APs Flashcards
APs
how neurons communicate with each other
can result from graded potentials reaching threshold
APs are created at
Trigger zone; bc much higher concentration of voltage gates
depolarization
cell becomes more postive
AP reaches threshold and na rushes into cell
Activation gates open
repolarization
rapid return to negative state
K leaves cell
inactivation gates close and Na stops going into cell
at end activation gates close and inactivation gates open
After potential
period of hyperpolization
k channels open for slightly longer than it takes to get back to resting membrane
return to resting potential
after voltage gated k channels close
NaK pump maintains resting potential
Absolute refractory
complete insensitvty to another stimulus.
From beginning of depol to almost end of repol
relative refractory period
right after absolute
stronger than threshold stim can generate another AP
continuous conduction
used by unmyelinated axons
AP in on site causes AP in next location due to local current of na
cannot go backwards due to absolute refractory period
Salatory conduction
produced my myleinated axons
AP jumps from node of ranvier to node of Ranvier
rapid propagation
Type A nerve fibers
large diameter and myelinated 15-120m/s
motor neurons supplying skeletal muscle and sensory neruons
Type B nerve fibers
medium diameter/lightly myelinated
3 to 15m/s
part of ANS
Type C nerve fibers
small and unmyelinated
conducat at 2 m/s or less
part of ANS
