Pharynx ANATOMY AND PHYSIOLOGY

Pharynx

1. BRISSO ARACKAL

2. overview It lies behind the nose, mouth and larynx and is wider at its upper end. The upper part of the pharynx transmits only air, the lower part( below the inlet of the larynx) only food, but the middle part is a common passage for both air and food.

3. STRUCTURES ASSOCIATED WITH THE PHARYNX Superiorly : the inferior surface of the base of the skull. Inferiorly : it is continuous with the oesophages . Anteriorly : the wall is incomplete because of the openings into the nose, mouth and larynx. Posteriorly : areolar tissue, involuntary muscle and bodies of the first six cervical vertebrae.

4. DIVISION OF PHARYNX For descriptive purposes the pharynx is divided into three parts: NASOPHARYNX OROPHARYNX LARYNGOPHARYNX

5. THE NASOPHARYNX The nasal part of the pharynx lies behind the nose above the level of the soft palate. On its lateral walls are the two openings of the auditory tubes, one leading to each middle ear. On the posterior wall are the pharyngeal tonsils(adenoids) , consisting of lymphoid tissue. They are most prominent in children up to approximately 7 years of age. There after they gradually atrophy.

6. OROPHARYNX The oral part of the pharynx lies behind the mouth, extending from below the level of the soft palate to the level of the upper part of the body of the 3 rd cervical vertebra. The lateral walls of the pharynx blend with the soft palate to form two folds on each side. Between each pair of folds is a collection of lymphoid tissue called the palatine tonsil . The tonsil is almond shaped.

7. During swallowing ,the nasal and oral parts are separated by the soft palate and uvula. OROPHARYNX

8. THE LARYNGOPHARYNX The laryngeal part of the pharynx extends from the oropharynx above and continues as the oesophagus below, ie . From the level of the 3 rd to the 6 th cervical vertebrae.

9. FUNCTIONS OF PHARYNX Passageway for air and food. The pharynx is involved in both the respiratory and the digestive systems: air passes through the nasal and oral sections, and food through the oral and laryngeal sections. Warming and humidifying. By the same methods as in the nose, the air is further warmed and moistened as it passes through the pharynx.

10. Taste :there are olfactory nerve endings of the sense of taste in the epithelium of the oral and pharyngeal parts. Hearing : the auditory tube , extending from the nasopharynx to each middle ear , allows air to enter the middle ear. Satisfactory hearing depends on the presence of air at atmospheric pressure on each side of the tympanic membrane. FUNCTIONS OF PHARYNX

11. Protection : the lymphatic tissue of the pharyngeal and laryngeal tonsils produces antibodies in response to antigens , eg bacteria. The tonsils are larger in children and tend to atrophy in adults. Speech : the pharynx functions in speech , by acting as a resonating chamber for sound ascending from the larynx, it helps to give the voice its individual characteristics. FUNCTIONS OF PHARYNX