PHARYNX::
It is a tubal space situated between the mouth and the oesophagus it is subdivided into three parts: 1.Nasopharynx 2.Oropharynx and 3.Laryngopharynx the base of the skull forms its roof the nose and the mouth open into it in other words it is the junction between the oral and nasal cavity or oesophagus and larynx Adenoid or tonsil is a lymph node at the back of nasopharynx when it gets inflamed it obstructs nasal breathing such a child that breathes through mouth is called paranoid facies Tonsils hlep to trap bacteria and destroy them tonsils also help in immune responses
OESOPHAGUS:
It is a long hollow tube 25 cm in length and opens into the stomach at the cardiac orifice Food passes from the pharynx through the oesophagus to be finally pushed into the stomach the tube distends during the passage of food which is pushed downwards by contraction of the muscles its passage is through the neck and chest and finally opens into the stomach
Histologically oesophagus shows 3 layers : muscular layer sub mucosa and mucosa from external to internal serosa is absent in oesophagus because it lies out side the coelon muscular layer consists of striated muscles in the upper one third and smooth muscles in lower one third of the oesophagus middle portion consists of both the types of muscles submucosa consists of loose pliable connective tissue which houses nerve plexuses and blood vessels mucosa consists of long lamniapropria and mucous membrane lamnia propria is made up of loose aerolar connective tissue with lymphatics
The bolus which is formed in the oral cavity is passed into stomach through pharynx and oesophagus by process of deglutition during this passage of the nasal cavity is closed the bolus moves down in the oesophagus by peristalsis
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