Chapter 8 - Neurons Flashcards
in nerve cell trigger zone is blank
the integrator
in nerve cell dendrite = blank
sensor
in nerve cell the axon and synaptic terminal are blank
effector
resting membrane potential is determined by these two things
K+ concentration gradient, membrane permeability to K+ Na+ and Cl-
channel types vary in these two things
threshold (minimum stimulus required to open), speed of opening/closing
differences between action potentials and graded potentials
graded potentials have variable strength, short distances because use diffusion
whereas action potentials are all or none events, and travel long distances
graded potentials occur in blank and blank
dendrites, soma
in graded potentials, signal strength is proportional to blank
stimulus strength
graded potentials move by blank
diffusion
graded potentials decrease in blank as they blank from origin
strength, spread
trigger zone is the blank
high concentration of voltage gated ion channels
sodium and potassium channels have the same blank but differ in their blank
threshold, speed of opening/closing
axon hillock is where
soma meets axon
two gates of voltage gated ion channels
activatino, inactivation
activation gate is blank at rest whereas inactivation gate is blank at rest
closed, open
if activation gate is opened then a blank occurs
action potential
period where there is no way to have another action potential
refractory period
refractory period where only the Na+ activation gate is closed
absolute
refractory period where both Na+ gates are reset
relative
it is possible but difficult to create another action potential during relative refractory period because
potassium ions are still moving out so sodium would have to outdo those ions to create a new action potential
two things that affect the speed of action potential in neuron
diameter of axon, resistance of membrane
larger axon diameter equals blank diffusion
faster
more resistance of leaking of a membrane causes blank diffusion
faster
myelin helps with membrane blank
resistance
two types of conduction in axons
continuous, saltatory
this conduction is when every section of the membrane must be depolarized
continuous
only nodes of Ranvier are depolarized and is faster conduction because the signal is insulated
saltatory conduction