Gastric regulation Flashcards
What is the response when there is thought, sight, taste or smell of food?
the sight/ thought of food: in cerbral cortex. then to hypothalamus and medulla oblongata, then vagus neve
taste/smell hypothalmus and medulla oblongta: through the vagus nerve
What stimulatory events orginate in the stomach?
Stretch receptors go to either local reflexes or vagovagal reflexes
What action occurs as a result of food in the stomach?
G cells releasing gastrin into blood
WHat occurs when there is low pH and parially digested food in duodenum?
anteric gastric released into blood
What decreases the secretion of gastrin?
When pH of stomach is very low or <2
What is the role of the pyloric sphincter?
prevent too much food from going into duo too quickly. Maintains a contraction along with the enteric (systolic contraction) that moves food along
Role of brush border?
break down small things at wall with contact
Where does most digestion and absorption occur in the small intestine?
jejunum
Where is viatmin B12 absorbed?
ileum
What does the duodenum recieve?
chyme, pancreatic juice (contains enzymes for breakdown) and bile (contain salts that break down fats)
What is segmentation?
mixing of enzymes and food particles for break down. mixes chyme with duodenum secretions
What is peristalsis
moves residue throughout digestive tract
WHat is the gastroileal reflex?
it is triggered by food in stomach and relaxes ileoceal nerve to move food easily inot large intestineq
What types of hormones are secreted by the small intestine?
Intestinal juice: water and mucus,
duodenal Brunner’s glabds secrete bicarbionate-rich mucus
enteroendocrine cells secrete secretibn and cholecystokin
What is gastroileal reflex?
It is triggered by food in stomach. It relaxex the ileocecal valve to move residue into large intestinal
What contractions are present in the large intestine?
haustral contractions and mass movements, which are triggered by gastrocolic and duodenocolic reflexes
Describe the defecation reflex pathway?
The large intestine stretches as a results of food moving inside it. This causes the peristalsis and relexation of interal sphincters. The conious thought coments in for the external one.
Where do pnacreatic juices come from?
the pancreatic acini
WHat does the pancreatic juice contain?
water, enzymes, zymogens, and sodium bicarbonate
WHat enzyme facilaites formation of Hcl?
carbonic anhydrase
What zymogens are found in pancreatic juice?
trypsinogen. chymotrpsinogen, procarboxypeptidase
What is enterokinase?
it is a brush border enzyme thta activates trypsinogen to trypsin
What does trypsin activate?
other trypsinogens and pancreatic proteases
Where is bile stored?
live and the gall bladder
