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Pharynx
- It is present in the upper part of the digestive
system. It extends from the base of the skull to c6 vertebra.
- Anteriorly it is open and communicates with nasal
cavity, oral cavity and larynx.
- The part communicating with nasal cavity is called
as nasopharynx communicating with oral cavity is called as oropharynx, communicating with larynx is called laryngopharynx.
- Pharynx is the common passage for both air and food.
- In the laryngopharynx they get separated.
- Air will enter the larynx and food will enter the
oesophagus.
- Within the wall of pharynx, four layers are present
from inside outward they are mucosa, sub mucosa, muscular layer and adventitia.
- In the muscular layer, there are e pairs of circular
muscles ie superior constrictor, middle constrictor and inferior constrictor. 3
pairs of longitudinal muscles ie stylopharyngeus, palate pharyngeus and
salpingo pharyngeous.
- In the lateral walls of naso pharynx there are
opening for the auditory tubes, which will communicate the pharynx with the
middle layer cavity.
- In the roof of nasopharynx a collection of lumphatic
vessels is present known as nasopharyngeal tonsil.
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