Week 1.5 - Upper Respiratory Tract Structure and Function

Question 1

What are the 3 salivary glands in the mouth?

Answer 1

parotid - largest
sublingual
submandibular

Question 2

What is saliva made up of?

Answer 2

• 99% water
• mucins
• alpha amylase
• elecrtrolytes
• lysozome

Question 3

What are mucins?

Answer 3

glycoproteins that are secreted and when mixed with water become mucus

Question 4

What do the salivary gland and duct secrete?

Answer 4

gland has serous and mucus cells.
- serous cells form alpha amylase and lysozomes.
- mucus secrete mucin

Question 5

What controls salivary secretion?

Answer 5

sympathetic and parasympathetic but they both stimulate secretion

Question 6

What form of saliva is secreted by parasympathetic control and which nerves?

Answer 6

comes from facial (7th) and glossopharyngeal (9th) nerves. watery saliva.

Question 7

What form of saliva is secreted by sympathetic control? be specific

Answer 7

• small volume of viscous secretion.
• alpha adrenoreceptors stimulated releasing high mucus content.
• beta adrenorecentprs stimulated releasing high amylase content.

Question 8

How do pressure receptors control saliva secretion?

Answer 8

pressure receptors and chemoreceptors in mouth wall and tongue activate facial and glossopharyngeal activation - secrete saliva

Question 9

What is unique about a baby’s oesophagus?

Answer 9

haven’t fully developed upper oesophageal sphincter, so regurgitate milk often. if persists in adults, GORD may occur

Question 10

What are the phases of swallowing?

Answer 10

• oral phase
• pharyngeal phase
• oesophageal phase

Question 11

What occurs in the oral phase?

Answer 11

voluntary - bolus pushed to back of mouth by tongue.

Question 12

What occurs in the pharyngeal phase?

Answer 12

• pharyngeal muscles contract to push back bolus - involuntary.
• coordinated with swallowing centre in medulla to inhibit respiratory centre while swallowing occurs
• UOS relaxes and epiglottis folds back to prevent food entering larynx.

Question 13

What happens in the oesophageal phase?

Answer 13

peristaltic waves move bolus down in 10 seconds. LOS relaxes as bolus approaches

Question 14

How does the volume and pressure of the stomach change?

Answer 14

from 50ml to 1500ml without change in pressure, due to folds called rugae

Question 15

What are gastric pits?

Answer 15

indentations in stomach wall to allow entrance of gastric glands

Question 16

What are electrolytes in the saliva responsible for?

Answer 16

controlling tonicity and pH