ion channels pt.2

leak channel (passive) stimulus to open/close

alway opens

leak channel comment

help establish RMP

chemically gated Na + channel stimulus open/close

excitatory chemicals

chemically gated Na+ channel comment

depolarize to threshold

chemically gated K+ channel stimulus to open/close

inhibitory chemicals

chemically gated K+ channel comment

hyperpolarize

voltage gated Na+ channel stimulus to open/close

open @ = -60mV, close @= +30mV

voltage gated Na+ channel comment

rapid depolarization of action potential

voltage gated K+ channel simulus to open/close

open @= +30mV, close @= -70mV

voltage gated K+ channel comment

@ synaptic knob

mechanically gated channel stimulus to open/close

physical pressure

mechanically gated channel comment

found in sensory neurons

threshold

voltage necessary to begin opening voltage gated channels

graded potential

small localized change in the RMP

subthreshold potential

membrane potential change in a neuron that is not strong enough to trigger an action potential

depolarization

if the NT opens a sodium channel, sodium ions will ENTER the cell, the neuron will become POSITIVE inside.

in depolarization when a neuron depolarizes or becomes excited it will have

EPSP

hyperpolarization

If the NT opens a potassium channel, potassium ions will EXIT the cell. The neuron will become NEGATIVE

In hyperpolarization when a neuron hyperpolarize it will

IPSP

Summation

several stimulations added together

temporal summation

results from continuous stimulation of a single synapse to add either EPSP or IPSP together.

spatial summation

results from simultaneous stimulation of numerous synapses to add either EPSP or IPSP’s together