Write Below are a list of descriptions that apply to either

Write:

Below are a list of descriptions that apply to either post synaptic potentials (PSPs), action potentials (APs), both, or neither. Important terms that you should be able to define are bolded.

To answer the question identify PSP / AP / Both / Neither, and then defend your response. In your defense, describe what the bolded terms mean.

For example:

These involve ion channels – both. To change the membrane potential, channels have to open to increase membrane permeability to small charged atom (like Na+, K+, or Cl-).

Descriptions:

These are graded

These are self-propagating

These are unidirectional

These do not involve K

These are in response to ligand gated ion channels

Solution

i)These are graded- post synaptic potentials are graded. Graded potentials are changes in membrane potentials that vary in size.They arise from the summation of individual actions of ligand gated ion chanel proteins and decrease over time and space.

ii)These are self propogating-action potential. Action potential occurs when the change in polarity reaches a threshold.At this point the depolarization becomes self propogating and the nerve impulse travels along the axon of the neuron.

iii) These are unidirectional-action potential.Because absolute refractory period prevents the initiation of an action potential in a region of membrane that has just produced an action potential.

iv) These do not involve K-neither. Both post synaptic potential and action potential involve potasium ions.

v) These are in response to ligand gated ion chanels-post synaptic potentials.Ligand gated ions chanels are opened by neurotransmitters,which results in flow of ions.