Topic 9 Gastrointestinal system_6 Gallbladder/Lg intestine Flashcards
A pear-shaped organ sitting in the posterior surface of the liver
Stores and concentrates bile
Released into the sm intestine via the common bile duct
Gallbladder
Substance
> a yellow/brown/ olive liquid
> made of hepatocytes
> collects into larger and larger vessels
Function > emulsification (breakdown) of fats
Bile
Food enters here from the sm intestine (ileum) though the ileocecal valve/ sphincter
Large intestine
what are the 4 regions of the lg intestine?
Cecum
colon
rectum
anal canal
Its Functions are completion of absorption (mostly water), vitamin K production, formation and elimination of feces
Large intestine
*vitamin K - blood clot process
Large intestine contd
> sm pouch attached to the ileocecal valver
> the appendix attaches there
> contents from it move into the colon
Cecum
Part of the large intestine that is divided into 4 portions
*regular peristalsis occurs but more slowly
Colon
4 portions of the colon
> ascending (to the hepatic flexure (bend)
transverse (to the splenic flexure)
descending (to the left iliac crest)
sigmoid (to the rectum at S3)
Colon process…
> as food accumulates in the ascending colon
> haustra (pouches along colon) fill up/distend
> stimulates smooth muscle contraction
> & food moves into the next haustra
x
Travels inferiorly to the canal
Rectum
Terminal (last ) portion of the anal canal
- elimination control:
> internal (involuntary control)
> external (voluntary control) anal sphincter
Anal canal
Term
Distension of the rectum ultimately gives the urge to go and relaxes the internal anal sphincter
The defecation reflex
There are 2 division of teh GI tract name them
> Upper GI - mouth, pharynx, esophagus, stomach, duodenum (sm intestine)
Lower GI - most of the intestines and the anus
What are the 3 overlapping phases of the control process of digestion
Cephalic
Gastric
Intestinal
Overlapping digestion phases…
The thought, smell, sight, initial taste of food activates the NS
Salivary and gastric glands are stimulated to prepare the mouth and stomach for digestion
Cephalic phase
Overlapping process of digestion… phase type?
Once food reaches the stomach > changes happen
> stretch receptors are stimulated by the change in the stomach shape
> chemo receptors are stimulated by the change in stomach pH
Cause these changes
> food in stomach changes the homeostasis of the stomach
> increase peristalsis and gastric juice production
> stimulate gastrin release
> small amounts of chyme pass through the pyloric sphincter into the duodenum
food leaving the stomach decreases the volume and removes some of the stimulus from stretch receptors
food leaving the stomach allows the stomach to become more acidic
decrease stretch receptor stimulation and normalizing pH removes some of the stimulus for gastrin release
Gastric phase
Overlapping process of digestion… phase type?
> chyme in the duodenum causes enteroendocrine cells to release hormones:
> cholecystokinin (CCK)
> secretin
Intestinal phase
The hormones of cholecystokinin (CCK) and secretin released during the intestinal phase of digestion cause what type of changes? (4)
> stimulates the gallbladder to release bile into the duodenum (CCK)
decrease gastric juice production (CCK/secretin)
slow food coming through the pyloric valve (CCK/secretin)
increase pancreatic juice secretion (CCK/secretin)
