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Download PARTS OF THE PHARYNX THE PHARYNX Skeleton THE
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HFA 213 Week 11 the Pharynx 1 2 PARTS OF THE PHARYNX THE PHARYNX Skeleton Nasopharynx Above the level of the soft palate Choanae (posterior nasal openings) Auditory tube (Eustachian tube) Adenoid tonsils Levator palati Salpingopharyngeus muscle Medial pterygoid plates Pterygomandibular raphe Mandibular tuberosity Hyoid bone Greater and lesser horns Stylohyoid ligament Thyroid cartilage Cricoid cartilage Oropharynx Below the soft palate Uvula Behind the palatoglossus muscle Palatine tonsil (fauces) Palatopharyngeus muscle Posterior 1/3 of tongue Median and lateral glossoepiglotic folds Valleculae Laryngopharynx Behind the opening of the larynx Epiglottis Aryepiglottic folds Arytenoid cartilages Piriform recesses Posterior edge of thyroid laminae Posterior aspect of the cricoid lamina Pharynx ends at the level of the cricoid ring HFA 213 Week 11 the Pharynx 3 4 THE PHARYNX Constrictor muscles ALL Origin from the pharyngeal skeleton Insert into a midline raphe posteriorly (meets the one from the opposite side) Superior constrictor From the pterygomandibular raphe (and the bone at either end) Middle constrictor From the hyoid bone (greater and lesser horns) THE PHARYNX Longitudinal muscles Lie inside the circular coat -- unlike the rest of the GIT Three longitudinal muscles take origin from the base of the skull Stylopharyngeus from the styloid process Palatopharyngeus from the soft palate Salpingopharyngeus from the auditory tube (salpinx = tube) Inferior constrictor From the thyroid and cricoid cartilages Cricopharyngeus at the junction of pharynx and oesophagus. “Flower pots” - the lower constrictors overlap the one above Palatopharyngeus and Salpingopharyngeus are inside the pharynx from the origin All the nerves and vessels that supply the pharynx (and larynx) must enter in the gaps above or Stylopharyngeus takes origin outside the pharynx, and has to pass between the superior below the constrictors and middle constrictors to get inside the pharynx HFA 213 Week 11 the Pharynx 5 6 DEGLUTITION = SWALLOWING THE PHARYNX Nerve supply 3 Phases Things to avoid Sensory supply: Glossopharyngeal nerve Food must not go into the nose Food must not be forced back into the mouth Food must not go into the larynx Motor supply: 1. Vagus nerve supplies the muscles of pharynx, larynx and palate ie. constrictors, palato and salpingopharyngeus 2. Glossopharyngeal nerve supplies one muscle => stylopharyngeus Oral phase Voluntary - duration variable Tongue gathers bolus - to roof of mouth, then backwards Soft palate contracts to seal off nasopharynx from oropharynx At the end of the oral phase the bolus is thrown into the pharynx And palatoglossus contracts to seal off the oropharynx from the mouth The pharyngeal plexus lies in the loose connective tissue coat surrounding the pharynx (buccopharyngeal fascia). It receives pharyngeal branches of the vagus and glossopharyngeal nerves Pharyngeal phase Reflex - fraction of a second Reflex is triggered when the bolus touches the oropharynx (CN IX) The longitudinal muscles contract Raising the larynx (helping to fold the epiglottis and seal off the airway) Pulling the pharynx up over the bolus Then circular/constrictor muscles contract and the longitudinal ones relax Carrying the bolus down Peristaltic contractions then take over The gag reflex: when you touch the back of your throat (oropharynx) it triggers a reflex contraction of the pharyngeal muscles Sensory limb = glossopharyngeal nerve Processsing centre = Medulla of brain Motor limb = vagus nerve and pharyngeal muscles Like any reflex test this reflex tests all these components Oesophageal phase Involuntary - slow - may take up to a minute The upper part of the Oesophagus is voluntary muscle Middle part is mixed smooth and voluntary muscle Lower part is smooth muscle HFA 213 Week 11 the Pharynx STRUCTURES ENTERING THE PHARYNX Above superior constrictor Salpingopharyngeus Auditory tube Levator palati Ascending palatine artery Between superior constrictor and middle constrictor Lingual nerve Lingual artery Hypoglossal nerve Stylopharyngeus Glossopharyngeal nerve Submandibular duct Between middle constrictor and inferior constrictor Internal laryngeal nerve and superior laryngeal artery Below inferior constrictor Recurrent laryngeal nerve and inferior laryngeal artery 7 8 The Pharynx
