Changes

==Introduction==

==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 [http://en.wikipedia.org/wiki/Peristalsis| peristalsis].

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 [http://en.wikipedia.org/wiki/Peristalsis| peristalsis]. The oesophagus is divided into cevical, 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|150px|Oesophagus Anatomy - Copyright RVC 2008]]

[[Image:Oesophagus anatomy.jpg|thumb|right|250px|Oesophagus Anatomy - Copyright RVC 2008]]

*Begins dorsal to cricoid cartilage of [[Larynx - Anatomy & Physiology|larynx]]

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]]). 

 

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

 

*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 [[Monogastric Stomach - Anatomy & Physiology|stomach]] at the cardia

There are different proportions of striated muscle across the species;

 

 

*Different proportions of striated muscle across the species

**Dog and ruminant = 100%

**Dog and ruminant = 100%

**Cat              = 80% (rostral)

**Cat              = 80% (rostral)

**Horse            = 65% (rostral)

**Horse            = 65% (rostral)

**Pig              = 33% (rostral)

**Pig              = 33% (rostral)

==Innervation==

==Innervation==

*Sympathetic nerves

The oesophagus is innervated by the sympathetic nerves and parasympathetic 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 ([[Cranial Nerves - Anatomy & Physiology|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 junction. There is a thick and strong sphincter of tunica muscularis in dogs and pigs. Ruminants, horse and pig have stratified squamous epithelium continuing from the oesophagus into the [[Monogastric Stomach - Anatomy & Physiology|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 [[Monogastric Stomach - 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.

 

*Lamina muscularis is skeletal muscle

 

*Lamina muscularis present caudally (spirally aranged)

 

*Lamina muscularis absent cranially  

 

*Mucous glands throughout but more abundant caudally

===Equine===

===Equine===

*Some keratinisation

Some keratinisation.

===Ruminant===

===Ruminant===

*Heavily keratinised

Heavily keratinised.

===Porcine===

===Porcine===

*Lamina muscularis present caudally (very thick)  

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

 

*Lamina muscularis absent cranially  

 

*Some keratinisation

 

*Mucous glands abundant cranially but absent caudally

===Avian===

===Avian===

*See [[Crop - Anatomy and Physiology|the crop]]

See [[Crop - Anatomy and Physiology|the crop]]. '''Ducks''' have an oesophangeal [[Tonsils - Anatomy & Physiology|tonsil]] present in the caudal segment of the oesophagus.

*Ducks have an oesophangeal [[Tonsils - Anatomy & Physiology|tonsil]] present in the caudal segment of oesophagus

'''Test yourself with the [[Oesophagus - Anatomy & Physiology - Flashcards|Oesophagus Flashcards]]'''

==Test yourself with the Oesophagus flashcards==

==Links==

[[Oesophagus - Anatomy & Physiology - Flashcards|Oesophagus Flashcards]]

'''Test yourself with the [[Oesophagus - Anatomy & Physiology - Flashcards|Oesophagus Flashcards]]'''

[[:Category:Oesophagus - Pathology|Oesophagus Pathology]]

'''Click here for information on [[:Category:Oesophagus - Pathology|Oesophagus Pathology]]'''

[[Megaoesophagus]]

'''Click here for information on [[Megaoesophagus]].

[[Category:Alimentary System - Anatomy & Physiology]]

[[Category:Alimentary System - Anatomy & Physiology]]

[[Category:Oesophagus]]

[[Category:Oesophagus]]

[[Category:To Do - A&P]]

[[Category:To Do - AimeeHicks]]