Difference between revisions of "Oesophagus - Anatomy & Physiology"

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|backcolour =BCED91
 
|linkpage =Alimentary - Anatomy & Physiology
 
|linktext =Alimentary System
 
|maplink = Alimentary (Concept Map)- Anatomy & Physiology
 
|pagetype =Anatomy
 
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<br>
 
 
==Introduction==
 
==Introduction==
  
The oesophagus (or gullet) is a muscular tube which transports food from the [[Pharynx - Anatomy & Physiology|pharynx]] to the [[Forestomach - Anatomy & Physiology|stomach]]. A bolus of food is passed down the oesophagus by [http://en.wikipedia.org/wiki/Peristalsis| peristalsis].
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The oesophagus (or gullet) is a muscular tube which transports food from the [[Pharynx - Anatomy & Physiology|pharynx]] to the [[Monogastric Stomach - Anatomy & Physiology|stomach]]. A bolus of food is passed down the oesophagus by peristalsis. The oesophagus is divided into cervical, thoracic and abdominal sections.
 
 
The oesophagus is divided into cevical, thoracic and abdominal sections.
 
  
 
==Structure and Function==
 
==Structure and Function==
 +
[[Image:Oesophagus anatomy.jpg|thumb|right|250px|Oesophagus Anatomy - Copyright RVC 2008]]
 +
The oesophagus begins dorsal to the '''cricoid cartilage''' of the [[Larynx - Anatomy & Physiology|larynx]]. It follows the trachea down the neck, first on the left and then medially once in thorax in the mediastinum. It passes over the [[Heart - Anatomy & Physiology|heart]] then through the oesophageal hiatus of the diaphragm. It passes over the dorsal border of the [[Liver - Anatomy & Physiology|liver]] then joins the [[Monogastric Stomach - Anatomy & Physiology|stomach]] at the cardia. The cervical section is accompanied by the common carotid artery, the vagosympathetic trunk and the recurrent laryngeal nerves. The thoracic section is accompanied by the right and left vagus nerves ([[Cranial Nerves - Anatomy & Physiology|CN X]]). 
  
[[Image:Oesophagus anatomy.jpg|thumb|right|150px|Oesophagus Anatomy - Copyright RVC 2008]]
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There are different proportions of striated muscle across the species;
*Begins dorsal to cricoid cartilage of [[Larynx - Anatomy & Physiology|larynx]]
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:Dog and ruminant = 100%
 
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:Cat              = 80% (rostral)
*Follows trachea down neck, first on the left and then medially once in thorax in the mediastinum
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:Horse            = 65% (rostral)
 
+
:Pig              = 33% (rostral)
*Passes over [[Heart - Anatomy & Physiology|heart]] then through the oesophageal hiatus of the diaphragm
 
 
 
*Passes over the dorsal border of the [[Liver - Anatomy & Physiology|liver]] then joins the [[Forestomach - Anatomy & Physiology|stomach]] at the cardia
 
 
 
*The cervical section is accompanied by the common carotid artery, the vagosympathetic trunk and the recurrent laryngeal nerves
 
 
 
*The thoracic section is accompanied by the right and left vagus nerves ([[Nervous System - CNS - Anatomy & Physiology#Innervation - Cranial Nerves|CN X]])
 
 
 
*Different proportions of striated muscle across the species
 
**Dog and ruminant = 100%
 
**Cat              = 80% (rostral)
 
**Horse            = 65% (rostral)
 
**Pig              = 33% (rostral)
 
 
 
 
 
  
 
==Histology==
 
==Histology==
 +
[[Image:Oesophagus Histology.jpg|thumb|right|250px|Oesophagus Histology (Rat) - Copyright RVC 2008]]
 +
The oesophagus has a '''stratified squamous epithelium'''. It has mucosal folds present for distension. The degree of keratinisation of the oesophagus depends on the animal's diet.
  
