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==Introduction==

==Introduction==

[[Image:Developing Head.jpg|thumb|right|150px|Developing Head - Copyright RVC]]

[[Image:Developing Head.jpg|thumb|right|250px|Developing Head - from [[Oral Cavity Histology resource|Oral Cavity PowerPoint]] ]]

The pharynx is part of both the [[Cardiorespiratory System Overview - Anatomy & Physiology|respiratory]] and [[Alimentary System Overview - Anatomy & Physiology|digestive]] system. Both systems have entrances to the pharynx but they are separated from each other by the [[Soft Palate|soft palate]].  

The pharynx is part of both the [[Cardiorespiratory System Overview - Anatomy & Physiology|respiratory]] and [[Alimentary System Overview - Anatomy & Physiology|digestive]] system. Both systems have entrances to the pharynx but they are separated from each other by the [[Soft Palate|soft palate]].  

During exercise or during respiratory distress, the mouth can be used as an additional opening of the respiratory system and then the [[Oropharynx - Anatomy & Physiology|oropharynx]] also becomes an air-way.

During exercise or during respiratory distress, the mouth can be used as an additional opening of the respiratory system and then the [[Oropharynx - Anatomy & Physiology|oropharynx]] also becomes an air-way.

The pharynx can be split into different regions- the [[Oropharynx - Anatomy & Physiology|oropharynx]], [[Larynx - Anatomy & Physiology#Laryngeal Pharynx|laryngeal pharynx]] (sometimes referred to as the oesophageal pharynx) and the [[Nasopharynx - Anatomy & Physiology|nasopharynx]]

The pharynx can be split into different regions - the [[Oropharynx - Anatomy & Physiology|oropharynx]], [[Larynx - Anatomy & Physiology#Laryngeal Pharynx|laryngeal pharynx]] (sometimes referred to as the oesophageal pharynx) and the nasopharynx.

[[Image:Nasopharynx.jpg|thumb|right|150px|Nasopharynx Anatomy - Copyright RVC]]

[[Image:Nasopharynx.jpg|thumb|right|250px|Nasopharynx Anatomy - Copyright RVC]]

==Structure and Function==

==Structure and Function==

*Opening of the [[Larynx - Anatomy & Physiology|larynx]] is on the floor of the pharynx

The opening of the [[Larynx - Anatomy & Physiology|larynx]] is on the floor of the pharynx. Caudal and dorsal to the laryngeal opening is the opening into the [[Oesophagus - Anatomy & Physiology|oesophagus]]. In the dorsal region of the nasopharynx, there are paired openings into the auditory (eustachian) tubes. The lining of the middle ear cavity and auditory tube is continuous with that of the nasopharynx. The pharynx is located between the base of the skull and the first two cervical vertebrae dorsally and the [[Larynx - Anatomy & Physiology|larynx]] ventrally. The [[Skull and Facial Muscles - Anatomy & Physiology#Mandible (mandibula)|mandible]], pterygoid muscles and [[Hyoid Apparatus - Anatomy & Physiology|hyoid apparatus]] are located laterally. Laterally, two pairs of '''palatopharyngeal arches''' are present from the [[Soft Palate|soft palate]] to the [[Oesophagus - Anatomy & Physiology|oesophagus]].

 

[[Image:Pharynx Anatomy.jpg|thumb|right|250px|Pharynx Labelled - Copyright C.Clarkson and T.F.Fletcher University of Minnesota]]

*Caudal and dorsal to the laryngeal opening is the opening into the [[Oesophagus - Anatomy & Physiology|oesophagus]]

 

*In the dorsal region of the [[Nasopharynx - Anatomy & Physiology|nasopharynx]] there are paired openings into the Auditory (Eustacian) Tubes

 

*The lining of the middle ear cavity and auditory tube is continuous with that of the [[Nasopharynx - Anatomy & Physiology|nasopharynx]]

 

*Located between the base of the skull and the first two cervical vertebrae dorsally

 

*[[Larynx - Anatomy & Physiology|larynx]] ventrally

 

*[[Skull and Facial Muscles - Anatomy & Physiology#Mandible (mandibula)|Mandible]], pterygoid muscles and [[Hyoid Apparatus - Anatomy & Physiology|hyoid apparatus]] laterally

 

[[Image:Pharynx Anatomy.jpg|thumb|right|150px|Pharynx Labelled - Copyright C.Clarkson and T.F.Fletcher University of Minnesota]]

**Laterally, two pairs of palatopharyngeal arches are present from the [[Soft Palate|soft palate]] to the [[Oesophagus - Anatomy & Physiology|oesophagus]]

