Salivation And Swallowing

Question 0

Describe what can happen if there is a lack of saliva

Answer 0

Xerostomia

Teeth and mucosa degrade - teeth rot, mouth ulcers

Question 1

Describe the functions of saliva

Answer 1

Lubricates and wets food
Starts digestion or carbohydrates (amylase)
Protects oral environment - moist mucosa, washes teeth, alkaline environment, increased calcium

Question 2

List the components of saliva secreted by each pair of salivary glands

Answer 2

25% Paroid - serous (increased enzymes, low mucus)
5% Sublingual - mucous (no enzymes, increased mucus)
70% Sub mandibular - mixed

Question 3

Explain the mechanisms of secretion of serous saliva

Answer 3

Acinar cells control volume (isotonic with ECF)
Ductal cells control composition
More rapidly saliva produced = less modified

Question 4

Describe the constituents of saliva

Answer 4

Water, electrolytes (low NaCl, high calcium, K+, I-), alkali, bacteriostats, mucus, enzymes

Question 5

Explain the difference between the composition of resting and stimulated saliva

Answer 5

Resting saliva - highly modified, low volume, hypotonic, neutral, few enzymes
Stimulated saliva - less modified, increased column, less hypotonic, alkaline, many enzymes

Question 6

Describe the control of salivary secretion

Answer 6

ANS:
Sympathetic - superior cervical ganglion
Parasympathetic - glossopharyngeal, optic ganglion

Question 7

Describe the structure of the oesophagus and outline its function

Answer 7

Fibromuscular passage that allows food to pass through, aided by peristaltic contractions, from pharynx to the stomach

Question 8

Describe the processes of swallowing

Answer 8

Voluntary - bolus into pharynx
Pharyngeal - pressure receptors inhibits respiration, raises larynx, closes glottis, opens upper oesophageal sphincter
Oesophageal - upper third voluntary, lower two thirds smooth muscle, rapid peristaltic wave, 9s transit time

Question 9

Outline the anatomical relationships of the oesophagus and how disordered swallowing may occur on a result of a primary oesophageal disorder or a condition in a closely related structure

Answer 9

In between pharynx and stomach
Problems:
Obstruction/compression due to tumours
Lack of motility due to achalasia

Question 10

Categorise different types of dysphagia based on the underlying pathology

Answer 10

Oesophageal dysphagia - difficulty swallowing solids due to tumour, constriction
Oropharyngeal dysphagia - difficulty swallowing liquids due to stroke, bulbarpalsy, psuedobulbarpalsy

Question 11

Describe the anatomical mechanisms that prevent gastrooesophageal reflux and outline some of the clinical consequences of free gastrooesophageal reflux

Answer 11

Oesophagus enters obliquely into stomach
Stomach relaxes and expands as it fills
Constriction of upper and lower oesophageal sphincters
Lower crux of diaphragm
Clinical consequences - Barrett’s oesophagus (metaplasia, stratified squamous –> simple columnar), heart burn