action potential Flashcards
What connects your brain to the rest of your organs and muscles?
Nerves
Nerves operate like telephone wires, transmitting signals.
What are action potentials?
Electrical impulses sent through nerves
They allow for precise movements by sending signals to muscles.
What is the primary function of neurons?
Transferring information around the body
List the key features of neurons that aid in transferring action potentials.
- Dendrites
- Axon
- Axon terminal
- Myelin sheath
What is a concentration gradient?
The difference in ion concentrations between the inside and outside of a neuron
During resting membrane potential, where are sodium ions more concentrated?
Outside the neuron
During resting membrane potential, where are potassium ions more concentrated?
Inside the neuron
What is the typical range of resting membrane potential in millivolts?
-40 to -90 millivolts
What causes potassium ions to leak out of the neuron?
Potassium leakage channels
What is the role of the sodium-potassium pump?
Pumps potassium back into the cell and sodium out of the cell
What triggers an action potential?
A temporary shift in the neuron’s membrane potential
What are voltage-gated sodium channels?
Channels that open and close based on the voltage difference across the cell membrane
What happens during depolarization?
Sodium ions flow into the neuron, making it less negative
What occurs during repolarization?
Potassium ions exit the neuron, restoring resting potential
What is hyperpolarization?
When the cell becomes more negative than its resting state
What is the all-or-none principle of action potentials?
An action potential is either triggered or it isn’t
What is the absolute refractory period?
Time when it is impossible to send another action potential
What is the relative refractory period?
Time when it is difficult to send another action potential
How does action potential frequency relate to stimulus strength?
Higher frequency indicates a stronger stimulus
What differentiates action potentials from graded potentials?
Action potentials are uniform and sent down the axon, while graded potentials vary in size
Fill in the blank: Many excitatory graded potentials must happen at once to ______.
trigger the action potential
What are graded potentials?
Small changes in membrane potential that can be excitatory or inhibitory
