Action potential steps flashcards
Learn the steps of action potential in neurons, a fundamental concept in physiology.
Quiz(14 questions)
1. What occurs first in the action potential sequence?
Terms in this Study Set(19)
What is an action potential?
A rapid change in membrane potential that propagates along a neuron.
Resting membrane potential
The voltage across a cell's membrane when it is not actively transmitting signals, typically around -70 mV.
Threshold potential
The membrane potential that must be reached to trigger an action potential, usually around -55 mV.
Depolarization phase
The phase where sodium channels open, allowing Na+ ions to flow into the neuron, making it more positive.
Repolarization phase
This phase occurs after depolarization when potassium channels open, allowing K+ to exit the cell and restore negativity.
What happens during hyperpolarization?
The membrane potential temporarily becomes more negative than the resting potential due to excess K+ outflow.
True or false: Action potentials are all-or-nothing events.
True, because they either fully occur or do not occur at all.
Difference between depolarization and repolarization
Depolarization involves Na+ influx, while repolarization involves K+ efflux.
Fill in the blank: The action potential peaks around ____ mV.
Approximately +30 mV.
What restores ion concentrations after an action potential?
The sodium-potassium pump (Na+/K+ ATPase) helps restore resting membrane potential.
What is the refractory period?
A phase following an action potential during which a neuron cannot fire another action potential.
True or false: Myelination increases the speed of action potentials.
True, because myelin sheaths insulate the axon and facilitate faster conduction.
Question: What role do voltage-gated channels play?
They open in response to changes in membrane potential, enabling ion flow.
What triggers the opening of sodium channels?
The membrane depolarization reaching the threshold potential.
Fill in the blank: After an action potential, the membrane potential returns to ____ mV.
About -70 mV.
Comparison: Absolute vs. relative refractory period
Absolute: no action potential can occur; Relative: a greater-than-normal stimulus can trigger one.
What ion mainly causes depolarization?
Sodium (Na+) ions enter the neuron.
What ion mainly causes repolarization?
Potassium (K+) ions exit the neuron.
True or false: Action potentials travel in both directions along an axon.
False, because they typically propagate away from the initial segment.
Questions in this Study Set(14)
1. What occurs first in the action potential sequence?
2. Which statement about the threshold potential is correct?
3. Which ion is primarily responsible for repolarization?
4. What is the result of the sodium-potassium pump after an action potential?
5. In which phase does the membrane potential become positive?
6. Which phase follows depolarization?
7. What defines the absolute refractory period?
8. Which of the following does NOT contribute to action potential propagation?
9. What is the main effect of myelination on action potentials?
10. Fill in the blank: During hyperpolarization, the membrane potential is ____ than resting potential.
11. What initiates an action potential?
12. What happens during the relative refractory period?
13. Which sequence represents the order of events in action potentials?
14. Difference between action potential and graded potential?
Related Study Sets
Aktionspotential Schritte Karteikarten
Klausur: Herzzyklus
Atemvolumina Karteikarten
Cardiac cycle flashcards
Sliding filament theory flashcards
Blood pressure systolic diastolic
Digestive enzymes by organ
Niere Filtration Karteikarten
Create Your Own Study Set
Upload a PDF, paste your notes, or describe a topic – AI generates flashcards, quizzes and more in seconds.
