s3. salivation and swallowing

Question 1

describe the composition of saliva

Answer 1

mostly water (hypotonic)
mucins - lubrication. highly osmotically active
amylase
lingual lipase
immune proteins

Question 2

functions of saliva

Answer 2

• lubrication of lips (cheeks over teeth to speak and sing)
• lubrication of food >to eat
• maintain dental hygiene
• immunological proteins kills microorganisms
• good solvent > dissolve flavour/ taste molecules

Question 3

what is xerostomia? causes? symptoms ?

Answer 3

dry mouth
as a result of compromised saliva production
or drug side effects (anticholinergic drugs) or autoimmune conditions

• bad breath
• sore, inflamed tongue
• poor teeth as no lubrication

Question 4

what happens in a mumps infection?

Answer 4

swollen parotid (parotiditis)
pressure within capsule builds up, can't escape > v painful!

Question 5

3 phases of swallowing?

Answer 5

oral preparatory phase
pharyngeal phase
oesophageal phase

Question 6

what occurs in oral preparatory phase of swallowing?

Answer 6

voluntary

• pushes bolus towards pharynx
• once bolus touches pharyngeal wall, pharyngeal phase begins

Question 7

what occurs in pharyngeal phase of swallowing?

Answer 7

involunary

• soft palate seeks off nasopharynx to prevent food going into nasal cavity
• pharyngeal constrictors push bolus downwards
• supra hyoid muscle causes larynx to elevate, closing epiglottis
• vocal cords adduct > protecting airway and breathing temporarily ceases
• opening of the upper oesophageal sphincter

Question 8

what occurs in oesophageal phase of swallowing?

Answer 8

involuntary

• closure of upper oesophageal sphincter
• peristaltic wave carries bolus downwards into oesophagus towards stomach

Question 9

how is it possible for babies to breathe and suck milk?

Answer 9

epiglottis extends up to nasopharynx so airway constantly open > only descends when neck lengthens and allows baby to speak.

milk goes behind epiglottis into oesophagus

Question 10

describe neural control of swallowing

Answer 10

mechanoreceptors in back of throat detect bolus
>glossopharyngeal nerve (CN 9)
>medulla
>vagus nerve
>pharyngeal constrictors

Question 11

what is dysphagia? common cause?

Answer 11

disordered swallowing

• stroke
• oesophageal tumour

Question 12

what is trans oesophageal echocardiogram?

Answer 12

imaging technique to view heart (left atrium is over the oesophagus)
probe down oesophagus

Question 13

key sites where food can get lodges in oesophagus

Answer 13

• junction of oesophagus with pharynx
• where oesophagus is crossed by arch of aorta
• where oesophagus is crossed by L main bronchus
• at diaphragm (T10)

Question 14

muscular composition of oesophagus?

Answer 14

top third- skeletal
middle - mix of skeletal and smooth
inferior third- smooth