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Download SALC07 Biological Sciences Head & Neck 4: Normal Swallow
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SALC07 Biological Sciences Head & Neck 4: The Typical Adult Swallow Flora Hall MCRSLT/HPC [email protected] Review of oral & pharyngeal anatomy Cavities of the oropharynx: Oral Nasal Oropharynx, naso- and laryngopharynx Pharynx The oral cavity Extends from oral opening (lips) to pillars of fauces at back Teeth and alveolar ridge or maxillae make up lateral margins Soft palate •Uvula •Velum Pillars of fauces •Anterior •Posterior Also known as glossopharyngeal arch Muscles of the velum Muscle Function Levator veli palatine Elevator *also movement of Eustachian tube Musculus uvulae Elevator/bunching Tensor veli palatine Tenses and shortens Palatoglossus Depressor Palatopharyngeus Depressor The pharynx Divided into areas: 1. Oropharynx 2. Nasopharynx 3. Laryngopharynx Pharyngeal muscles Superior pharyngeal constrictor Middle pharyngeal constrictor Inferior pharyngeal constrictors Muscle function Innervation Superior pharyngeal constrictor Velopharyngeal closure Reduces diameter CN XI & X Middle pharyngeal constrictor Reduces diameter CN XI & X Inferior pharyngeal constrictor Reduces diameter: Two parts: CN XI & X 1. Cricopharyngeal muscle *arises from cricoid Muscular orifice of oesophagus Pharyngeal musculature 2. Thyropharyngeal muscle *arises from thyroid Salpingopharyngeus Elevates lateral pharyngeal wall CN XI & X Stylopharyngeus Elevates pharynx CN IX Intrinsic tongue muscles The epiglottis Leaf-shaped cartilage Attached to root of tongue and hyoid Pharyngeal spaces and places Valleculae Laryngeal vestibule Pyriform sinuses Upper Oesophageal Sphincter Anatomical differences infants/adults The infant pharynx Pharynx generally curved from nasopharynx to hypopharynx With growth the gentle curve gradually changes to become closer to 90’ angle seen in adults Nasal breathing Small oral cavity Close proximity of tongue, soft palate and pharynx with the larynx appears to facilitate nasal breathing The typical adult swallow Swallowing Eating and Drinking Feeding Swallowing Deglutition: “ a complex process involving neuromuscular control and coordination, sensory perception, integration of the autonomic and somatic nervous systems and respiratory function” (RCSLT 2006) Label the following Nasal cavity Teeth Lips Pharynx Epiglottis Larynx Vocal Folds Soft Palate Tongue Trachea Oesophagus Lungs Stomach Pharynx http://www.youtube.com/watch?v=pNcV6 yAfq-g Swallowing Commonly divided into 4 stages: Pre-oral stage Oral stage (Oral preparation and oral transit) Pharyngeal stage Oesophageal stage Pre-Oral Anticipation Hunger Likes/Dislikes Mood Cognitive status Physical status Oral phase: 2 Parts; 1.Oral preparatory 2. To organise food/liquid in the mouth into a coherent bolus ready for swallowing Oral/Oral Transit To propel the bolus to the back of the mouth and trigger the pharyngeal stage of swallowing Oral Preparatory Begins when food/liquid enters mouth at level of lips Nasal airway dependent-oral closure required Voluntary control Time-dependent on range of factors Ends when bolus is formed and held ready for transit Oral Stage: Prep Oral Prep continued Lips & jaw close, increased buccal tone Range of complex and integrated tongue movements to form bolus Liquid bolus cupped Solid bolus-’tippers’ & ‘dippers’ Larynx & pharynx at rest, airway open Chewing; as required. Food mixed with saliva If not chewing, velum pulled anteriorally to rest on base of tongue-prevents spillage into pharynx & allows for variation in intra-oral pressure Chewing skills Requires lateral, rotary and grinding movements of tongue and jaw Lateral and rotary tongue>jaw Intermittent lip closure-Complete lip seal Grinding movements Oral Stage: Transit Intact labial seal Anterior to posterior tongue movement, begins ‘stripping’ action Soft palate elevates and closes nasal airway Oral stage: Transit Pharyngeal stage Pharyngeal Stage Oesophageal Stage Cricopharyngeal sphincter relaxes and is pulled open Bolus passes into oesophagus CP sphincter closes Structures return to resting position Lower eosophageal sphincter relaxes Oesophageal stage Breathing and swallowing Breath is held during the swallow This is called APNOEA When something goes wrong: Airway penetration Aspiration Silent Aspiration Choking Breathing and swallowing • Cough response: – – Needs intact sensory input from superior laryngeal nerve (X) and effective glottic closure Voluntary cough may be present, but if no sensation in laryngeal vestibule, aspiration may still occur The typical swallow, anatomy again. Why is it like that? Variations in normal swallowing Age Related Changes to the Swallow Any metabolic, biochemical and physiological processes change with increasing age. Notably: Oral/pharyngeal motor function Dentition Hunger Vision Salivation Taste Neural Regulation of Swallowing Neural control of swallowing Cortex Peri Nucleus tractus solitarius Medulla Peripheral afferent inputs (CN’s) Nucleus ambiguous Motor response (CN’s) Cranial Nerves – CN V -- Trigeminal • • – CN VII -- Facial • • – contains both sensory and motor fibers that innervate the face important in chewing contains both sensory and motor fibers important for sensation of oropharynx & taste to anterior 2/3 of tongue CN IX -- Glossopharyngeal • • contains both sensory and motor fibers important for taste to posterior tongue, sensory and motor functions of the pharynx Cranial Nerves CN X -- Vagus contains both sensory and motor fibers important for taste to oropharynx, and sensation and motor function to larynx and laryngopharynx. important for airway protection CN XII -- Hypoglossal contains motor fibers that primarily innervate the tongue Is that all there is to it?