**The dorsal compartment is the [[Nasopharynx - Anatomy & Physiology|nasopharynx]]

**The rostral compartment is the [[Oropharynx - Anatomy & Physiology|oropharynx]]

 

*The [[Larynx - Anatomy & Physiology#Laryngeal Pharynx|laryngeal pharynx]] is separated from the [[Oropharynx - Anatomy & Physiology|oropharynx]] by the [[Epiglottis|epiglottis]]

*[[Tonsils - Anatomy & Physiology|Tonsils]] are present on the lateral walls of the [[Oropharynx - Anatomy & Physiology|oropharynx]]

The walls of the pharynx contain striated muscle. During [[Deglutition|swallowing]], the soft palate is raised which divides the pharynx into dorsal and ventral sections. The dorsal compartment is the nasopharynx and the rostral compartment is the [[Oropharynx - Anatomy & Physiology|oropharynx]]. The [[Larynx - Anatomy & Physiology#Laryngeal Pharynx|laryngeal pharynx]] is separated from the oropharynx by the [[Larynx - Anatomy & Physiology#Epiglottis|epiglottis]]. [[Tonsils - Anatomy & Physiology|Tonsils]] are present on the lateral walls of the oropharynx and are covered by flaps of mucosa.

**Covered by flaps of mucosa

*The pharynx plays an important role in [[Deglutition|deglutition]]

The pharynx plays an important role in [[Deglutition|deglutition]].

[[Image:Soft Palate Separating Pharyngeal Cavities.jpg|thumb|right|150x|Soft palate dividing the oropharynx and the nasopharynx - Copyright RVC]]

[[Image:Soft Palate Separating Pharyngeal Cavities.jpg|thumb|right|250x|Soft palate dividing the oropharynx and the nasopharynx - Copyright RVC]]

==Musculature==

==Musculature==

===Muscles that constrict===

===Muscles that constrict===

 

Muscles that constrict the pharynx run dorsally to its roof. Rostral constrictor muscles are the '''hyopharyngeous''', '''pterygopharyngeous''' and the '''palatopharyngeous muscles'''. They originate from the [[Tonsils - Anatomy & Physiology#Pterygoid Bone (os pterygoideum)|pterygoid]] region of the skull and insert on the aponeurosis of the [[Soft Palate|soft palate]] and shorten the pharynx. The middle constrictor muscle is the '''thyopharyngeous muscle'''. It originates from the [[Hyoid Apparatus - Anatomy & Physiology|hyoid bone]]. Caudally is the '''cricopharyngeous muscle''', which originates from the [[Larynx - Anatomy & Physiology#Thyroid Cartilage|thyroid cartilage]] of the larynx.

*Run dorsally to roof of pharynx

 

*Rostral constrictor muscles are the '''hyopharyngeous''', '''pterygopharyngeous''' and the '''palatopharyngeous muscles'''

**Originate from the [[Tonsils - Anatomy & Physiology#Pterygoid Bone (os pterygoideum)|pterygoid]] region of the skull and the aponeurosis of the [[Soft Palate|soft palate]]

**Shorten the pharynx

 

*Middle constictor muscle is the '''thyopharyngeous muscle'''

**Origniates from the [[Hyoid Apparatus - Anatomy & Physiology|hyoid bone]]

 

*Caudal constictor muscles are the '''cricopharyngeous muscle'''

**Originates from the [[Larynx - Anatomy & Physiology#Thyroid Cartilage|thyroid cartilage]] of the [[Larynx - Anatomy & Physiology|larynx]]

===Muscles that dilate===

===Muscles that dilate===

 

Muscles that dilate the pharynx enclose it laterally and dorsally. The dilator muscle is the '''stylopharyngeous muscle'''. It originates from the hyoid apparatus and widens the rostral pharynx.

*Enclose pharynx laterally and dorsally

 

*Dilator muscle is the '''stylopharyngeous muscle'''

 

*Originates from the [[Hyoid Apparatus - Anatomy & Physiology|hyoid apparatus]]

 

*Widens the rostral pharynx

===Muscles that shorten===

===Muscles that shorten===

 

The '''pterygopharyngeal muscle''' and '''palatopharyngeal muscle''' shorten the pharynx. They enclose the pharynx laterally and dorsally.

*The '''pterygopharyngeal muscle''' and '''palatopharyngeal muscle''' shorten the pharynx

 

*Enclose pharynx laterally and dorsally

===Muscles that close the Pharyngeal Arch===

===Muscles that close the Pharyngeal Arch===

 

The '''palatopharyngeous muscle''' also closes the pharyngeal arch.

