Movement of ions through channels and concentration gradients

K+ leak channels

K+ flows in and out of cell based on concentration gradient and electrical attraction

Membrane Potential

difference in charge between the outside and inside of the cell

negative

The inside of the cell is typically more ________ the outside of the cell at rest

Na+/K+ Pump

uses energy (ATP hydrolysis) to drive Na+ out of the cell and K+ into the cell

Non-gated Channels

always open

not influenced by external factors

primarily important in maintaining the resting membrane potential

Voltage-gated (Gated Channels)

open in response to changes in electric potential across the plasma membrane

Ligand-gated (Gated Channels)

open in response to binding of neurotransmitters or other signaling molecules

selectivity barriers

Transporters have ___________ based on diameter size and chemical composition of channel proteins

the size of potassium

The determining factor of a potassium channel is

the size of sodium and the water molecule

The determining factor of a sodium channel is

separate proteins

Potassium channels are 4 ______

parts of the same protein

Sodium channels are 4 _________

axon

Voltage gated channels are located along the ______ of the neuron

dendrite

Ligand gated channels are located on the ________ of the neuron

Sodium/Potassium Pump and Leak Channel

Two proteins responsible for maintain membrane potential

Depolarization

when sodium enters the cell

Repolarization

K+ flows out of the cell

Hyperpolarization

When the membrane is more negative than the resting potential

inactivation ball

The sodium channel is inactivated by the _______

down its concentration gradient

Since there is more potassium inside of the cell than outside, it flows _________ out

electrical attraction

Due to the negative charge in the cell, potassium flows in by ___________

increase; decrease

Ligand-gated ion channels cause the initial _____ or ______ in membrane potential