Salivation and Swallowing

Question 1

Describe the composition of saliva. (4)

Answer 1

Hypotonic
Rich in K+ and HCO3-
Contains mucins, amylase, lipase and immune proteins

Question 2

Describe the functions of saliva. (5)

Answer 2

Lubrication of the vocal cords 
Adds liquid to form a bolus
Helps maintain the oral cavity
Reduces food poisoning with immune attacks
Acts as a solvent.

Question 3

Describe xerostomia (4)

Answer 3

Dry mouth with signs of tooth decay, halitosis, redness, inflammation.
Sign itself of chronic dehydration or pathology.

Question 4

Describe the locations of the salivary glands. (6)

Answer 4

Parotid gland - superficial to masseter, inferoanterior to the ear.
Sublingual - anteriolateral inside the mandible.
Submandibular - medial inside the mandible.

Question 5

Describe the neural control of salivation.(2)

Answer 5

Mostly parasympathetic to increase secretion, but sympathetic can do a little bit.

Question 6

Describe drugs that can cause a dry mouth. (3)

Answer 6

Muscarinic receptor blockers - antipsychotics, overactive bladder, travel sickness.

Question 7

Describe the phases of swallowing. (10)

Answer 7

Oral preparatory phase: voluntary, pushes bolus towards pharynx, then pharyngeal phase begins on reflex.
Pharyngeal phase: involuntary, soft palate elevates to seal off nasopharynx, pharyngeal muscles push bolus down, larynx elevates and epiglottis shuts off airway, vocal cord adducts, breathing stops, upper oesophageal sphincter opens.
Oesophageal phase: involuntary, closure of the sphincter, peristalsis.

Question 8

Explain why babs can swallow and breathe. (2)

Answer 8

Their epiglottis projects up into the nasopharynx to separate swallowing and breathing.

Question 9

Describe the dysphagia seen in a stroke. (2)

Answer 9

Damaged neuropathway - liquids offer serious risk of aspiration pneumonia but solids tricky too.

Question 10

Describe the dysphagia seen in oesophageal tumour. (1)

Answer 10

Fluid swallowed much more easily than solids.

Question 11

Describe the 4 narrowing of the oesophagus.

Answer 11

Upper oesophageal sphincter
Arch of aorta
Left main bronchus
Lower oesophageal sphincter

Question 12

Describe the body’s methods of trying to prevent reflux. (3)

Answer 12

LOS
Compression of the intra-abdominal oesophagus when pressure rises.
Acute angle of entry of oesophagus into stomach creates a flap valve.

Question 13

Describe the concentration change of HCO3- in higher flow rates of saliva. (1)

Answer 13

Concentration of HCO3- increases.