de Lisle: Secretion, biophysiology of GI

Question 1

why are parietal cells more eosinophilic?

Answer 1

more mitochondria

Question 2

why are chief cells more basophilic?

Answer 2

more rough ER = more RNA = for transport of pesinogen

Question 3

Where is secretory surface of partietal cell?

Answer 3

Canaliculus

Question 4

are there chief cells in pyloric stomach?

Answer 4

no just body/fundus

Question 5

Antrum and pyloric have what sort of cells?

Answer 5

Enteroendocrine cells: G and D cells.

Question 6

Somatostatin blocks what portion of the Gi cascade?

Answer 6

Adenylate cyclase

Question 7

Acetylcholine and Gastrin act through

Answer 7

PLC/IP3 and Ca cascade

Question 8

CCKb has higher affinity for

Answer 8

Gastrin

Question 9

Calcium and cyclate= synergistic affect exmaple

Answer 9

gastrin triggers Ca cascade also stimulate G cells in pyloric region to stimulate ECL cells to stimulate release Histamine which acts through Adenylate cyclase

Question 10

Where is the H/ATPase on the cell?

Answer 10

Apical surface

Question 11

parietal cell inhibitors?

Answer 11

Somatostatin
PGE2
CCK

Question 12

PACAP (pituitary adenylate cyclase-activating peptide) stimulates ________ release from ECL cells ( in the body/fundus) when stimulates by _______ in the G cells of the pyloric region

Answer 12

histamine,

gastrin

Question 13

HKatapse on the apical side of the parietal cell.

Pumps H out to the lumen, HCO3 pumps passes into the blood stream and Cl into the cell to balance the charge difference

Cl- exits through Chloride channel to form HCl.

What causes the alkaline tide?

Answer 13

HCO3 moving basolaterally into the blood as H moves to the lumen
zzzzzz

Question 14

What enzyme is critical in producing H+ and HCO3- from CO2 and H2O and can be found in parietal cells of the stomach body, pancreatic and liver bile ducts, Brunner’s glands of the submucosa, and intestinal crypts?

Answer 14

Carbonic Anhydrase

Question 15

In an inactive parietal cells, where are the H, K/ATPase’s located?

Answer 15

in the tubulovesicle

Question 16

In the stimulated state, core actin filaments have vast rearrangements causing the canalicular space to fill with?

Answer 16

Microvilli

Question 17

if you stained for actin in a stimulated parietal cell, you would see

Answer 17

super bright green staining

Question 18

Why doesn’t the proton pump work when it’s in the tubulovesicle (not endocytosed with the canalliculi

Answer 18

the proton would be pumped into the tubulo vesicle and as it’s endocytosed the proton pump faces the lumen

Question 19

What drug irreversibly inactivates the proton pump and could allow C Diff proliferation because of lack of acid.

Answer 19

omeprazole, lansoprazole (PPIs)

Question 20

Where is protein first digested?

Answer 20

In the stomach by pepsin (pepsinogen released by chief cells)

Question 21

Where does the alkaline tide from parietal cells circulate to?

Answer 21

goes through capillaries to epithelium to protect.

Question 22

if the epithelia of the stomach are damaged what happens?

Answer 22

The living cells migrate up to the epithlia short term before cell division occurrs.

Question 23

what epithelia over peyer’s pataches in the ileum?

Answer 23

squamous amongst ileal simple columnar epithelia

Question 24

is M cell an antigen presenting cell?

Answer 24

no, just endocytoses.

Doesn’t digest anything,

Question 25

what’s the major Ig of the body and where is it transported usually?

Answer 25

IgA, mucosal surfaces.