Question

classify each of the following statements as being descriptive of graded potentials or action potentials.

Explanation:

Graded potentials are local changes in membrane potential that vary in amplitude depending on the strength of the stimulus. They can be depolarizations or hyperpolarizations, are mediated by ligand - gated channels or other chemical/physical changes, can be summed, and their amplitude decreases with distance. Action potentials are all - or - none events, have a refractory period, are conducted without decrement, depend on voltage - gated channels, and are usually initiated by a graded potential reaching a threshold (about 15 mV depolarized relative to the resting potential).

Answer:

Graded Potential:

• Mechanism depends on ligand - gated channels or other chemical or physical changes
• Can be a depolarization or a hyperpolarization
• Amplitude varies with size of the initiating event
• Can be summed
• Is conducted decrementally, that is, amplitude decreases with distance

Action Potential:

• All - or - none
• Has a refractory period
• Threshold is usually about 15 mV depolarized relative to the resting potential
• Is conducted without decrement
• Mechanism depends on voltage - gated channels
• Initiated by a graded potential
• Is only a depolarization
• Has no refractory period (this is incorrect for action potential, action potentials have a refractory period)
• Has no threshold (this is incorrect for action potential, action potentials have a threshold)