Digestion and Absorption Flashcards
___ emulsifies fats, and ___ digests them
bile, pancreatic enzymes
About __ L of fluid passes thru the GI system each day
__L is ingested
The rest represent secretions from system
9L passes
2L ingested
__mL of fluid is eliminated/lost in stool
100mL
Enterocytes (which cover villi) have apical cell membrane bound _____ (enzyme)
peptidases and disaccharides
crypts of Lieberkuhn
invaginations of epithelium between villi
lined with younger epithelial cells
enterocyte contains
aa
glucose
monoglycerides
membrane enzymes
enteric endocrine cell
gastrin
cholecystokinin
secretin
major mech to inc surface area
intestinal folds
villus structures
microvilli
on apical surface of enterocytes
where chyme undergoes largest amount of digestion with significant nutrient absorption
jejunum
mainly involved w/ absorption of water/salts from material that has not been digested
colon
iron absorption
duodenum
B12 absorption
terminal ileum
IF is secreted by
parietal cells of stomach
IF binds B12 in the ___, and escorts it to the ___.
duodenum
to the
terminal ileum
then absorbed into portal blood
sugars/amino acids are absorbed via
carrier-mediated facilitated diffusion
lactose
sucrose
maltose
disaccharides
glucose
fructose
galactose
monosaccharides
glucose and lactose are transported by which transporter
Na+dependent transport
fructose is transported by which transporter
non-Na+ dependent transporter
most transporters for aa into enterocyte are
Na-dependent co transporters
di-peptides and tri-peptides are transported into enterocyte by
H+ ion dependent co-transporters
micelles enable FA and CHL to come in contact with and easily diffuse across the _____.
triglycerides are then reassembled and enter the ____ where they are repackaged into _____
brush border (epithelial cells)
smooth endoplasmic reticulum
chylomicrons
chylomicrons contain many of components found in micelle EXCEPT
bile acids
chylomicrons are secreted from cell by ______ into the ______
exocytosis; lymphatics
about ____mL of fluid leave the SI and enter colon each day
1500mL
__mL of the fluid entering the SI, is lost in stool
100mL
Which transports more water, colon epithelial cell, or small intestinal cell?
colon epithelial cell
5 cell types of SI
enterocyte goblet cell enteric endocrine cell stem/progenitor cell paneth cell (lysozyme)
FAs and glycerol are absorbed through
diffusion
of all enzymes, only ____ and ____ need to be activated
stomach and pancreatic proteases
