41.3 Digestion in the Stomach

Question 1

Stomach

Answer 1

below the diaphragm -primarily for storing food and continuing digestion -secretes gastric juice

Question 2

gastric juice

Answer 2

digestive fluid mixed with the food by a churning action -to make chyme (the mix of digestive juice and food) 1-hydrochloric acid (HCl) 2- pepsin

Question 3

chyme

Answer 3

the mix of digestive juice and food) in the stomach

Question 4

HCl

Answer 4

-pH 2 -disrupts the extracellular matrix that binds cells together in meat and plants -denatures proteins in food -increases exposure of peptide bonds (tha tare attacked by pepsin )

Question 5

pepsin

Answer 5

-a protease–protein digesting enzyme -breaks peptide bonds to cleave proteins into smaller polypeptides -> further digestion happens in small intestine

Question 6

why doesn’t gastric acid destroy stomach cells?

Answer 6

the ingredients of the gastric juice are kept inactive until that are released into the lumen (cavity) of the stomach -mucus -cell division adds new epithelial layer every 3 days

Question 7

*gastric gland components

Answer 7

-PARIETAL CELLS: secrete H+ and Cl- (combine to make HCl) -CHIEF CELLS: release pepsinogen. Hlc converts it to pepsin -MUCUS CELLS: secrete mucus-protect stomach cells

Question 8

parietal cells

Answer 8

pumps H into lumen in high concentrations (ATP) -chloride diffuse into lumen with membrane channels -they combine -> HCl

Question 9

chief cells

Answer 9

release pepsinogen -HCl converts it to pepsin by clipping it to expose active site -the rest of it is converted by a 2nd chemical process (positive feedback)

Question 10

Mucus cels

Answer 10

secrete mucus- glycoproteins, cells, salts, water

Question 11

gastric ulcers

Answer 11

damaged areas of stomach lining -acid tolerant bacteria can cause them -treated with antibiotics

Question 12

churning

Answer 12

makes chyme

Question 13

heart burn

Answer 13

when chyme back flows -irritating esophagus