Question

An inhibitory neurotransmitter may cause the movement of which ion across the membrane?

a) Na+

b) Mg2+

c) K+

d) Ca2+

Excitatory neurotransmitters produce which types of electrical responses in the postsynaptic neuron?

a)Hyperpolarizations

b)EPSPs

c)IPSPs

d)Threshold level inhibitions

Neurotransmitters induce membrane potential changes:

a) by opening voltage-gated Na+ channels on the postsynaptic axon hillock.

b) on the presynaptic cell body.

c) by opening mechanically-gated Mg2+ channels on the postsynaptic axon.

d) on the postsynaptic dendrites and cell body

Answer 1

1. An inhibitory neurotransmitter creates the IPSP(Inhibitory postsynaptic potential) by opening the K+ and Cl- channels which hyperpolarize the membrane and drive neuron away from action potential. Thus C is correct.

2.excitatory neurotransmitters create a local increase of permeability of sodium ion channels (ligand gated sodium channels open) which causes local depolarization of membrane and generating Excitatory Postsynaptic Potential (EPSP). Thus B is correct.

3.Neurotransmitters induce membrane potential change by opening the Channels on the axon hillock of post synaptic neuron, which are voltage-gated sodium channels, they open when the voltage on the axon hillock reaches threshold i.e. - 55mV and initiate the depolarising membrane. Thus a is correct