Flashcards in Drug Absorption #2 Deck (94)
T/F Passive diffusion is uni-directional
FALSE: can move in either direction (the concentration gradient determines which direction the molecule moves)
What are the 2 routes in which blood can diffuse?
molecules move directly through the membrane
-this is the most common
molecules move between cells
-has a limiting factor (size of the molecules)
What is the limiting factor of paracellular transport?
the size of the molecule
T/F Carriers are typically proteins
What are the 2 types of carrier mediated transport?
Carrier Mediated Transport (2)
-are specific (only move one type of molecule)
-typically located in specific areas of the GI tract
T/F Carriers CAN NOT be saturated
FALSE; there are only a certain number of carriers, which means they can be saturated
T/F Carriers can be inhibited
T/F Carrier transport is one direction
TRUE (mucosal side --> to the blood)
Which transport system requires ATP energy?why?
Active transport b/c it can occur from a region of lower concentration to higher concentration
chemical altering of the drug molecule by the body
What is the effect of metabolites on bioavailability?
although metabolites are inactive--> they decrease bioavailbility because there would be a reduced amount of drug that would get to the site of action
efflux transporters (2)
-going in the opposite direction than what we would like
-typically P glycoproteins
P glycoproteins (3)
-pump the drug back in the direction in which it came from
-not as specific as carrier proteins
_____ are thought to cause tolerance to cancer therapeutic agents
What would be the effect of P glycoproteins on the bioavailability of the drug?
it would DECREASE the bioavailability because its taking the drug molecules in the opposite direction than we want them to go--> not allowing them to ultimately get to the site of action
What part of the stomach is where most secretion occurs?
the middle of the stomach
holds material in the stomach to control how it moves to the pylorus
T/F The stomach is very muscular
What are the functions of the stomach? (4)
-site of the beginning of digestion
-regulate the delivery of nutrients
The secretion of ____ typically destroys the bacteria that make it to the stomach
What are the secretion cells in the stomach? (4)
mucus provides ____ and ____ protection
chemical and physical
secrete pepsinogen (gets converted to pepsin)
____ begins the digestion process in the stomach
secrete primarily HCl and intrinsic factors