Lecture 3.2: Oral Region and Oesophagus

Question 1

What is Ingestion?

Answer 1

The process of taking food, drink, or another substance into the body by swallowing or absorbing it

Question 2

What is Mastication?
‡

Answer 2

The process by which food is crushed and ground by teeth

Question 3

What is Salivation?

Answer 3

The process of producing saliva in the mouth

Question 4

What is Swallowing?

Answer 4

The process of passing food from the mouth, by way of the pharynx and oesophagus, to the stomach

Question 5

Are the Submandibular Salivary Glands Serous or Mucous? What do they secrete?

Answer 5

• Serous & Mucous
• Secrete various enzymes, including
  Damylase and lysozyme

Question 6

Are the Parotid Salivary Glands Serous or Mucous? What do they secrete?

Answer 6

• Mainly Serous
• Watery secretion rich in enzymes, but
  little mucus
• Secrete D-amylase (stored as
  zymogen granules)

Question 7

Are the Sublingual Salivary Glands Serous or Mucous? What do they secrete?

Answer 7

• Mainly Mucous
• Viscous secretion, no enzymes, lots
  of mucus

Question 8

What Structure do Salivary Glands have?

Answer 8

Compound Tubuloacinar Glands

Question 9

What is the Role of Incisors (teeth) in Mastication?

Answer 9

Cut food

Question 10

What is the Role of Molars (teeth) in Mastication?

Answer 10

Crush food

Question 11

What muscles are involved in Mastication? (4)

Answer 11

• Masseter
• Temporalis
• Medial pterygoid
• Lateral pterygoid

Question 12

What movement does the Masseter control?

Answer 12

Elevation of the mandible

Question 13

What movement does the Temporalis control?

Answer 13

Elevation and retraction of the mandible

Question 14

What movement does the Medial pterygoid control?

Answer 14

Elevation and side-to-side movements of the mandible

Question 15

What movement does the Lateral pterygoid control?

Answer 15

Protrusion and side-to-side movements of the mandible

Question 16

What is the composition of saliva? (4)

Answer 16

• 99.4% water
• 0.2% soluble inorganic substances
• 0.3% soluble organic substances
• 0.1% insoluble substances

Question 17

How much saliva is produced daily?

Answer 17

1.5L

Question 18

What are the functions of saliva?

Answer 18

• Lubricates and wets food
• Starts digestion of carbohydrates (mainly amylase)
• Protects oral environment
• Keeps mucosa moist
• Washes and protects teeth: High Ca2+
  concentration
• Maintains alkaline environment: Neutralises acid
  produced by bacteria
• Contains proteolytic enzymes which contains lysozyme
  which attacks and destroys bacteria)
• Saliva contains significant amounts of secretory
  antibodies called immunoglobulin A, which can
  destroy some microbes in the mouths

Question 19

What is the composition of Acinar Secretion? How do the ion concentrations compare to ECF?

Answer 19

• A fluid isotonic with ECF
• [Na+], [K+] about the same
• [I-] greater
• [Cl-] slightly less
• [HCO3-] about the same
• Plus enzymes

Question 20

What happens during Ductal modification of saliva?

Answer 20

‡* Little change in volume
‡* [Na+] falls
‡* [K+] rises somewhat
‡* [HCO3-] falls when resting and rises dramatically
when stimulated

Question 21

Control of Salivary Secretion: Volume

Answer 21

Controlled by activity of acinar cells

Question 22

Control of Salivary Secretion: Composition

Answer 22

Affected by duct cells

Question 23

Resting Saliva Characteristics

Answer 23

• Highly modified acinar secretion
• Low volume
• Very hypotonic
• Neutral or slightly acid
• Few enzymes

Question 24

Stimulated Saliva Characteristics

Answer 24

• Less modified acinar secretion
• High volume
• Less hypotonic
• More alkaline
• Lots of enzymes

Question 25

Control of Salivary Secretion: Autonomic (Sympathetic) NS Nerve

Answer 25

Superior cervical ganglion

Question 26

Control of Salivary Secretion: Autonomic (Parasympathetic) NS Nerves (2)

Answer 26

• Glossopharyngeal nerve IX: parotid
• Facial nerve VII: sub-mandibular