Page 16 Flashcards
(30 cards)
Glucose transport through placenta via
Facilitated diffusion
Definition of active transport
Movement against concentration gradient using energy and carrier proteins
Primary active transport
Uses ATP directly for energy
Na+-K+ ATPase pump
Moves 3 Na+ out, 2 K+ in; inhibited by digitalis
Ca2+-ATPase pump
Moves calcium into organelles using ATP
H+-K+ ATPase pump
Proton pump in stomach and kidneys; inhibited by omeprazole
Secondary active transport
Uses gradient (e.g., Na+) to move other substances uphill
Na+-glucose co-transport
Na+ moves downhill to drive glucose uphill (symport)
Na+-Ca2+ counter-transport
Na+ moves downhill to drive Ca2+ uphill (antiport)
Definition of passive transport
Transport without metabolic energy; includes diffusion and osmosis
Simple diffusion
Not carrier mediated, moves down electrochemical gradient
Facilitated diffusion
Carrier-mediated, moves down electrochemical gradient, limited by Vmax
Osmosis
Water moves from low solute concentration to high solute concentration via semipermeable membrane
Active transport across cell membranes
Requires energy production by the cell
Active transport of ions is mainly due to
Pumps
Choroid plexus transport mechanism
Active transport of sodium ions
Drug inhibiting H+/K+ ATPase
Omeprazole
Na+ absorption in renal epithelium
Na+-K+ pump (basolateral membrane)
Glucose absorption in kidney
Secondary active transport
Glucose and amino acid reabsorption in PCT
Secondary active transport
Amino acid and glucose absorption in small intestine
Active transport
Rate of simple diffusion is inversely proportional to
Thickness of the membrane
Transport affected by membrane thickness
Diffusion
Rate of diffusion depends on
Total surface area of the membrane
