Mouth, Pharynx And Oesophagus Physiology Flashcards
what do the following secrete
parotid glands
submandibular glands
sublingual glands
serous acini
mixed acini
mainly mucous acini
composition of saliva
ions, pH 6.2-8.0, mucin, digestive enzymes (amylase and lipase), antibacterial agents, immunoglobulins, phosphoproteins, blood group factors
average saliva secretion
0.5 ml/minute, 1-2 litres/day.
nervous control of saliva
control of ANS, predominantly parasympathetic. Parasympathetic incr. saliva.
Conditioned response to sight smell and thought of food. Unconditioned reflex due to stimulation of taste and mechanoreceptors
Functions of saliva
solvent, lubrication, digestion, protection
absorption in oral cavity
low Mw molecules e.g. alcohol
drugs e.g. GTN
structure that prevents food entering lungs
epiglottis
what sphincter sits at entrance to oesophagus
cricopharyngeus
pharynx slides freely on…
prevertebral fascia
swallowing - oral phase (voluntary)
bolus held on tongue respiration inhibited floor of mouth and hyoid, and therefore tongue, move posterosuperiorly. Palate elevates to close off nasopharynx bolus propelled into oropharynx
swallowing - pharyngeal (involuntary phase)
glottis closes larynx elevates epiglottis folds posteroinferiorly cricopharyngeus relaxes peristaltic wave directs bolus into oesophagus
swallowing - oesophageal phase (involuntary)
cricopharyngeus regains tone and palate relaxes
larynx falls, glottis opens and respiration recommences
peristaltic wave traverses oesophagus to stomach
secondary peristaltic wave may occur to clear residue
clinical assessment of swallowing
history observation (drink water) milk nasendoscopy contrast x-ray swallow manometry pH monitoring
separates nasal from oral cavity
hard palate
