Week 5 Content

Neural basis of swallowing and speech

Implications of dysphagia

Malnutrition and dehydration, choking or death, aspiration, oral medications, quality of life, activity and participation

First stage of swallowing

Oral preparatory phase - voluntary

Second stage of swallowing

Oral transport phase - voluntary

Third stage of swallowing

Pharyngeal transport phase - involuntary

Fourth stage of swallowing

Oesophageal transport phase - involuntary

Key anatomical swallowing structures

Lips, teeth, hard and soft palate, mandible, tongue, epiglottis, larynx, oesophagus

Cortical structures involved in swallowing

Primary motor cortex and primary somatosensory cortex

Primary somatosensory cortex in swallowing

Receives information about joint position and jaw movement, muscles, lips and oral cavity about bolus size, temperature, shape

Subcortical structures involved in swallowing

Basal ganglia and limbic structures

Brainstem structure 1 involved in swallowing

Nucleus ambiguous = group of motor neurons located in medulla, contains cell bodies of neurons supplying soft palate, pharynx, larynx

Brainstem structure 2 involved in swallowing

Nucleus tractus solitarius = group of sensory neurons located in medulla, related to sense of taste

Trigeminal nerve and swallowing

Motor for muscles of mastication, sensory for face and mouth

Facial nerve and swallowing

Motor for muscles of facial expression, eye and lip closure, sensory for anterior two thirds of tongue for taste and saliva production

Glossopharyngeal nerve and swallowing

Motor for stylopharyngeus muscle, sensory for palate, oropharynx and posterior third of tongue for taste

Vagus nerve and swallowing

Motor for larynx, pharynx and soft palate, sensory for pharynx and larynx, taste from epiglottis and pharynx

Hypoglossal nerve and swallowing

Motor for muscles of tongue

Gag reflex testing

Tests pharyngeal sensation, provides information about integrity of sensory fibres of glossopharyngeal nerve

First class of movement - voluntary

Complex actions, purposeful and goal orientated, learnt and improved with practice

Second class of movement - rhythmic motor patterns

Combines voluntary and reflexive acts, initiation and termination is voluntary but reflexive once initiated

Third class of movement - reflexes

Involuntary, rapid, stereotyped movements, triggered by a stimulus, innate

Chewing and rhythmic motor patterns

Process that voluntarily starts and stops - open and closing of jaw is voluntary but movement is maintained until voluntary stop