Nourani: Intro to the GI system Flashcards
3 phases of gastric acid secretion
- cephalic phase
- gastric phase
- intestinal phase
Mental process that results from sensing food and starts gastric secretion of pepsin and HCl
cephalic phase
Driven by nutrients that directly stimulate the G cell to release Gastrin
gastric phase
Gastrin stimulates this cell
parietal cell
Main cells of the stomach
G cell
Parietal cell
Chief cell
What do G cells secrete?
gastrin
What do parietal cells secrete?
HCl
What do chief cells secrete?
pepsinogen and gastric lipase
Protein digestion begins with this enzyme
pepsinogen
What protects the stomach from digestion?
A mucus layer
Chyme stimulates the duodenum to release these two enzymes which stimulate the pancreas and gallbladder to release bicarbonate, proteases, and bile
secretin, CCK
Most digestion and absorption occurs here
small intestine
3 parts of the small intestine
Duodenum
Jejunum
Ileum
Nutrients are absorbed into the (blank) if they are water soluble, and into the (blank) if they are fat soluble.
blood; lymph
Little digestion occurs here
large intestine
Things that occur in the large intestine
Water absorption
Bacteria break down fiber and produce Vit K
Feces formation
Increase in the motility of the colon in response to stretch in the stomach
Gastro-colic reflex
Four major organs that connect to the gut tube
- salivary glands
- liver
- pancreas
- gallbladder
5th taste bud? What AA is being sensed?
umami; glutamate
Two enzymes in saliva that begin digestion
Salivary amylase: starch breakdown
Salivary lipase: fat digestion (minimal)
2 phases of swallowing: voluntary and autonomic
oropharyngeal phase (voluntary) esophageal phase (autonomic)
What does stomach acid do?
Activates digestive enzymes
Digestion of dietary protein
Assists in calcium absorption
Makes dietary minerals soluble for absorption