[[Image:Oesophagus Histology.jpg|thumb|right|150px|Oesophagus Histology (Rat) - Copyright RVC 2008]]
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The '''lamina propria''' of the oesophagus contains collagen and elastic fibres that are sparsely distributed. The '''lamina muscularis''' of the oesophagus is smooth or skeletal muscle, depending on the species. The inner circular layer of the '''tunica muscularis''' thickens near the gastric junction, forming a sphincter.
*Stratified squamous epithelium
 
 
 
*Mucosal folds for distension
 
 
 
*Degree of keratinisation depend on diet
 
 
 
*Lamina propria contains collagen and elastic fibres sparsely distributed
 
 
 
*Lamina muscularis is smooth muscle
 
 
 
*No glands in mucosa
 
  
*Mucous glands (tubulo-acinar) present in submucosa
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Whilst there are no glands present in the mucosa, there are mucous glands (tubulo-acinar) present in the submucosa.
  
*Inner circular layer of tunica muscularis thickens near gastric junction forming a sphincter
 
 
[[Image:Oesophagus Structure Diagram.jpg|thumb|right|150px|Oesophagus Structure Diagram - Copyright NOTTINGHAM 2008]]
 
 
==Innervation==
 
==Innervation==
  
*Sympathetic nerves
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The oesophagus is innervated by the sympathetic nerves and parasympathetic supply from the vagus nerve ([[Cranial Nerves - Anatomy & Physiology|CN X]]) and recurrent laryngeal nerves. The myenteric plexus extends the length of the oesophagus.
 
 
*Parasympathetic from the vagus nerve ([[Nervous System - CNS - Anatomy & Physiology#Innervation - Cranial Nerves|CN X]]) and recurrent laryngeal nerves
 
 
 
*Myenteric plexus extends the length of the oesophagus
 
 
 
  
 
==Species Differences==
 
==Species Differences==
  
*Mucous glands present in horse, cats and ruminants only at pharyngeal-oesophageal junction
+
Mucous glands are present in the horse, cats and ruminants only at the pharyngeal-oesophageal junctionRuminants, horse and pig have stratified squamous epithelium continuing from the oesophagus into the stomach. Carnivores have an abrupt transition to columnar epithelium.
 
 
*Thick and strong sphincter of tunica muscularis in dogs and pigs
 
 
 
*Ruminants, horse and pig have stratified squamous epithelium continuing from oesophagus into [[Forestomach - Anatomy & Physiology|stomach]]. Carnivores have an abrupt transition to columnar epithelium.
 
  
 
===Canine===
 
===Canine===
*No keratinisation
+
No keratinisation, the '''lamina muscularis''' is skeletal muscle and is present caudally (spirally aranged). The lamina muscularis is, however, absent cranially. Mucous glands are present throughout but more abundant caudally. There is a thick and strong sphincter of tunica muscularis.
 
 
*Lamina muscularis present caudally (spirally aranged)
 
 
 
*Lamina muscularis absent cranially  
 
 
 
*Mucous glands throughout but more abundant caudally
 
  
 
===Equine===
 
===Equine===
*Some keratinisation
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Some keratinisation is present. It is larger, less wide and less dilatable as bovines, 50-60 inches long and having 3 parts.
  
 
===Ruminant===
 
===Ruminant===
*Heavily keratinised
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Heavily keratinised.
  
 
===Porcine===
 
===Porcine===
*Lamina muscularis present caudally (very thick)  
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The lamina muscularis is present caudally (very thick) and absent cranially. There is some keratinisation. Mucous glands are abundant cranially but absent caudally. There is a thick and strong sphincter of tunica muscularis.
  
*Lamina muscularis absent cranially
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===Avian===
 +
See [[Crop - Anatomy and Physiology|the crop]]. '''Ducks''' have an oesophangeal [[Tonsils - Anatomy & Physiology|tonsil]] present in the caudal segment of the oesophagus.
  
