RESTING MEMBRANE POTENTIAL

True or False: excitable tissues are built up energy

True

Muscle tissue -

contract

Nerve tissue -

send electrical impulses

Resting membrane potential:

a charge difference that sits from the inside of a cell, compared to the outside of a cell & its waiting to be excited so that it could do its activity for muscles (contract) & for neurons (to send a signal).

Phospholipid bilayer:

a fatty layer that separated the internal from external, doesn’t let anything in thats large or charged

K+ leak:

K+ flows out of the neuron

Na+ leak:

Na+ flows in the neuron

Voltage-gated Na+:

Na+ rushes in when opened (depolarization)

Voltage gated K+:

K+ flows out when opened (repolarization)

Na+/K+ pump:

moves Na+ out & K+ in (against gradient, opposite, bringing it back)

Threshold

the membrane potential that must be reached to trigger an action potential, typically around -55mv

What is a volt?

→ a unit of electrical potential differences

→ measures energy between two points

→ in context of a neuron, potential energy is available to move ions across the membrane

Voltage-gated Na+ channel:

open rapidly during depolarization

Voltage-gated K+ channel:

opens slowly during repolarization, returns membrane to RP

If threshold is reached, voltage gates Na+ channels open, leading to rapid ________.

depolarization