Membrane & Action Potentials Flashcards
sodium potassium pumps ____ Na+ ions _____
3 Na+ ions out
sodium potassium pumps ___ K+ ions ____
2 K+ ions in
what ion(s) usually have an inward gradient (greater concentration outside the cell)
Na+, Cl-, Ca2+
what ion(s) usually have a slight outward gradient (greater concentration inside the cell)
K+
what does the Nerst equation calculate?
equilibrium potential for each ion based on its concentration gradient
what does the Goldman constant field equation give?
gives predicted membrane potential based on concentration gradients for principal permanent ions
changes in the concentration of what ion cause the most changes in Em and why?
K+ concentration because it is most permeable
______ is when the inside of cell becomes less negative
depolarization
in the AP, what ion causes depolarization?
Na+ influx causes depolarization
in the AP, what ion causes hyper polarization?
K+ efflux causes hyper polarization
distance of travel for an AP depends on what factors?
axon diameter and axonal membrane resistance
what is present to enhance the speed of propagation of an AP
the axon is covered in myelin and separated by nodes of ranvier
what does saltatory conduction mean
action potentials will “jump” from one node to the next
