Table of Contents
What is required for an action potential to occur?
Sufficient current is required to initiate a voltage response in a cell membrane; if the current is insufficient to depolarize the membrane to the threshold level, an action potential will not fire. Examples of cells that signal via action potentials are neurons and muscle cells.
What type of event is required for an action potential to be generated?
What event triggers the generation of an action potential? — The membrane potential must return to its resting value of -70 mV from the hyperpolarized value of -80 mV. — The membrane potential must depolarize from the resting voltage of -70 mV to a threshold value of -55 mV.
What ions are involved in action potential?
An action potential begins at the axon hillock as a result of depolarisation. During depolarisation voltage-gated sodium ion channels open due to an electrical stimulus. As the sodium ions rush back into the cell, their positive charge changes potential inside the cell from negative to more positive.
Which type of event is required for an action potential to be generated quizlet?
Action potentials are generated when voltage-gated Na+ and voltage-gated K+ channels are activated in the axon. Voltage-gated channels are only located in the axon of a neuron.
How an action potential is generated and propagated?
The action potential propagates with essentially the same waveform all along the axon. The velocity of action potential propagation varies with myelination and axon size. In unmyelinated axons, the velocity varies approximately with the square root of axon diameter.
What structures in the cell membrane are needed for the action potential?
The principal ions involved in an action potential are sodium and potassium cations; sodium ions enter the cell, and potassium ions leave, restoring equilibrium. Relatively few ions need to cross the membrane for the membrane voltage to change drastically.
Where is action potential generated?
Action potentials are propagated along the axons of neurones via local currents. Local currents induce depolarisation of the adjacent axonal membrane and where this reaches a threshold, further action potentials are generated.
What is the order of events in an action potential quizlet?
Terms in this set (14)
- depolarization of cell membrane.
- generation of action potential.
- action potential moves down axon.
- repolarization occurs.
- action potential arrives at axon terminal.
- calcium channels open and calcium ions move into the neuron.
- neuron makes and stores neurotransmitters in the vesicles.
What is the first event of an action potential quizlet?
The first step with regards to the generation of an action potential is the opening of voltage-gated potassium channels at the axon hillock.
How is an action potential started and propagated quizlet?
How is an action potential propagated along an axon? An influx of sodium ions from the current action potential depolarizes the adjacent area. [the influx of sodium ions depolarizes adjacent areas, causing the membrane to reach threshold and cause an action potential.
Which of the following structures can generate an action potential?
Axon – The long, thin structure in which action potentials are generated; the transmitting part of the neuron. After initiation, action potentials travel down axons to cause release of neurotransmitter.
What are the 5 steps of an action potential in order?
What Are The 5 Steps Of An Action Potential?
- Resting potential.
- Threshold.
- Rising phase.
- Falling phase.
- Recovery phase.
What are the 7 steps of action potential?
7 Cards in this Set
| STEP 1 | Threshold stimulus to -55mv | Stimulus |
|---|---|---|
| STEP 4 | At +30mv, Na channels close and K ions channels open | K ions |
| STEP 5 | K floods out of the cell | Out of cell |
| STEP 6 | Hyperpolarization to -90mv | Hyper |
| STEP 7 | K channels close and tge resting potential is re-established at -70 | Re-established |
What are the steps of an action potential quizlet?
Terms in this set (4)
- Step 1 – Resting Potential. Sodium and potassium channels are closed.
- Step 2 – Depolarization. Sodium channels open in response to a stimulus.
- Step 3 – Repolarization. Na+ channels close and K+ channels open.
- Step 4 – Resting Conditions. Na+ and K+ channels are closed.
What causes an action potential to be initiated quizlet?
Action potentials are initiated by membrane depolarization which causes the opening of voltage-gated ion channels, which causes an influx of sodium into the cell.
What event triggers an action potential quizlet?
What event triggers the generation of an action potential? The membrane potential must depolarize from the resting voltage of -70 mV to a threshold value of -55 mV. This is the minimum value required to open enough voltage-gated Na+ channels so that depolarization is irreversible.