38 - Assessment: GI System Flashcards
paraSNS -cholinergic effect on GI
mainly excitatorry effects on GI
sns - adrenergic effect on GI
inhibitory effect
GI tract nervous system is called…
enteric NS or intrinsic NS
Entreric NS [ENS]
regulates motility + secretin of GI
2 networks:
- -1 Messner plexus (in submucosa)
- -2 Auerbach/Myenteric plexus (bw muscle layers)
Messner plexus
submucosal plexus controls secretion + many sensory fux
Auerbach/Myenteric plexus
major nerve supply to GI tract
-controls mvmt
the ENS receives innervation from ANS, but it ____
functions INDEPENDENTLY of brain + spinal cord
veous blood draining the GI organs empties into ___
the PORTAL VEIN
- then perfuses the liver
- liver cleans the blood of bacteria + toxins
GI tract receives ___% of CO at rest, and
_____% after eating
25-30% of CO at rest
35% or more after eating
bc such a large % of CO perfuses these organs, the GI tract is a major source from which to divert blood flow during exercise, stress, or injury**
appetite center is found in the
hypothalamus
ghrelin
hormone release fr stomach mucosa
-plays role in appetite STIMULATION
leptin
hormone involved in appetite SUPPRESSION
deglutition
swallowing
bw swallows, the esophagus is ______ and the upper esophageal sphincter is _____
esophagus is COLLAPSED,
ues is CLOSED
LES
lower esophageal sphincter
- controls opening of esophagus to stomach
- *important barrier that normally prevents refluc of gastric contents into esophagus
stomach functions
- store food
- mix food w gastric secretions
- empty contents in small boluses into sm.intstns
fundus glands
1 chief cells> secretes pepsinogen
2 parietal cells> secretes HCl, H2O, intrinsic factor
intrinsic factor
promotes B12 (cobalamin) absorption
sm. intstn functions
digestion + absorption
mouth secretions
salivary amylase (starts starch digestn)
stomach secretions
1 HCl (activates pepsinogen to PEPSIN) 2 intrinsic factor (cobalamin absorptn) 3 lipase ( fat diegestn) 4 pepsinogen (protein digestn)
small intestine secretions
1 aminopeptidate + peptidase (protein digestn) 2 amylase (carb digestn) 3 lactase (lactose>glucose+galactose) 4 lipase (fat digestn) 5 maltase (maltose>glucose) 6 sucrase (sucrose>glucose/fructose) 7 enterokinase (trypsinogen to trypsin)
pancreas secretion
1 amylase (starch to disaccharides) 2 chymotrypsin (protein digestn) 3 lipase (fat digestn) 4 trypsinogen (protein digestn)
bile
emulsifies fats
-aids in absorption of fatty acids + fat solbl vitamins
protein digestion begins w ___
release of pepsinogen fr chief cells
- low pH activates pepsinogen into pepsin
- pepsin breaks down protein
lrg intestine functions
- water + electrolyte absorption
- feces
microbes in the _____ contribute to digestion by ____________
microbes in the COLON contribute to digestion by PRODUCING VITAMINS K + B, BREAKING DOWN PROTEINS THAT ARE NOT DIGESTED OR ABSORBED IN SMALL INTESTINES INTO AMINO ACIDS
Valsalva maneuver
“bearing down”
-inspire deeply + hold breath + close airway + contract ab muscles
Valsalva maneuver effect on oxygenation
- reduce venous hrt return
- decr hrt rate
- decr CO
- —–transient drop in BP
Valsalva maneuver
CI
- head injury
- eye surgery
- hrt problems
- hemorrhoids
- ab surgery
- liver cirrhosis w portal hypertension
sinusoids
capillaries bw rows of hepatocytes
-lined w kupferr vells which carry out phagocytic activity (removes bacteria + toxins in blood)
presence of fat in upper duodenum triggers the release of _____
cholecystokinin (CCK)
–causes gallbladder to contract + release bile
pancreas exocrine function
contributes to digestion by production + release of enzymes
pancreas endocrine function
occurs in islet of langerhans B cells> insulin + amylin A cells> glucagon Gamma cells> somatostatin F cells> pancreatic polypeptide
age-related changes
- delayed emptying
- sm. muscle weakness
- redues UES opetning
- incompeten LES
- decr GI motility
***secretion + absorption are less affecrted
aging + constipation
- slower peristalsis
- anorectal dysfunction
- inactivity
- decr dietary fiber
- inadequate fluid intake
- constipating meds
- neurologic, cognitive, metab problems
upper GI series
to ID esophageal stricture, polyps, tumors, hiatal hernias, foreign bodies, + ulcers
lower GI series or barium enema
ID polyps, tumors, lesions
pyrosis
heartburn, burning in epigastric or substernal area
-may be due to incompetent LES
melena
abnormal black tarry stool
-may be due to ulcers
tenesmus
painful + ineffective straining at stiil
-sense of incomplete evacuation
-may be due to IBS, diarrhea second to infection
