3.2 Actions of Neurons Flashcards
What is resting potential?
The difference in electric charge between the inside and outside of a neuron’s cell membrane.
What happens during resting potential?
Neuron is at rest.
What is action potential?
An electric signal that is conducted along the length of a neuron’s axon to a synapse.
What happens during action potential?
The sodium channels in that area of the cell membrane open, allowing Na+ ions to flood in. They spread and increase electric charge.
Does the myelin sheath speed up or slow down the action potential?
Speed up.
What is the refractory period?
The time following an action potential during which a new action potential cannot be initiated.
How does an action potential go back to resting potential?
Na+ channels inactivate themselves for several milliseconds. The K+ channels open, allowing excess K+ ions to escape. The exit of positively charged K+ ions returns the electrical charge to its original negative state. Then, to restore chemical balance, a series of special channels called ion pumps work to redistribute the ions. They push Na+ ions out and pull K+ ions in until everything is rebalanced and resting potential is restored.
What are terminal buttons?
Knoblike structures at the end of an ion.
What are neurotransmitters?
Chemicals that transmit information across the synapse to a receiving neuron’s dendrites.
What are receptors?
Parts of the cell membrane that receive neurotransmitters and either initiate or prevent a new electric signal.
What is a sending neuron called?
Presynaptic neuron
What is a receiving neuron called?
Postsynaptic neuron
What is the sending and receiving of chemical neurotransmitters called?
Synaptic transmission
What is it called when neurotransmitters are absorbed by the terminal button of the presynaptic neuron (or neighboring glial cells)?
Reuptake
What is it called when neurotransmitters drift out of the synapse, away from the receptors.
Diffusion
