GI Basics Flashcards
What “chemicals” assist in the chemical breakdown of food?
Hydrochloric acid and pepsin
Hydrochloric acid is secreted by _____.
parietal cells
What are the functions of hydrochloric acid?
- solvent that dissolves food
- activates pepsin (to begin protein digestion)
- stimulates duodenal release of other digestive enzymes
- kills bacteria in food
What is the function of pepsin?
digests proteins
Pepsinogen is secreted by ____.
chief cells
Which 3 hormones stimulate the parietal cells to secrete hydrochloric acid?
- gastrin
- histamine
- acetylcholine
What is the function of gastrin?
stimulate stomach acid secretion and motility
____ cells secrete gastrin which causes _____ cells to secrete ________.
- G cells
- Enterochromaffin-like cells
- histamine
What is the function of histamine?
stimulate the parietal cells to secrete HCl in response to gastrin
What is the function of acetylcholine?
directly stimulate the parietal cells to secrete HCl
Parasympathetic system (primarily vagus nerve!)
What is the function of somatostatin?
act as negative feedback mechanism to inhibit secretion of gastrin, insulin, glucagon, pancreatic enzymes, and gallbladder contraction
Somatostatin is produced by _____ cells.
Delta (D cells)
What are the main functions of the large intestine?
- Absorb remaining water from undigested food
- Transport undigested food for removal via feces– contains Haustra
- Absorb certain vitamins produced by bacteria (vit. K, biotin)
The large intestine consists of the _____ and the _____.
cecum and colon
What is the function of the duodenum?
responsible for most of the chemical digestion of small intestine and regulates the rate of stomach emptying
Secretin is released by the _____.
Duodenum
What is the function of secretin?
causes the pancreas to release bicarbonate to buffer the acid from the chyme entering the duodenum from the stomach
What are the functions of cholecystokinin (CCK)?
- stimulate release of pancreatic enzymes (trypsin, amylase, lipase)
- increase bicarb release
- stimulate gall bladder contraction and bile release
What is the function of bile release?
help to emulsify fats to make lipase breakdown of fats more effective