GI Phys 3: Stomach

Question 1

location, function, and secretion of mucous cells and neck cells

Answer 1

located at surface, secrete mucus and bicarb, function is gastroprotection to protect the stomach from itself

Question 2

location of parietal cells

Answer 2

deeper withi nthe pit

Question 3

parietal cells secrete what? what is their function

Answer 3

secrete HCl and intrinsic factor. function related to HCl release is protein digestion and sterilization of environement. for IF, the function is nutrient absorption

Question 4

Chief cells secretion and function

Answer 4

chief cells secrete pepsinogen (a protease). the function is for protein digestion

Question 5

list the 4 important regulatory cells in the stomach

Answer 5

ECL, neurons, D and G cells

Question 6

ECL cells secrete what

Answer 6

histamine

Question 7

function of histamine

Answer 7

important paracrine regulator

Question 8

neurons secrete what

Answer 8

ach

Question 9

G cells secrete what

Answer 9

gastrin

Question 10

d cells secrete

Answer 10

somatostatin which turns off GI activity (suppresses hcl secretion)

Question 11

location of g and d cells

Answer 11

antrum

Question 12

how is acid secretion regulated? (3 pathways)

Answer 12

1) paracrine pathways (histamine)
2) endocrine pathways (gastrin)
3) neuronal pathways (ach)

Question 13

which type of cells are the primary secretory cells of pepsinogen

Answer 13

chief cells. key stimulus = Ach!!!!

Question 14

Pepsinogen to pepsin - process?

Answer 14

chief cells secrete pepsinogen (inactive). Hcl needed for activation. A lower ph is needed to activate pepsin (1-3). once active, pepsin can activate additional molecules.

Question 15

acid secretion is regulated directly through:

Answer 15

prostaglandins, which inhibit signaling through the histamine pathway

Question 16

four key gastric secretions

Answer 16

acid (hcl), pepsinogen, intrinsic factor, mucus

Question 17

3 gastric motility patterns

Answer 17

storing, churning, emptying

Question 18

2 steps in gstric storing/filling

Answer 18

1) receptive relaxation

2) gastric accommodation

Question 19

receptive relxation

Answer 19

mediated by the vagus nerve, initiated by swallowing, relaxation of stomach in anticipation of food (No and VIP)

Question 20

gastric accommodation

Answer 20

mediated by ENS, stoamach relaxes in response to gastric and duodenal filling or stretch (no and vip help)

Question 21

fat stimulates the release of what

Answer 21

cck

Question 22

4 key NT’s involved in emesis

Answer 22

serotonin, dopamine, histamine, ach

serotonin = key NT from gut to sensory neurons in cns