CH 2.1 Summary

Question 1

The synapse is the point of communication between two neurons.

Answer 1

Charles S. Sherrington’s observations of reflexes enabled him to infer the existence of synapses and many of their properties.

Question 2

Because transmission through a reflex arc is slower than transmission through an equivalent length of axon

Answer 2

Sherrington concluded that some process at the synapses delays transmission.

Question 3

Graded potentials (EPSPs and IPSPs) summate their effects. The summation of graded potentials from stimuli at different times is temporal summation.

Answer 3

The summation of potentials from different locations is spatial summation.

Question 4

Inhibition is more than just the absence of excitation.

Answer 4

It is an active brake that suppresses excitation.

Question 5

For effective functioning of the nervous system

Answer 5

Inhibition is just as important as excitation.

Question 6

Stimulation at a synapse produces a brief graded potential in the postsynaptic cell.

Answer 6

An excitatory graded potential (depolarization) is an EPSP. An inhibitory graded potential (hyperpolarization) is an IPSP.

Question 7

An EPSP occurs when gates open to allow sodium to enter the neuron’s membrane.

Answer 7

An IPSP occurs when gates open to allow potassium to leave or chloride to enter.

Question 8

The EPSPs on a neuron compete with the IPSPs

Answer 8

The balance between the two increases or decreases the neuron’s frequency of action potentials.