PHTY101 Lecture Notes - Lecture 9: Vagus Nerve, Soft Palate, Pharyngeal Muscles
Document Summary
First stage: food from mouth to pharynx, voluntary, muscle activities: Involves muscles of the cheeks, tongue and oral cavity: buccinators- prevent food from moving lateral to teeth, suprahyoid muscles- raise the floor of mouth, extrinsic tongue muscles- raise sides of tongue and depress midline of. Intrinsic tongue muscles- elevate anterior tongue to the hard palate. Involves muscles of soft palate and pharynx: food passes through pharynx to oesophagus, aim to move food through pharynx towards oesophagus, muscle activity: Internal (longitudinal) pharyngeal muscles elevate pharynx: soft palate elevates to close nasopharyngeal opening, suprahyoids pull hyoid up- closure of laryngeal inlet, tongue bulges in oropharyngeal opening to stop food re-entering the oral cavity. Internal and external (circular) pharyngeal muscles contract in coordinated manner, termed peristalsis- movement of food through pharynx to oesophagus. Functions: produce sound (phonation, protect lower airways, prevent entry of foreign objects, provide a mechanism to clear the lower airway e. g. cough.
