular secretion. It is replenished as it is worn down.
 
 
*[[Duodenum - Anatomy & Physiology|Duodenum]] and [[Pancreas - Anatomy & Physiology|pancreas]] lies in its caudal right surface
 
 
 
*More caudal than the [[The Proventriculus - Anatomy & Physiology|proventriculus]]
 
 
 
*Roughly on the midline of the bird
 
 
 
*Lens shaped
 
 
 
*Interior elongated by cranial and caudal blind sacs
 
 
 
*Cranial blind sac contacts [[The Proventriculus - Anatomy & Physiology|proventriculus]]
 
 
 
*Pylorus on right surface next to cranial blind sac
 
 
 
*Two thick masses of muscle that insert on tendonous surfaces
 
 
 
*In seed eating birds grit is digested to increase grinding down of food particles
 
 
 
*Surface covered by glistening tendonous layer
 
 
 
*The cranial and caudal extremities are formed by powerful red muscular tissue
 
 
 
*A circular aponeurosis is present connecting the cranial end of the gizzard to the isthmus and the caudal end to the [[Duodenum - Anatomy & Physiology|duodenum]]
 
 
 
*Appears yellow due to bile reflux from the [[Duodenum - Anatomy & Physiology|duodenum]]
 
 
 
*When the thin muscles of the gizzard contract, food passes from the gizzard into the [[Duodenum - Anatomy & Physiology|duodenum]]
 
 
 
*When the thick muscles of the gizzard contract, food moves back into the [[The Proventriculus - Anatomy & Physiology|proventriculus]]
 
 
 
[[Image:Gizzard Histology.jpg|thumb|right|150px|Gizzard Histology- Dr. Thomas Caceci]]
 
 
 
==[[Gizzard - Histology|Histology]]==
 
  
 
==Species Differences==
 
==Species Differences==
  
*No gizzard in falconiformes (raptors etc.)  
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There is no gizzard in '''falconiformes''' (raptors etc.) or in '''stringiformes''' (owls etc.). There is also no gizzard in '''gulls'''.
 
 
*No gizzard in stringiformes (owls etc.)
 
 
 
*No gizzard in gulls
 
  
 
==Other Information==
 
==Other Information==
  
*Grit should be provided in seed eating birds diet. It is radiodense and marks out where the gizzard is located on radiographs.
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Grit should be provided in a seed eating birds diet. It is radiodense and marks out where the gizzard is located on radiographs.
 
 
==Test yourself with the Avian Alimentary Tract flashcards==
 
 
 
[[The Avian Alimentary Tract - Anatomy & Physiology - Flashcards|Avian Alimentary Tract Flashcards]]
 
  
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{{Template:Learning
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|flashcards = [[The Avian Alimentary Tract - Anatomy & Physiology - Flashcards|Avian Alimentary Tract]]
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|OVAM = [http://www.onlineveterinaryanatomy.net/content/interactive-avian-anatomy-digestive-system-4 Avian Interactive Anatomy - Gizzard 1]<br>[http://www.onlineveterinaryanatomy.net/content/interactive-avian-anatomy-digestive-system-3 Avian Interactive Anatomy - Gizzard 2]
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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>
  
 
[[Category:Avian Alimentary System - Anatomy & Physiology]]
 
[[Category:Avian Alimentary System - Anatomy & Physiology]]
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[[Category:A&P Done]]

Latest revision as of 21:19, 28 November 2022


Introduction

The gizzard is also referred to as the muscular stomach or ventriculus. It is connected by the isthmus to the proventriculus and to the duodenum.

Structure and Function

Gizzard Anatomy - RVC 2008

The gizzard allows mechanical reduction of tougher material through powerful muscular development. It is cranial to the liver and spleen. It contacts the sternum and lower left abdominal wall as well as the liver. Dorsally the abdominal air sacs separate it from the intestines and gonads. The duodenum and pancreas lie at its caudal right surface. It is more caudal than the proventriculus and is roughly on the midline of the bird. It is lens shaped and the interior is elongated by the cranial and caudal blind sacs. The cranial blind sac contacts the proventriculus. The pylorus is on right surface next to the cranial blind sac.

The gizzard consists of two thick masses of muscle that insert on tendonous surfaces. In seed eating birds, grit is digested to increase the grinding down of food particles. Its surface is covered by a glistening tendonous layer. The cranial and caudal extremities are formed by a powerful red muscular tissue. A circular aponeurosis is present, connecting the cranial end of the gizzard to the isthmus and the caudal end to the duodenum. It appears yellow due to bile reflux from the duodenum. When the thin muscles of the gizzard contract, food passes from the gizzard into the duodenum, when the thick muscles of the gizzard contract, food moves back into the proventriculus.

Histology

Gizzard Histology- Dr. Thomas Caceci

The gizzard has a thin, but tough mucous membrane. It has a pale, thin lining raised into ridges with three layers of lamina muscularis. The gizzard also has cuboidal epithelium and some tubular glands present. There is a thick keratin layer to protect the muscle.

The cuticle of koilin is a carbohydrate complex, present due to the solidifying of the glandular secretion. It is replenished as it is worn down.

Species Differences

There is no gizzard in falconiformes (raptors etc.) or in stringiformes (owls etc.). There is also no gizzard in gulls.

Other Information

Grit should be provided in a seed eating birds diet. It is radiodense and marks out where the gizzard is located on radiographs.


Gizzard - Anatomy & Physiology Learning Resources
FlashcardsFlashcards logo.png
Flashcards
Test your knowledge using flashcard type questions
Avian Alimentary Tract
OVAMOVAM-no text.png
OVAM
Anatomy Museum Resources
Avian Interactive Anatomy - Gizzard 1
Avian Interactive Anatomy - Gizzard 2


Webinars

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