*Some keratinisation
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==Links==
  
*Mucous glands abundant cranially but absent caudally
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'''Click here for information on [[:Category:Oesophagus - Pathology|Oesophagus Pathology]]'''
  
===Avian===
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'''Click here for information on [[Megaoesophagus]].
*See [[Crop- Anatomy and Physiology|the crop]]
 
  
*Ducks have an oesophangeal [[Tonsils - Anatomy & Physiology|tonsil]] present in the caudal segment of oesophagus
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{{Template:Learning
 
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|flashcards = [[Oesophagus - Anatomy & Physiology - Flashcards|Oesophagus flashcards]]
==Links==
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|powerpoints = [[Gastrointestinal Tract Histology resource|Histology of the oesophagus - see part 1]]
 
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|Vetstream = [https://www.vetstream.com/canis/search?s=oesophagus Clinical approach to oesophageal diseases]
[[Oesophagus - Anatomy & Physiology - Flashcards|Oesophagus Flashcards]]
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}}
  
[[Oesophagus - Pathology|Oesophagus Pathology]]
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==Webinars==
 +
<rss max="10" highlight="none">https://www.thewebinarvet.com/gastroenterology-and-nutrition/webinars/feed</rss>
  
[[Oesophagus - Pathology#Megoesophagus Secondary to Dextra-Aorta|Megoesophagus]]
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[[Category:Alimentary System - Anatomy & Physiology]]
 +
[[Category:Oesophagus]]
 +
[[Category:A&P Done]]

Latest revision as of 19:37, 27 October 2022


Introduction

The oesophagus (or gullet) is a muscular tube which transports food from the pharynx to the stomach. A bolus of food is passed down the oesophagus by peristalsis. The oesophagus is divided into cervical, thoracic and abdominal sections.

Structure and Function

Oesophagus Anatomy - Copyright RVC 2008

The oesophagus begins dorsal to the cricoid cartilage of the larynx. It follows the trachea down the neck, first on the left and then medially once in thorax in the mediastinum. It passes over the heart then through the oesophageal hiatus of the diaphragm. It passes over the dorsal border of the liver then joins the stomach at the cardia. The cervical section is accompanied by the common carotid artery, the vagosympathetic trunk and the recurrent laryngeal nerves. The thoracic section is accompanied by the right and left vagus nerves (CN X).

There are different proportions of striated muscle across the species;

Dog and ruminant = 100%
Cat = 80% (rostral)
Horse = 65% (rostral)
Pig = 33% (rostral)

Histology

Oesophagus Histology (Rat) - Copyright RVC 2008

The oesophagus has a stratified squamous epithelium. It has mucosal folds present for distension. The degree of keratinisation of the oesophagus depends on the animal's diet.

The lamina propria of the oesophagus contains collagen and elastic fibres that are sparsely distributed. The lamina muscularis of the oesophagus is smooth or skeletal muscle, depending on the species. The inner circular layer of the tunica muscularis thickens near the gastric junction, forming a sphincter.

Whilst there are no glands present in the mucosa, there are mucous glands (tubulo-acinar) present in the submucosa.

Innervation

The oesophagus is innervated by the sympathetic nerves and parasympathetic supply from the vagus nerve (CN X) and recurrent laryngeal nerves. The myenteric plexus extends the length of the oesophagus.

Species Differences

Mucous glands are present in the horse, cats and ruminants only at the pharyngeal-oesophageal junction. Ruminants, horse and pig have stratified squamous epithelium continuing from the oesophagus into the stomach. Carnivores have an abrupt transition to columnar epithelium.

Canine

No keratinisation, the lamina muscularis is skeletal muscle and is present caudally (spirally aranged). The lamina muscularis is, however, absent cranially. Mucous glands are present throughout but more abundant caudally. There is a thick and strong sphincter of tunica muscularis.

Equine

Some keratinisation is present. It is larger, less wide and less dilatable as bovines, 50-60 inches long and having 3 parts.

Ruminant

Heavily keratinised.

Porcine

The lamina muscularis is present caudally (very thick) and absent cranially. There is some keratinisation. Mucous glands are abundant cranially but absent caudally. There is a thick and strong sphincter of tunica muscularis.

Avian

See the crop. Ducks have an oesophangeal tonsil present in the caudal segment of the oesophagus.

Links

Click here for information on Oesophagus Pathology

Click here for information on Megaoesophagus.


Oesophagus - Anatomy & Physiology Learning Resources
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Vetstream
To reach the Vetstream content, please select
Canis, Felis, Lapis or Equis
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Flashcards
Test your knowledge using flashcard type questions
Oesophagus flashcards
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PowerPoint
Selection of relevant PowerPoint tutorials
Histology of the oesophagus - see part 1


Webinars

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