Difference between revisions of "Gizzard - Anatomy & Physiology"

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<big><center>[[Avian Digestive Tract - Anatomy & Physiology|'''BACK TO THE AVIAN DIGESTIVE TRACT - ANATOMY & PHYSIOLOGY''']]</center></big>
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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 '''[[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 [[The Proventriculus - Anatomy & Physiology|proventriculus]] and to the [[Duodenum - Anatomy & Physiology|duodenum]].
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==Structure and Function==
 
==Structure and Function==
  
[[Image:Gizzard Anatomy.jpg|thumb|right|250px|Gizzard Anatomy - RVC 2008]]
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[[Image:Gizzard Anatomy.jpg|thumb|right|150px|Gizzard Anatomy - RVC 2008]]
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.
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*Mechanical reduction of tougher material through powerful muscular development
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*Cranial to the liver and spleen (contacts the liver)
  
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]].
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*Contacts the sternum and lower left abdominal wall
  
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*Dorsally the abdominal air sacs separate it from the intestines and gonads
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*[[Duodenum - Anatomy & Physiology|Duodenum]] and pancreas lies in its caudal right surface
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*More caudal than the [[The Proventriculus - Anatomy & Physiology|proventriculus]]
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*Roughly on the midline of the bird
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*Lens shaped
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*Interior elongated by cranial and caudal blind sacs
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*Cranial blind sac contacts [[The Proventriculus - Anatomy & Physiology|proventriculus]]
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*Pylorus on right surface next to cranial blind sac
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*Two thick masses of muscle that insert on tendonous surfaces
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*In seed eating birds grit is digested to increase grinding down of food particles
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*Surface covered by glistening tendonous layer
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*The cranial and caudal extremities are formed by powerful red muscular tissue
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*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]]
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[[Image:Gizzard Histology.jpg|thumb|right|150px|Gizzard Histology- Dr. Thomas Caceci]]
 
==Histology==
 
==Histology==
[[Image:Gizzard Histology.jpg|thumb|right|250px|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.
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*Thin, but tough mucous membrane
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*Pale, thin lining raised into ridges
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*3 layers of lamina muscularis
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*Cuboidal epithelium
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*Tubular glands
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*Cuticle of koilin a carbohydrate complex is present due to the solidifying of the glandular secretion. It is replenished as it is worn down.
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*Thick keratin layer to protect muscle
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==Species Differences==
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==Species Diffences==
  
There is no gizzard in '''falconiformes''' (raptors etc.) or in '''stringiformes''' (owls etc.). There is also no gizzard in '''gulls'''.
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*No gizzard in falconiformes (raptors etc.)  
  
==Other Information==
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*No gizzard in stringiformes (owls etc.)
  
Grit should be provided in a seed eating birds diet. It is radiodense and marks out where the gizzard is located on radiographs.
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*No gizzard in gulls
  
{{Template:Learning
 
|flashcards = [[The Avian Alimentary Tract - Anatomy & Physiology - Flashcards|Avian Alimentary Tract]]
 
|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]
 
}}
 
  
==Webinars==
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==Other Information==
<rss max="10" highlight="none">https://www.thewebinarvet.com/gastroenterology-and-nutrition/webinars/feed</rss>
 
  
[[Category:Avian Alimentary System - Anatomy & Physiology]]
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*Grit should be provided in seed eating birds diet. It is radiodense and marks out where the gizzard is located on radiographs.
[[Category:A&P Done]]
 

Revision as of 13:35, 16 July 2008

BACK TO THE AVIAN DIGESTIVE TRACT - ANATOMY & PHYSIOLOGY

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
  • Mechanical reduction of tougher material through powerful muscular development
  • Cranial to the liver and spleen (contacts the liver)
  • Contacts the sternum and lower left abdominal wall
  • Dorsally the abdominal air sacs separate it from the intestines and gonads
  • Duodenum and pancreas lies in its caudal right surface
  • Roughly on the midline of the bird
  • Lens shaped
  • Interior elongated by cranial and caudal blind sacs
  • 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
Gizzard Histology- Dr. Thomas Caceci

Histology

  • Thin, but tough mucous membrane
  • Pale, thin lining raised into ridges
  • 3 layers of lamina muscularis
  • Cuboidal epithelium
  • Tubular glands
  • Cuticle of koilin a carbohydrate complex is present due to the solidifying of the glandular secretion. It is replenished as it is worn down.
  • Thick keratin layer to protect muscle


Species Diffences

  • No gizzard in falconiformes (raptors etc.)
  • No gizzard in stringiformes (owls etc.)
  • No gizzard in gulls


Other Information

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