Glands, cells, hormones Flashcards Preview

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Flashcards in Glands, cells, hormones Deck (27):
1

gastric glands

mucous cells
chief cells
parietal cells
stem cells
gastroendocrine cells

2

in the gastric pit, where are the surface mucous cells located?

in the "pit" i.e opening of the pit, area

3

in the gastric pit, where are parietal cells located?

in the neck region

this region is known as the "isthmus"

4

in the gastric pit, what cells are in the body?

chief cells predominate followed by enteroendocrine cells,

5

Mucous cells of the fundus

what is their mucous made from

two types: mucous neck cells and the mucous surface cells

neck cells are located in the opening of the pit

mucous is made from 95% water and % mucins




mucous layer traps bicard inons and neutralixes microenvironment adjacnte to the apical region of the surface mucous cells to an alkaline pH

6

chief cells

predominate in the lower third of gastric pit

no present in cardiac region, not found in pyloric antrum


in apical regions, contains pepsinogen secretory granules.

pepsinogen is a proenzyme

converted in acidic environment to a proteolytic enzyme

exocytosis of pepsinogen is rapid, stimulated by feeding

7

gastric glands of the fundus region contain two major cells

chief cells (peptic) and parietal cells

8

Parietal cells

also called oxynitic cells. secrete HCL and intrinsic factor.

after stimulation, vesicles fuse with apical membrane.

carbonic anhydrase AND "H, K-ATPase" is localized into microvilli projecting into the lumen of the intracellular canaliculus.

9

What receptors are on the bottom of a parietal cell?

histamine receptor, ACh receptor, and gastrin receptor

10

pepsinogen can be released by stimulation of what neurotransmitter

ACh

11

autoimmune gastritis

caused by antibodies to H,K-ATPase, in the parietal cell, and intrinsic factor


destruction of parietal cells causes a reduction in HCL ("achlorhydria") and a lock of synthesis of intrinsic factor

result: B vit 12 deficiency disrupts formation of red blood cells in bone marrow

12

a patient is achlorhydriia and anemic, what is a possible problem? what would be suitable treatment?

she has autoimmune gastritis, requiing Vit B 12 supplimentation

13

how HCL secretion works in parietal cells

parasympathetic stimulation via ACh and the peptide gastrin, produced by enteroendorcrine cells of the pyloric antrum, stimulate parietal cells to secrete HCL

ACh stimulate also stimulates gastrin release

14

gastric juice contains two protective layers

an alkaline mucosa and an acidic gel (HCL and PEPSIN).

15

where does helicobacter pylori reside and under what conditions?

in the pyloric antrum region, under both the alkaline conditions of the mucosal gel and the acidic environment above it.

16

h pylori produces what

is is associated with peptic ulcers

17

peptide hormones produced by the GI endocrine cells have the following functions

regulation of water, electrolyte metabolism, and enzyme secretion

regulation of GI motility and mucosal growth

stimulation of the release of other peptide hormones

18

Secretin

released by cells in the duodenal glands of lieberkuhn when gastric content enters the duodenum


secretin stimulates pancreatic and duodenal bicarb (from brunners glands)

19

brunners glands release ___ from stimulation by

bicarbonate from stimulation by secretin

20

____ together with CCK stimulates growth of exocrine pancreas

secretin

21

secretin stimulates ______ cells to release a proteolytic enzyme, and inhibits _____ release and reduce HCL

chief cells, gastrin release

22

Gastrin

produced by G cells located in pyloric antrum

there are three forms

main function is to stimulate function of HCL from parietal cells

can also activate CCK to stimulate gallbladder contraction

23

CCK

peptide hormone

produced in duodenum

stimulates gallbladder contraction and relaxation of sphincter of Oddi when proteins and fat rich chyme enters duodenum

24

GIP

glucose dependent insulinotropic peptide

formally called gastric inhibitory peptide, produced by duodenum, stimulates insulin release when glucose detected in small intestines

25

how do you distinguish pyloric glands from cardiac and gastric glands

they're much more tortuous
simple tubular and branched

26

muscularis externa of stomach

three layers, inner most circular, internal oblique, longitudinal directions


27

distal pyloric antrum

where annular pyloric spinchter forms