Human Physiology Notes – Week 3
Nerves and Muscles.
During resting potential, the forces of the potassium concentration gradient and the electrostatic
force are not at equilibrium.
Stimulation of Skeletal Muscles.
Electro-stimulator.
-> (stimulus: electrical stimulus).
Nerve.
-> (transduction of stimulus).
Muscle.
->
Muscle Twitch.
Depolarization.
Depolarization opens Na+ channels.
Positively charged portion of the channel is usually attracted to the negative interior of the
cell, depolarization weakens that attraction.
The pore changes shape and opens.
Positive feedback takes over only when a critical level of depolarization is reached: the
threshold.
A – Resting State.
Na+ channels are closed.
Gated K+ channels are closed (but many other K+ channels are open.
B – Rising (Depolarization) Stage.
Nerves and Muscles.
During resting potential, the forces of the potassium concentration gradient and the electrostatic
force are not at equilibrium.
Stimulation of Skeletal Muscles.
Electro-stimulator.
-> (stimulus: electrical stimulus).
Nerve.
-> (transduction of stimulus).
Muscle.
->
Muscle Twitch.
Depolarization.
Depolarization opens Na+ channels.
Positively charged portion of the channel is usually attracted to the negative interior of the
cell, depolarization weakens that attraction.
The pore changes shape and opens.
Positive feedback takes over only when a critical level of depolarization is reached: the
threshold.
A – Resting State.
Na+ channels are closed.
Gated K+ channels are closed (but many other K+ channels are open.
B – Rising (Depolarization) Stage.
