BIOL 103 Lecture Notes - Peptic Ulcer, Gastrin, Parietal Cell

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Published on 22 Apr 2013
Department
Course
Biology Lecture #3 Regulation of Digestion System
Topics to be covered regulatory physiology, pioneering discoveries, the peptic ulcer
Stomach
Why aren’t cells in stomach lining hydrolyzed by pepsin nor damaged by hydrochloric acid?
Gastric glands lining stomach produce pepsin in an inactive form called pepsinogen, and this
combined with hydrochloric acid becomes pepsin
Parietal cells that produce HCl don’t accumulate all at once, rather they are formed after
secretion and then the reaction between H+ and Cl- ions that are delivered via pumps that push
against a 1: 3 000 000 gradient (largest gradient that must be overcome inside the human body)
Cells that line the stomach produce a mucous that has a pH of 6 that protects against the acid
Regulation of Digestion
Nervous system has two main functions
Control of muscular and glandular activity by local nerves
Regulation by the brain
Hormones
Secreted mainly be cells that are in the epithelium of the stomach and small intestine that tend
to directly affect those organs
Gastrin
secreted by stomach in response to a meal that stimulates muscle contraction and acid
production, returns to stomach via blood
Secretin and CCK
secreted by movement of acidic chime into small intestine, stimulates secretion of
digestive enzymes and bicarbonate from pancreas
stimulates the contraction of gallbladder to release bile
food particles lead to release of gastrin which increases the acidity of the stomach, which
then leads to the release of secretin and feedbacks and blocks gastrin
cystic fibrosis , recessive disease that causes disruption in a transporter protein, CFTR
pathology associated with the defective protein is that the secretion of mucous is thick
and sticky, and therefore has much effect on body such as not being able to clear the
mucous
mucous blocks the ducts from the stomach down into the small intestine and blocks
enzymes from reaching their destinations, resulting in symptoms of malnourishment
patients therefore have to be on antibiotics for much of life
Target cells located in the pancreas and the gallbladder
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Document Summary

Biology lecture #3 regulation of digestion system. Topics to be covered regulatory physiology, pioneering discoveries, the peptic ulcer. Gastric glands lining stomach produce pepsin in an inactive form called pepsinogen, and this combined with hydrochloric acid becomes pepsin. Cells that line the stomach produce a mucous that has a ph of 6 that protects against the acid. Control of muscular and glandular activity by local nerves. Secreted mainly be cells that are in the epithelium of the stomach and small intestine that tend to directly affect those organs. Gastrin secreted by stomach in response to a meal that stimulates muscle contraction and acid production, returns to stomach via blood. Pathology associated with the defective protein is that the secretion of mucous is thick and sticky, and therefore has much effect on body such as not being able to clear the mucous.

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