Pharynx
By Wikipedia,
the free encyclopedia,
http://en.wikipedia.org/wiki/Pharynx
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The pharynx (plural: pharynges) is the part
of the neck
and throat
situated immediately posterior
to (behind) the mouth
and nasal
cavity, and cranial,
or superior, to the oesophagus,
larynx,
and trachea.
Functions
It is part of the digestive
system and respiratory
system of many organisms.
Because both food
and air
pass through the pharynx, a flap of connective tissue called
the epiglottis
closes over the trachea when food is swallowed to prevent
choking
or aspiration.
In humans
the pharynx is important in vocalization.
In persons with hayfever,
oral
allergy syndrome and related allergies, the pharynx
is often a reaction site to allergens, with common symptoms
including burning and itching.
Parts
The human pharynx is conventionally divided into three
sections:
Oropharynx
The oropharynx
lies behind the oral cavity. The anterior wall consists
of the base of the tongue and the vallecula; the lateral
wall is made up of the tonsil, tonsillar fossa, and tonsillar
(faucial) pillars; the superior wall consists of the inferior
surface of the soft palate and the uvula.
Nasopharynx
The nasopharynx
lies behind the nasal
cavity.
Postero-superiorly this extends from the level of the junction
of the hard and soft palates to the base of skull, laterally
to include the fossa
of Rosenmuller.
The inferior wall consists of the superior surface of the
soft palate.
Laryngopharynx
The laryngopharynx,
also known as the hypopharynx,
roughly corresponds to the levels between C4 to C6, it includes
the pharyngo-esophageal junction (postcricoid area), the
piriform
sinus, and the posterior pharyngeal wall.
Like the oropharynx above it the hypopharynx serves as
a passageway for food and air and is lined with a stratified
squamous epithelium.
It lies inferior to the upright epiglottis and extends
to the larynx, where the respiratory and digestive pathways
diverge.
At that point, the laryngopharynx is continuous with the
esophagus posteriorly. The esophagus conducts food and fluids
to the stomach;
air enters the larynx anteriorly. During swallowing, food
has the "right of way", and air passage temporarily stops.
Additional images
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Conducting passages
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Organs of the digestive system
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The entrance to the larynx, viewed from behind.
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Sagittal section of nose mouth, pharynx, and larynx
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| The position and relation of
the esophagus in the cervical region and in the posterior
mediastinum. Seen from behind |
References
- Stedman's/LWW
1551471
- Human Anatomy and Physiology Elaine N. Marieb
and Katja Hoehn, Seventh Edition.
- TNM Classification of Malignant Tumours Sobin
LH & Wittekind Ch (eds)Sixth edition UICC 2002 ISBN
0-471-22288-7
See also
External links
Source: http://en.wikipedia.org/wiki/Pharynx
Published - November 2008
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