5.1. Overview of the Mouth / Oral Cavity

Question 1

What is the function of Chewing (Mastication)?

Answer 1

To physically break the foodstuff down into smaller portions

Question 2

What is the physically broken-down Foodstuff known as?

Answer 2

A Bolus

Question 3

What are the 2 controls of Chewing (Mastication)?

Answer 3

1. Voluntary

2. By Reflex

Question 4

Which nerve controls the Muscles of Mastication?

Answer 4

The Mandibular Branch of the Trigeminal Nerve (Cranial Nerve V3)

Question 5

How is Mastication initiated by Reflex?

Answer 5

1. Contraction of the Jaw Muscles increases the Pressure of Foodstuff against the Gums, Hard Palate and Tongue
2. This activates Mechanoreceptors which causes the inhibition of the Jaw Muscles
3. This reduces the pressure on these structures, which leads to contraction

Question 6

What are the contents of Saliva?

Answer 6

1. Water
2. Mucins
3. Alpha-Amylase
4. Electrolytes
5. Lysosomes

Question 7

Which content of Saliva is the most abundant?

Answer 7

Water - This constitutes 99% of the secretory fluid

Question 8

What does the Water, secreted from the Salivary Glands, do?

Answer 8

It Soften, Moistens, and Dilutes the Foodstuff Particles

Question 9

What is the Major Protein Component of Saliva?

Answer 9

Mucsins

Question 10

What do the Mucins combine with?

Answer 10

Water

Question 11

What does the Mucin-Water combination produce?

Answer 11

Mucous

Question 12

What is the Function of the Salivary Mucous?

Answer 12

It is a Viscous Solution used for Lubrication

Question 13

What is the function of the Alpha-Amylase in the Saliva?

Answer 13

It catalyses the break-down of Polysaccharides into Disaccharides

Question 14

What is the function of the Electrolytes?

Answer 14

To maintain the pH and Tonicity

Question 15

What is the function of the Lysosomes?

Answer 15

These are Bacteriocidal

Question 16

How are the Lysosomes Bacteriocidal?

Answer 16

These cleave the Polysaccharide component of the Bacterial Cell Wall

Question 17

What are the 3 major Glands Saliva is secreted from?

Answer 17

1. The Parotid Gland
2. The Submandibular Gland
3. The Sublingual Gland

Question 18

Which Nervous System stimulates Saliva Secretion?

Answer 18

The Autonomic Nervous System (Sympathetic and Parasympathetic NS)

Question 19

Which Branch of the Autonomic Nervous System stimulates the secretion of Saliva?

Answer 19

Trick Question:

Both of them do

Question 20

What type of Saliva does the Parasympathetic Stimulation cause?

Answer 20

Profuse Watery Saliva

Question 21

What type of Saliva does the Sympathetic Stimulation cause?

Answer 21

Small Volume thick Saliva ( remember when nervous mouth dry and thick saliva)

Question 22

Which Parasympathetic Nerves innervate the Salivary Glands?

Answer 22

1. The Facial Nerve (Cranial Nerve VII -7)

2. The Glossopharyngeal Nerve (Cranial Nerve IX -9)

Question 23

What are the contents of the Viscous (thick) Salivary Secretions (innervated by the Sympathetic Nervous System)?

Answer 23

1. High Mucous Content

2. High Amylase Content

Question 24

What stimulates the release of the High Mucous Content of the Viscous Saliva?

Answer 24

The Alpha-1-Adrenoreceptors

Question 25

What stimulates the release of the High Amylase Content of the Viscous Saliva?

Answer 25

The Beta-2-Adrenoreceptors

Question 26

What is the Reflex Control of Salivation?

Answer 26

Stimulation which will automatically occur with the presence of food in the Mouth.

Question 27

How does the Reflex Control of Salivation work?

Answer 27

The Presence of food in the Mouth activates Chemoreceptors and Pressure Receptors in the Wall of the Mouth and Tongue, initiating the response