M20: Large Intestine and Regulation Flashcards
sigmoid colon
right colic flexure, left colic flexure
teniae coli
thickened regions of longitudinal muscle
creates pockets (haustra)
omental appendicies
small lipid filled pouches, attached to teniae coli
gastroileal reflex
stomach full - gastrin relased via g cells, relaxes ilecocecal sphincter
haustral churning
haustrum fills, once full, contracts to move
mass peristalsis triggered by gastrocolic reflex
indoles, skatoles are broken down pr - craete odour
bacteria prodice vit B and K
after 3-10 hours, 90% water removed and chyme is feces. 30% of feces weight is actually bacteria
phases of digestion
- CEPHALIC
- GASTRIC
- neural and hormonal mechanisms - INTESTINAL PHASE
- limits how much comes from stomach to control speed of digestion
cephalic phase
neural control
- sensory recpetors
- stim salivation (VII nd IX nerves)
- vagus stim gastric juices in stomach
gastric phase
increased secretion of gastric juices and motility
- neural regulation via feeback loop
- stretch receptors trigger juice production
hormonal regulation
- gastrin causes
constriction of lower esophageal spinch
increses stomach motility
relaxes pylorioc spinc
incrases gastric juices
- when pH decreases, gastin lowers
intestinal phase
inhibits hastric emptying, encourages digestion of foods
neural regulation - feedback loop
- stretch receptors in duodenum sense stretch - ENTEROGASTRIC REFLEX
- signal to medulla oblong. to inhibit PNS and increase SNS nerves to stomach
- gastric motility inhibited, increasesd contraction of pylorci schpinctor
hormonal reg - feedback loop
SECRETIN
- stim. release of pancreatic juice
- decrease gastric secretions
CCK
- stimulates release of pancreatic juice (more focus on nutrient breakdown)
- stim contraction of gallbladded
- relaxes sphincter on hepatopancreatic ampulla
- decrease gastric empltying by contraction of plyloric spinchter
