chapter 4.2

Question 1

neurotransmitters

Answer 1

chemicals released from a neuron’s terminal buttons when it fires. Diffuse across the synaptic clefts and interact with specialized receptor molecules on the receptive membranes of the next neurons in the circuit.

Question 2

When neurotransmitter molecules bind to postsynaptic receptors, they may:

Answer 2

Depolarize – decrease the resting membrane potential.

Hyperpolarize – increase the resting membrane potential.

Question 3

Excitatory postsynaptic potentials (EPSPs)

Answer 3

postsynaptic depolarizations; increase the likelihood that the neuron will fire.

Question 4

Inhibitory postsynaptic potentials (IPSPs)

Answer 4

postsynaptic hyperpolarizations; decrease the likelihood that the neuron will fire.

Question 5

graded responses

Answer 5

the amplitudes of EPSPs and IPSPs are proportional to the intensity of the signals that elicit them. Weak signals elicit small postsynaptic potentials and strong signals elicit large ones.

Question 6

The transmission of postsynaptic potentials has two important characteristics:

Answer 6

it is rapid (instantaneous) and the transmission of EPSPs and IPSPs is decremental, EPSPs and IPSPs decrease in amplitude as they travel through the neuron. They do not travel far.