105b stomach and intestines histo

Question 1

what are the folds inside the stomach when it’s empty called?

Answer 1

rugae - due to contraction of muscularis mucosae

Question 2

3 general regions of the stomach - top to bottom

Answer 2

cardiac
fundic
pyloric

Question 3

how many muscles layers are in the stomach muscularis externa?

Answer 3

3 - inner oblique, middle circular, outer linear

churning motion

Question 4

what is the functional gland of the stomach?

Answer 4

gastric glands - mostly in fundic later

Question 5

cell types of the gastric glands (top to bottom) and function

Answer 5

surface mucous cells (washed out, secrete mucous which coats surface and protects cells via mucinogen granules on apical side)
neck mucous cells (different type of mucous)
parietal cells (pink cells, secrete intrinsic factor (B12) + HCl, large pyramidal cells with many mito, extensive network)
chief cells (dark stain, secrete pepsinogen) 
enteroendocrine cells (hormones secretion at basal surface)

Question 6

regional difference in glands for the stomach - cardiac/pyloric vs fundic

Answer 6

fundic more parietal and chief cells

cardiac/pyloric more mucous cells with deeper pits

Question 7

where are new are new gastric epithelial cells made?

Answer 7

isthmus - neck of gastric gland

Question 8

what are the specialized structures in the intestine?

Answer 8

plicae circularis (mucose + submucosa)
villi (core has lamina propria with vessels and lacteal)
microvilli (part of enterocytes)
glands/crypts - invaginations

Question 9

brunner’s gland - location, function

Answer 9

in duodenal submucosa

secrete alkaline mucus

Question 10

intestinal absorptive cell

Answer 10

simple columnar epithelial
microvilli (actin-bundle scaffold) at apical side
tight junctions seal off cell

Question 11

lipid absorption in intestine

Answer 11

1) micelles w/ FFA (from lipases) enter via brush border
2) FFA re-esterified to make triglycerides and cholesteryl esters
3) combined with apo-lipoproteins to make lipoproteins (chylomicrons)
4) chylomicrons secreted to lacteals and capillaries

Question 12

protein absorption

Answer 12

1) pepsin (from chief cells) breaks proteins into polypeptides
2) polypeptides break down into aa’s via pancreatic proteases
3) aa enter via enterocyctes via carrier in brush border
4) aa’s used to build proteins or exit basolater membrane