Mastication, Swallowing and GI Tract Motility

Question 1

What do digestive secretions contain?

Answer 1

Water, electrolytes and organic compounds

Question 2

What is the function of the palate?

Answer 2

separates mouth from nasal passages to allow simultaneous breathing and chewing

Question 3

What is the function of the uvula?

Answer 3

helps seal off nasal passages during swallowing

Question 4

What reflexes mediate mastication?

Answer 4

masseteric and diagastric

Question 5

Is NaCl lower or higher in saliva than it is in the blood?

Answer 5

much lower

Question 6

Is there glucose in the saliva?

Answer 6

No

Question 7

Which cells modify secretion by removing sodium and chlorine ions (but not water, hence diluting saliva)?

Answer 7

duct cells

Question 8

What cells produce primary secretion?

Answer 8

acinus

Question 9

What happens to HC03 content as flow rate increases?

Answer 9

increases

Question 10

What two types of reflex is formation of saliva increased by?

Answer 10

simple (unconditioned) and acquired (conditioned)

Question 11

Which reflex is known as Pavlov’s Dog?

Answer 11

Conditioned/Acquired

Question 12

What are simple reflexes activated by?

Answer 12

real food

Question 13

What are acquired reflexes activated by?

Answer 13

thoughts about food, smell, sight etc

Question 14

Which type of reflexes are sent to the cerebral cortex?

Answer 14

acquired

Question 15

Which cranial nerves are involved in parasympathetic stimulation causing large volume of watery, enzyme rich saliva?

Answer 15

glossopharyngeal, facial

Question 16

What causes a small volume of thick mucus rich saliva to be produced?

Answer 16

sympathetic stimulation

Question 17

Which receptors mediate parasympathetic stimulation causing the increased saliva secretion?

Answer 17

M3

Question 18

Which receptors mediate sympathetic stimulation causing decreased saliva secretion?

Answer 18

B1

Question 19

What are the 2 phases of movement of food?

Answer 19

oropharyngeal and oesophageal

Question 20

What type of muscle is the peristalsis wave mediated by?

Answer 20

skeletal in upper oesophagus, smooth distally

Question 21

What is secreted by the oesophagus?

Answer 21

entirely mucus for lubrication and protection

Question 22

What is relaxation of the stomach driven by?

Answer 22

vagus nerve (to accommodate food from the oesophagus)

Question 23

Does much absorption occur in stomach?

Answer 23

No

Question 24

Where is gastric juice secreted from?

Answer 24

gastric pits

Question 25

What kind of cells establish a basal electrical rhythm and where does it spread?

Answer 25

pacemaker cells, from fundus towards pyloric sphincter

Question 26

What determines escape of chyme through pyloric sphincter?

Answer 26

antral wave strength

Question 27

What factors govern the strength of the antral wave?

Answer 27

``` gastric factors (rate of emptying, distension - increases motility - and consistency of chyme) Duodenal factors (neuronal response, hormonal response, stimuli such as fat, acid, hypertonicity and distension) ```