structure of GI tract ad motility Flashcards
(17 cards)
GI tract wall
serosa -> muscularis extema -> submucosa -> mucosa
muscularis extema
myenteric plexus
facilitate segmentation and peristalsis
submucosa
submucosal plexus
mucosa
goblet cell: secrete mucus
gland secrete digestive substances
enteric nervous system
myenteric plexus: control motility
submucosal plexus: control secretion
extrinsic nerve
sympathetic: inhibit digestion
parasympathetic: stimulate digestion
peristalsis
adjacent segment
segmentation
non adjacent segment
back-n-forth movement
Ingestion: swallowing reflex
controlled by swallowing centre
tongue
skeletal muscle fibres
taste buds
deglutition (swallowing)
- buccal phase: voluntary
- pharyngeal-esophageal plase: involuntary
- peristalsis
- gastroesophageal sphincter relax -> food enter stomache
stomache: gastric pits
gastric juice:
mucous neck cell: mucus
parietal cell: B12 and HCl
chief cell: pepsinogen
hormones
motor function of stomach
reservoir: receptive relaxation
mixing and grinding of food
gastric emptying: regulate the rate of chyme entering duodenum
small intestine
duodenum: receive bile/ pancreatic enzyme
jejunum
lleum: paneth cell -> release antimicrobial agents
brush broader enzyme: complete digestion
large intestine
content illeum pass into cecum through ileocecal valve: regulate the rate, prevent backflow of colonic contents
large intestine: function
absorption of water, vitamin and salt
temporary storage of undigested material
defecation: mechanism
feces distend rectum and stimulate stretch receptor
-> send signals to spinal cord through nerve fibre:
- spinal reflex: efferent fibre stimulate the contraction of rectum and sigmoid colon, and relaxation of internal sphincter
inhibition of voluntary motor neuron: relax the external sphincter
