Anatomy lab - Action Potential Flashcards
What allows for the action potential to occur?
Voltage-gated sodium channels
What are the two voltaged-gated channels?
Na+ and K+
At resting potential, voltage-gated Na+ channels are what?
Closed
Conformational changes open voltage-gated channels when the membrane is what?
Depolarized
What happens during resting potential?
Both voltage gated Na+ and K+ channels are
closed
What is initial depolarization?
Some Na+ channels open and if so then the threshold is surpassed and an action
potential is initiated.
What happens during the rising phase of action potential?
Na+ channels open quickly. K+ channels are still closed.
What happens during the falling phase of action potential?
Na+ channels self-inactivate, K+ channels are open.
Why does the membrane potential increase during stage 3 of the action potential?
The voltage gated Na+ channels are open, but the voltage gated K+ channels have not opened yet.
Why does the membrane potential decrease during stage 4 of the action potential?
The voltage gated K+ channels open, the voltage gated Na+ channels close.
What does action potential jump from on the axon?
Node to node
What wraps around the axon?
Schwann cells
What does Schwann cells form?
myelin sheath
What is the term for the axon terminal?
Pre-synapse
What is the term for the middle terminal?
Synapse
What is the term for dendrite?
Post-synapse
What synapse would likely INCREASE firing the action potential?
Excitatory synapses
What synapse would likely DECREASE firing the action potential?
Inhibitory synapses
Excitatory postsynaptic
potential (EPSP)
Depolarization, Na+ inflow