*The '''palatopharyngeous muscle''' also closes the pharyngeal arch

==Innervation==

==Innervation==

*Pharyngeal muscles arise from arch 4

The nervous supply comes from the pharyngeal branch of the vagus nerve ([[Cranial Nerves - Anatomy & Physiology|CN X]]) and from the cranial root of the accessory nerve ([[Cranial Nerves - Anatomy & Physiology|CN XI]]). The stylopharyngeous muscle is innervated by the glossopharyngeal nerve ([[Cranial Nerves - Anatomy & Physiology|CN IX]]).

*Pharyngeal branch of the vagus nerve ([[Cranial Nerves - Anatomy & Physiology|CN X]]) from the cranial root of the accessory nerve ([[Cranial Nerves - Anatomy & Physiology|CN XI]])

 

[[Image:Pharyngeal Tonsil.jpg|thumb|right|250px|Histology of Pharyngeal Tonsil - from the [[Lymphoid Tissue Histology resource|Lymphoid tissue histology PowerPoint]] ]]

*Stylopharyngeous muscle comes from arch 3 and is innervated by the accessory nerve ([[Cranial Nerves - Anatomy & Physiology|CN XI]])

'''Fibroelastic aponeurosis''' supports the mucosa. The nasopharynx has pseudostratified columnar epithelium. The [[Oropharynx - Anatomy & Physiology|oropharynx]] and the [[Larynx - Anatomy & Physiology#Laryngeal Pharynx|laryngeal pharynx]] have stratified squamous epithelium. The oropharynx and the laryngeal pharynx also have [[Salivary Glands - Anatomy & Physiology|salivary glands]] present.

*Glossopharyngeal nerve ([[Cranial Nerves - Anatomy & Physiology|CN IX]])  supplies taste to the pharynx

 

==[[Pharynx - Histology|Histology]]==

==Species Differences==

==Species Differences==

[[Image:Pharynx Anatomy.jpg|thumb|right|150px|Palatine Tonsil - Copyright C.Clarkson and T.F.Fletcher University of Minnesota]]

[[Image:Pharynx Anatomy.jpg|thumb|right|250px|Palatine Tonsil - Copyright C.Clarkson and T.F.Fletcher University of Minnesota]]

====Canine====

====Canine====

*Single duct connects [[Nasopharynx - Anatomy & Physiology|nasopharynx]] to the [[Nasal Cavity - Anatomy & Physiology|nasal cavity]]

A single duct connects the nasopharynx to the [[Nasal Cavity - Anatomy & Physiology|nasal cavity]]. The [[Tonsils - Anatomy & Physiology|tonsils]] are a compact mass which point away from the lumen of the pharynx.

 

*[[Tonsils - Anatomy & Physiology|Tonsils]] are a compact mass which point away from the lumen of the pharynx

====Equine====

====Equine====

*Auditory tube opens into the [[Ear - Anatomy & Physiology#Equine Guttural Pouch|guttural pouch]]

The auditory tube opens into the [[Ear - Anatomy & Physiology#Equine Guttural Pouch|guttural pouch]] and the tonsils are diffuse and raised slightly. Horses are unable to breathe through the mouth as the free apex of the rostral epiglottis lies dorsal to the soft palate in a normal horse.

 

*[[Tonsils - Anatomy & Physiology|Tonsils]] are diffuse and raised slightly

 

*Horses are unable to breathe through the mouth as the free apex of the rostral epiglottis lies dorsal to the soft palate in a normal horse.

====Ruminants====

====Ruminants====

*[[Tonsils - Anatomy & Physiology|Tonsils]] are a compact mass which point towards the lumen of the pharynx

Tonsils are a compact mass which point towards the lumen of the pharynx.

==Links==

==Links==

[[Oropharynx - Anatomy & Physiology|Oropharynx - Anatomy & Physiology]]

Click here for more information on the [[Oropharynx - Anatomy & Physiology|oropharynx]].

Click here for more information on the [[Larynx - Anatomy & Physiology#Laryngeal Pharynx|laryngeal pharynx]].

 

[[Larynx - Anatomy & Physiology#Laryngeal Pharynx|laryngeal pharynx]]

 

 

 

 

 

 

 

[[Category:Respiratory System - Anatomy & Physiology]][[Category:Musculoskeletal System - Anatomy & Physiology]]

[[Category:Respiratory System - Anatomy & Physiology]][[Category:Musculoskeletal System - Anatomy & Physiology]]

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[[Category:A&P Done]]