GI 4 Flashcards
Active transport of free H+ into the stomach lumen in exchange for K+ increases…
pH, drawing in H2O and CO2 in the cell
What can inhibit acid secretion?
intestinal hormones
Digestive enzyme secretion is stimulated by…
neural input and acid secretion
ECL-Histamine
activates H2 receptors on parietal cells to stimulate HCl secretion
parietal cell-intrinsic factor
forms a complex with vitamin B12 so it can be absorbed
D cell-somatostatin
- negative feedback for acid secretion
- inhibits pepsinogen release
Music secretion is stimulated by…
parasympathetic input and irritation
HCO3- secretion stimulated by…
parasympathetic input and H+
peptic ulcer
A sore or break in the lining of the stomach or duodenum
What causes peptic ulcers and how can it be treated?
- caused by excessive acid production or bacteria
- treated with non steroidal anti-inflammatory drugs (NSAIDS)
Major cause of peptic ulcers?
bacteria
What is the urea breath test
A test for diagnosing the presence of the ulcer-causing bacterium, H. pylori in the stomach.
Describe intestinal phase
- food, fluids, and secretions enter small intestine
- segmental and peristaltic contractions mix chyme with enzymes and expose nutrients to mucosal epithelium for absorption
What promotes motility?
parasympathetic innervation, gastrin, and cholecystokinin
What inhibits motility?
Sympathetic innervation
villi
increase surface area available for absorption and secrete mucus
crypts
contain hormone and fluid secretory cells and stem cells (secrete ions and water)
lacteals
tranport most fats to the lymph
enterocytes
transport nutrients and ions
Hepatic portal system
The liver contains a variety of enzymes that metabolize drugs and xenobiotics and clear them from blood stream before it can proceed to systemic circulation
Intestinal secretions promote..
digestion
Approximately ____L of secretions enter the lumen of the small intestine.
3.5L (along with 5.5L of food, fluid, and secretions)
~ __L ABSORBED IN DUODENUM AND JEJUNUM
7.5L
