Unit 5 Flashcards
motility
propulsive movements
* push contents forward
secretion
from exocrine glands into the GI tract
digestion
carbohydrates, protein, fat
* breakdown parts that can be absorbed
what happens when longitudinal muscle contracts
GI tract shortens
what happens when circular muscle contracts
decrease radius of GI tract
what does the symp (NE, Ep) do to the GI tract
relaxtion (inhibit)
what does the parasymp (ACh) do to the GI tract
contraction (stimulate)
what does the enteric system do to the GI tract
relaxtion AND contraction
gastrin source
stomach
* from stomach into the blood
gastrin simulus for release
protein (amino acids) in the stomach
gastrin function
stimulates gastric motility and secretions (HCl)
gastrin summary of function
stimulate stomach to digest food and clear out space in the instestines
secretin source
duodenum
secretin stimulus for release
acid in teh deuodenum
secretin function
inhibit gastric moltility and secretion
stimulate HCO3- secretion from pancrease and liver
secretin summary of function
too much acid coming into the small instestine
cholecystokinin (CKK) source
duodenum
cholecystokinin stimulus for release
fat or protein in the deuodenum
choleycystokinin function
inihbit gastric motility and sectrion
stimulate secretion of digestive enzymes from pancreas
contract gallbladder - release of bile salts into the duodenum
GIP source
duodenum
GIP stimulus for release
glucose inthe duodenum
GIP function
inhibit gastric motility and sectretion
stimulate insulin release
GIP summary of function
slow down rate of glucose in the duodenum and prepare for glucose in the blood
cholecystokinin summary of funciton
sow down rate of stuff enterig the duodenum and release enzymes to break it down
GI smooth muscle contains
gap junction (single unit)
pacemaker cells
peristalsis
propulsive movement in esophagus and intestines
segmentation
mixing movements in intestines
voluntary sphincter type of muscle
skeletal muscle
involuntary sphincter type of mucsle
smooth muscle
zymogen granules
contain amylase
breakdown carbohydrates
duct cells
add bicarbonate (neutralize acidic foods)
salivary amylase
begins breakdown of carbohydrates (inactivated by low pH in stomach)
lingual lipase
begins breakdown of lipids
works at low pH
what does the parasymp do to inhibit the stomach
stimulate enertic NS which inhibits the stomach to relax and expand
oxyntic gland
pit in the epithelium of the stomach with a large number of exocrine cells
parietal cells
release HCl and intrinsic factor
chief cells
have zymogen granules
* release pepsinogen (protein breakdown)
cephalic phase
before food reaches the stomach
* increase in gastric secretion - HCl, pepsinogen
gastric phase
food in the stomach - protein, stretch
* increase in gastric sectrions
intestinal phase
food in the duodenum
* decrease in gastric secretions
bactericidal action
low pH kills most bacteria (except H. poylori)
supply of intrinstic factor (parietal cells)
intrinsic facotr needed for Vit B12 absorption
* Vit B12 needeed for RBC production
what is bile made of
HCO3-
Bilirubin (gives feces brown color)
Bile salts (emulsification of fat)
glucose can either
stay in blood or be stored as glycogen
amino acid function once reaching the liver
- stay in blood
- converted into other amino acids
- convert into glucose
- plasma proteins
compositon of pancreatic juice
- HCO3-
- proteases
- pancreatic amylase
- pancreatic lipase
pancreatic amylase
breakdown carbohydrates
pancreatic lipase
breakdown fat
small instestine absorptive state
segmantation and peristalsis
small intestine postabsorptive state
migrating motor complex
small intestine secretions
HCO3-
bacteria
cholera toxin (increase secretions)
main type of disaccharide
sucrose
main monosaccharide
glucose (only type that can be absorbed)
epithelial disaccharidase
disaccharides –> monosaccharides
how does glucose get into enterocytes
secondary active transport
how does glucose go from enterocytes to the blood
facilitated diffusion
most important lipase
pancreatic lipase
* acting with bile salts present in duodenum
how does the micelle get into the enterocyte
simple diffusion
what part of the micelle does not go into the enterocyte
bile salts
* absorbed in ileum and sent to liver to be reused
where does the chylomicron go after leaving the eneterocyte
lymphatic system
why types of peptides can be absorbed
tripeptides
dipeptides
amino acids
what pancreatic enzyme can do autocatalysis
trypsin
what panreatic enzyme is released by epithelial cells in duodenum and turns trypsinogen into trypsin
enteropeptidase
exopeptidase
remove amino acid from the end
endopeptidase
cleave polypeptide in the middle
what happens if proteins are absorbed
anaphylactic reaction (Antibody production –> vasodilation –> increase BP)
ferritin
storage form of iron
how does iron enter the enterocyte
primary active transport
ferroportin transporter
transports iron into the blood
hepsidin
inhibits ferroportin (decrease of iron absorption)
