Download Neuron Physiology Notes

Neuron Physiology Notes-The Nerve Impulse
_________________-nerve impulses which are sent by a
change in electrical charge in the cell membrane.
 ______ (Na+) highly concentrated outside of cells
 ___________ (K+) highly concentrated inside cells
_________________________- Ions move from high concentration to a low
concentration passively
 ______________ pumps moves ions actively using ATP
Active Pump
Creating a Resting Potential
 _________________________
– open and close
– let ions through
 ________________________
– Ions move against a gradient
– Use ATP to work
 _________________________
– Ions move with the gradient
– Ions move from _________
to low concentration
Passive Pump
Stages of a Nerve Impulse
STAGE
1) Neuron at “resting
membrane potential” is
polarized with a resting
potential of (-70 mv)
2.) Neuron is stimulated
by the influx of a
neurotransmitters that
causes sodium channels
to open. Sodium moves
inward causing neuron
to depolarize. (-62mv)
3.) Threshold is reached
when enough sodium
enters the neuron to
change the potential to
(-55mv) which causes
“trigger zone” to allow
even more sodium into
the neuron. Action
Potential occurs,
message transmitted.
4.) Neuron continues to
depolarize as sodium
channels further open.
5.) Potassium channels
open and potassium
diffuses out so
membrane can be repolarized. Occasionally
the membrane is
hyperpolarized and then
returns to polarized
state.
DRAWING of Neuron
Graph
 Saltatory nerve impulse conduction
 Myelinated vs. unmyelinated axons
 Speed of nerve impulse
 All or None Response
 Refractory period