4 True/False questions about synapses

[The thinker]

I am revising for my Biophysics module exam (I am actually a physicist), I've been going over old past papers but am having trouble with these questions.

Homework Statement

a) The duration of postsynaptic conductance change is influenced by the concentration of neurotransmitter and affinity of receptors.

b) The time course of postsynaptic potential is different to that of the underlying conductance change.

c) The duration of the EPSP is determined by the time course of transmitter release.

d) The time course of EPSP is determined by diffusion of the neurotransmitter from the cleft

The Attempt at a Solution

a) True, the higher the affinity and the greater the concentration of neurotransmitter the longer the ion channels will be open and hence the longer the postsynaptic conductance change will last.

b) False

c) False, the duration of the EPSP is also influenced by the membrane time constant, the synaptic conductance change and the speed of neurotransmitter evacuation from the cleft.

d) False, the time course of the EPSP is also influenced by the membrane time constant, the synaptic conductance change and the speed of neurotransmitter evacuation from the cleft.

Basically I am confused about how all these factors exactly influence each other but the online lecture notes are terrible and I can't afford a book! Could anyone help clarify?

Thanks.

 

[Nino MMP]

The duration of the postsynaptic conductance change is determined by how long the ion channels remain open. The concentration of neurotransmitter and the affinity of the receptors influence how long the channels remain open. The time course of the postsynaptic potential is different to that of the underlying conductance change because the potential is a combination of the conductance change, the membrane time constant, the synaptic conductance change, and the speed of neurotransmitter evacuation from the cleft. The duration of the EPSP is determined by these factors as well.