Difference between revisions of "Oesophagus - Anatomy & Physiology"

Revision as of 12:58, 28 May 2010

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 cevical, thoracic and abdominal sections.

Structure and Function

Oesophagus Anatomy - Copyright RVC 2008

Begins dorsal to cricoid cartilage of larynx

Follows trachea down neck, first on the left and then medially once in thorax in the mediastinum

Passes over heart then through the oesophageal hiatus of the diaphragm

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)

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

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

Inner circular layer of tunica muscularis thickens near gastric junction forming a sphincter

Innervation

Sympathetic nerves

Parasympathetic from the vagus nerve (CN X) and recurrent laryngeal nerves

Myenteric plexus extends the length of the oesophagus

Species Differences

Mucous glands present in horse, cats and ruminants only at pharyngeal-oesophageal junction

Thick and strong sphincter of tunica muscularis in dogs and pigs

Ruminants, horse and pig have stratified squamous epithelium continuing from oesophagus into stomach. Carnivores have an abrupt transition to columnar epithelium.

Canine

No keratinisation

Lamina muscularis present caudally (spirally aranged)

Lamina muscularis absent cranially

Mucous glands throughout but more abundant caudally

Equine

Some keratinisation

Ruminant

Heavily keratinised

Porcine

Lamina muscularis present caudally (very thick)

Lamina muscularis absent cranially

Some keratinisation

Mucous glands abundant cranially but absent caudally

Avian

See the crop

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

Links

Oesophagus Flashcards

Oesophagus Pathology

Megaoesophagus

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-{{OpenPagesTop}}
+{{toplink
+|backcolour =BCED91
+|linkpage =Alimentary - Anatomy & Physiology
+|linktext =Alimentary System
+|maplink = Alimentary (Concept Map)- Anatomy & Physiology
+|pagetype =Anatomy
+}}
+<br>
 ==Introduction==
-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 (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].
+The oesophagus is divided into cevical, thoracic and abdominal sections.
 ==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]]).
-There are different proportions of striated muscle across the species;
+[[Image:Oesophagus anatomy.jpg|thumb|right|150px|Oesophagus Anatomy - Copyright RVC 2008]]
-:Dog and ruminant = 100%
+*Begins dorsal to cricoid cartilage of [[Larynx - Anatomy & Physiology|larynx]]
-:Cat              = 80% (rostral)
-:Horse            = 65% (rostral)
+*Follows trachea down neck, first on the left and then medially once in thorax in the mediastinum
-: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 ([[Cranial Nerves - Anatomy & Physiology|CN X]])
+*Different proportions of striated muscle across the species
+**Dog and ruminant = 100%
+**Cat              = 80% (rostral)
+**Horse            = 65% (rostral)
+**Pig              = 33% (rostral)
 ==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.
-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.
+[[Image:Oesophagus Histology.jpg|thumb|right|150px|Oesophagus Histology (Rat) - Copyright RVC 2008]]
+*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
-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
 ==Innervation==
-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.
+*Sympathetic nerves
+*Parasympathetic from the vagus nerve ([[Cranial Nerves - Anatomy & Physiology|CN X]]) and recurrent laryngeal nerves
+*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.
+*Mucous glands present in horse, cats and ruminants only at pharyngeal-oesophageal junction
+*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===
-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.
+*No keratinisation
+*Lamina muscularis present caudally (spirally aranged)
+*Lamina muscularis absent cranially
+*Mucous glands throughout but more abundant caudally
 ===Equine===
-Some keratinisation is present. It is larger, less wide and less dilatable as bovines, 50-60 inches long and having 3 parts.
+*Some keratinisation
 ===Ruminant===
-Heavily keratinised.
+*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.
+*Lamina muscularis present caudally (very thick)
+*Lamina muscularis absent cranially
+*Some keratinisation
+*Mucous glands abundant cranially but absent caudally
 ===Avian===
-See [[Crop - Anatomy and Physiology|the crop]]. '''Ducks''' have an oesophangeal [[Tonsils - Anatomy & Physiology|tonsil]] present in the caudal segment of the oesophagus.
+*See [[Crop- Anatomy and Physiology|the crop]]
+*Ducks have an oesophangeal [[Tonsils - Anatomy & Physiology|tonsil]] present in the caudal segment of oesophagus
 ==Links==
-'''Click here for information on [[:Category:Oesophagus - Pathology|Oesophagus Pathology]]'''
+[[Oesophagus - Anatomy & Physiology - Flashcards|Oesophagus Flashcards]]
-'''Click here for information on [[Megaoesophagus]].
-{{Template:Learning
-|flashcards = [[Oesophagus - Anatomy & Physiology - Flashcards|Oesophagus flashcards]]
-|powerpoints = [[Gastrointestinal Tract Histology resource|Histology of the oesophagus - see part 1]]
-|Vetstream = [https://www.vetstream.com/canis/search?s=oesophagus Clinical approach to oesophageal diseases]
-}}
-==Webinars==
+[[:Category:Oesophagus - Pathology|Oesophagus Pathology]]
-<rss max="10" highlight="none">https://www.thewebinarvet.com/gastroenterology-and-nutrition/webinars/feed</rss>
-[[Category:Alimentary System - Anatomy & Physiology]]
+[[Megaoesophagus]]
-[[Category:Oesophagus]]
-[[Category:A&P Done]]