Difference between revisions of "Oesophagus - Anatomy & Physiology"
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| − | {{ | + | {{toplink |
| + | |backcolour =BCED91 | ||
| + | |linkpage =Alimentary - Anatomy & Physiology | ||
| + | |linktext =Alimentary System | ||
| + | |maplink = Alimentary (Concept Map)- Anatomy & Physiology | ||
| + | |pagetype =Anatomy | ||
| + | }} | ||
| + | <br> | ||
==Introduction== | ==Introduction== | ||
| − | The oesophagus (or gullet) is a muscular tube which transports food from the [[Pharynx - Anatomy & Physiology|pharynx]] to the [[ | + | 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== | ==Structure and Function== | ||
| − | |||
| − | |||
| − | + | [[Image:Oesophagus anatomy.jpg|thumb|right|150px|Oesophagus Anatomy - Copyright RVC 2008]] | |
| − | + | *Begins dorsal to cricoid cartilage of [[Larynx - Anatomy & Physiology|larynx]] | |
| − | + | ||
| − | + | *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 [[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== | ==Histology== | ||
| − | |||
| − | |||
| − | + | [[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 or skeletal muscle (depending on species) | ||
| + | |||
| + | *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== | ==Innervation== | ||
| − | + | *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== | ==Species Differences== | ||
| − | Mucous glands | + | *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=== | ===Canine=== | ||
| − | No keratinisation | + | *No keratinisation |
| + | |||
| + | *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) | |
| + | |||
| + | *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 oesophagus | ||
==Links== | ==Links== | ||
| − | + | [[Oesophagus - Anatomy & Physiology - Flashcards|Oesophagus Flashcards]] | |
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| − | + | [[:Category:Oesophagus - Pathology|Oesophagus Pathology]] | |
| − | |||
| − | [[ | + | [[Megaoesophagus]] |
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| − | |||
Revision as of 12:00, 10 June 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
- 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
- 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
- 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 or skeletal muscle (depending on species)
- 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 is skeletal muscle
- 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