GI 3

Question 1

Cephalic phase

Answer 1

Increased parasympathetic output from medulla to salivary glands and the ENS

Question 2

Mechanical digestion

Answer 2

• chewing by teeth
• tongue and lips help
• joined by flood of saliva

Question 3

3 pairs of salivary glands

Answer 3

parotid, submandibular, sublingual

Question 4

4 functions of saliva

Answer 4

• soften and moisten food
• digestion of carbs (amylase)
• dissolve foods (taste)
• defense (lysozyme)

Question 5

Saliva is an exocrine secretions which means…

Answer 5

It is released onto epithelium instead of bloodstream

Question 6

How much saliva is ?released? per day?

Answer 6

1.5L/day

Question 7

Saliva is __% water and __% solutes

Answer 7

99.5% water, 0.5% solutes

Question 8

acini

Answer 8

secretory cells found in clusters

Question 9

parotid glands

Answer 9

watery solution with amylase

Question 10

submandibular glands

Answer 10

similar to parotid plus some mucus

Question 11

sublingual glands

Answer 11

mainly mucus

Question 12

Saliva secretion is primarily under _________ control.

Answer 12

parasympathetic

Question 13

serous cells

Answer 13

secrete watery fluids; no mucus really

Question 14

deglutition

Answer 14

reflex that pushes a bolus of food or liquid into the esophagus

Question 15

somatic motor outputs

Answer 15

to pharynx and upper esophagus

Question 16

autonomic motor outputs

Answer 16

to the lower esophagus

Question 17

Explain process of swallowing

Answer 17

• soft palate elevates and closes nasopharynx
• larynx moves up and forward, closing trachea
• upper esophageal sphincter opens

Question 18

Food moving downward into the esophagus is propelled by…and aided by…

Answer 18

peristaltic waves, gravity

Question 19

epiglottis

Answer 19

helps keep swallowed material out of airways

Question 20

gastroesophageal reflux disease (heartburn)

Answer 20

-negative intrapleural pressure during inspiration can cause esophagus to expand, drawing gastric acid and pepsin from the stomach

Question 21

3 general functions of stomach

Answer 21

-storage, digestion, defense

Question 22

receptive relaxation

Answer 22

upon swallowing food, parasympathetic neurons to ENS cause funds to relax

Question 23

propulsion

Answer 23

moving chyme towards pylorus

Question 24

retropulsion

Answer 24

when chyme is moved back to the body (from duodenum to stomach)

Question 25

G cells

Answer 25

release gastrin in response to amino acids, peptides, and distension during short reflex

Question 26

ENS and gastrin production

Answer 26

ENS stimulates gastrin production during long reflex

Question 27

G-cells

Answer 27

stimulate gastric acid secretion

Question 28

direct vs indirect gastric acid secretion secretion

Answer 28

direct: directly from parietal cells
indirect: stimulates histamine release from enterochromaffin-like cells, stimulating parietal cells

Question 29

parietal cells

Answer 29

produce 1-3L of historic acid (HCl) daily with a pH as low as 1

Question 30

gastric acid functions

Answer 30

• stimulate release of pepsinogen and cleaves it to pepsin
• denatures proteins
• kills bacteria and other microorganisms
• inactivates amylase from saliva
• stimulate D cells

Question 31

pepsin

Answer 31

digests proteins