The stomach

Created by

mayesha

Cards (9)

how is food kept in the stomach?
food enters the stomach and is kept there by the contraction of 2 sphincters, or rings of muscles
what is the volume of the stomach?
about 2dm $^3$
how long does the food stay in the stomach?
food may stay there for several hours
how does the food in the stomach mix with gastric juice?
the stomach wall muscles contract rhythmically and mix the food with gastric juice secreted by glands in the stomach wall
where is gastric juice secreted from?
its secreted from glands in depressions in the mucosa, called gastric pits
what does gastric juice contain?
peptidases, secreted by zymogen, or chief cells, at the base of the gastric pit - pepsinogen, an inactive enzyme, is secreted and activated by H $^+$ ions to pepsin, an endopeptidase which hydrolyses protein to polypeptides
hydrochloric acid, secreted by oxyntic cells - it lowers the pH of the stomach contents to about pH2, the optimum pH for the enzymes, and kills most bacteria in the food
mucus, secreted by goblet cells, at the top of the gastric pit - mucus forms a lining which protects the stomach wall from the enzymes and lubricates the food
what are the layers of the stomach wall?
mucosa (has large folds called rugae)
submucosa
circular muscle
oblique muscles (allow extra contractions)
longitudinal muscle
serosa
what is the pain caused when stomach contents move up into the oesophagus?
the pain caused by the acids on the oesophagus wall is described as heartburn
what is this an image of?
the structure of the gastric pit