Action Potential

What is the insulating membrane that surrounds parts of the axon that helps to protect & propagate action potential?

• Axon

• Dendrites

• Node of Ranvier

• Myelin Sheath

What number(s) on the graph represents the THRESHOLD level of stimulus?

• 1 and 5

• 2

• 3

• 6

At which point on the diagram does depolarisation of the axon occur? 

• A

• B

• C

• D

Describes the fact that a neuron fires at the same intensity despite the intensity of the stimulus.

• Threshold

• Repolarization

• All or None Principle

• Action Potential

Identify each phase of the action potential: Repolarization

which ion is responsible for the repolarization of the cell interior after depolarization during an action potential?

• calcium (Ca2+)

• chloride (Cl-)

• manganese (Mn)

• potassium (K+)

• sodium (Na+)

Opening of sodium channels in the membrane of a neuron results in

• Depolarization

• Repolarization

• Hyperpolarization

• Increased negative charge inside the membrane

• Reestablishment of the resting potential

When a membrane potential reaches +40mV, ________ channels open, ________ occurs, and ________ channels close.

• Sodium, depolarization, potassium

• Potassium, depoloarization, sodium

• sodium, repolarization, potassium

• postassium, repolarization, sodium

During the threshold and rising action potential (depolarization), what channels are opening?

• Sodium

• Potassium

• Calcium

• Both sodium and Potassium

What is the threshold potential, and why is it important in the generation of an action potential?

• The threshold potential is the minimum voltage required to open potassium channels, and it is important for repolarization.

• The threshold potential is the minimum voltage required to open sodium channels, and it is important for initiating an action potential.

• The threshold potential is the maximum voltage the membrane can reach, and it is important for preventing over-excitation.

• The threshold potential is the resting membrane potential, and it is important for maintaining cellular homeostasis.

Tags

DOK Level 2: Skill/Concept