GI 6 Flashcards
Mineral absorption is usually by..
active transport
Transcellular transport is regulated by…
vitamin D3
Fat soluble vitamins are absorbed with…
fats
Water soluble vitamins are absorbed by…
mediated transport
B12 is absorbed in the..
ileum
Most water is absorbed in…
the small intestine
How is Na+ absorbed?
NaK-ATPase pumps it into the ECF
How do water and J+ get absorbed?
they move though paracellular pathways
S cells/secretin
stimulated by acid entering the duodenum from the stomach
-primary role in regulation of pH
How does secretin regulate pH
-stimulates bicarbonate secretion from pancreas and inhibits gastric acid secretion, motility, and emptying
I cells/ cholecystokinin (CCK)
stimulated by presence of fatty acids and amino acids in chyme
- regulates pancreatic enzyme secretion and bile secretion
- inhibits gastric acid production/emptying
K cells
GIP
L cells
GLP-1
Primary endocrine function of GIP and GLP 1
glucose homeostasis
-inhibit gastric acid secretion and motility
the large intestine
store and concentrates fecal matter
~ ___L of chyme proceed through the ileocecal valve
1.5L
gastroileal reflex
food in the stomach causes contraction of ileum
After ions and water is reabsorbed, how much is left to be excreted?
0.1L
Secretion in the large intestine
minimal and primarily consists of mucus from goblet cells
Digestion in large intestine
historically believed that zero digestions occurs
Effects of probiotics?
- reduced depression, anxiety
- increased memory and social behaviour
- increased sensory gating
3 types of motility in the large intestine
- slow peristaltic movement
- haustral rolling or churning
- mass peristalsis
haustal rolling/churning
additional muscle layer, taenia coli, creates pouches called haustra when contracted
mass peristalsis
gastrocolic reflex, stimulated by food in stomach
3 reflexes initiated by distension of the rectum
- peristaltic waves
- relaxation of internal sphincter
- contraction of external sphincter
diarrhea
an increase in the frequency, volume, and fluid content of faces due to increased secretion, reduced absorption, or increased motility
80% of lymphocytes are located in..
the gut
Vomiting centre in the medulla causes what 3 primary responses?
- retrograde contractions in the small intestine and stomach
- contraction of abdominal and inspiratory muscle increasing gastric pressure
- relaxation of esophageal sphincters
