Week 2 - Anatomy Of Salivation And Swallowing

Question 1

What is saliva composed of?

Answer 1

Mostly water, mucin, amylase, lingual lipase, immune proteins

Question 2

What is the pH of saliva?

Answer 2

7.4

Question 3

How does the flow rate affect the saliva?

Answer 3

It’s normally hypotonia as its had sodium and chlorine removed, in high flow its more isotonic

Question 4

What are the functions of saliva?

Answer 4

Helps keep teeth healthy, initiates digestion, solvent for taste molecules, lubrication

Question 5

What is xerostomia and what is its symptoms?

Answer 5

Dry mouth

May have sore inflamed tongue, sore lips, difficulty eating false teeth fall out, cavities, cant taste well

Question 6

What may cause xerostomia?

Answer 6

Cold, some medications e.g. Antidepressants, middle ear infection

Question 7

What are the three salivary glands and roughly where are they located?

Answer 7

Parotid gland - at back of jaw below ear
Sublingual gland - behind lower front teeth
Submandibular gland - lower and a bit posterior to sublingual gland

Question 8

What innervation the sublingual and submandibular glands?

Answer 8

7th cranial nerve

Question 9

What innervation the parotid gland?

Answer 9

9th cranial nerve

Question 10

Why might a middle ear infection cause xerostomia?

Answer 10

The 7th cranial nerve runs through the middle ear

Question 11

How is salivary secretion regulated?

Answer 11

Primarily neural control (autonomic)
Parasympathetic is the main driver
Sympathetic also stimulates small amounts of secretion but also causes vasoconstriction

Question 12

What are the three phases of swallowing?

Answer 12

Oral preparatory phase, pharyngeal phase, oesophageal phase

Question 13

Describe the main features of oral preparatory phase?

Answer 13

Voluntary
Pushes bolus towards pharynx
Once touches pharyngeal wall turns to pharyngeal phase

Question 14

Describe the main feature of pharyngeal phase?

Answer 14

Involuntary
Soft palate seals off nasopharynx
Pharyngeal constrictors push bolus downwards
Larynx elevates closing epiglottis
Vocal cords addict protecting airway and breathing temporarily ceases
Upper oesophageal sphincter opens

Question 15

Describe the main features of the oesophageal phase?

Answer 15

Involuntary
Upper oesophageal sphincter closes
Peristaltic wave carries bolus downwards into oesophagus

Question 16

What is the neural control of swallowing and gag reflex?

Answer 16

Mechanisms receptors in pharyngeal wall
To
Glossopharyngeal nerve (sensory)
To
Medulla
To 
vagus nerve (motor)
To
Pharyngeal constrictors

Question 17

Why do young babies gag on food?

Answer 17

Reflex sits more anterior in mouth so stimulating front causes gagging