Biology

Eric P. Widmaier; Linda E. Graham; Robert J. Brooker

Chapter 41

Neuroscience I: Cells of the Nervous System - all with Video Answers

Educators

Chapter Questions

Problem 1

In vertebrates, the brain and the spinal cord constitute
a. the peripheral nervous system.
b. the efferent division of the nervous system.
c. the central nervous system.
d. the autonomic nervous system.
e. the central and peripheral nervous systems.

Ummatul Choudary

Ummatul Choudary

Numerade Educator

Problem 2

The structures of a neuron that function mainly in receiving signals from other neurons are the
a. myelin sheaths.
b. axons.
c. axon terminals.
d. dendrites.
e. $\mathrm{K}^{+}$ channels.

Ummatul Choudary

Ummatul Choudary

Numerade Educator

Problem 3

The myelin sheath
a. is produced by neurons in the peripheral nervous system.
b. is formed only around neurons in the brain.
c. is present on all neurons.
d. is generally present around long axons in either the CNS or the PNS.
e. significantly slows transmission along neurons.

Ummatul Choudary

Ummatul Choudary

Numerade Educator

Problem 4

Neurons that function mainly in connecting other neurons in the central nervous system are
a. sensory neurons.
b. efferent neurons.
c. motor neurons.
d. afferent neurons.
e. interneurons.

Ummatul Choudary

Ummatul Choudary

Numerade Educator

Problem 5

The difference in charges across the plasma membrane of an unstimulated neuron is called
a. an EPSP.
b. the resting membrane potential.
c. an IPSP.
d. the graded potential.
e. the action potential.

Ummatul Choudary

Ummatul Choudary

Numerade Educator

Problem 6

Which of the following contribute(s) to the resting membrane potential?
a. the relative leakiness of the membrane to $\mathrm{Na}^{+}$ and $\mathrm{K}^{+}$
b. active transport of ions across the membrane
c. concentration of $\mathrm{Na}^{+}$ and $\mathrm{K}^{+}$ inside and outside of the cell
d. all of the above
e. b and c only

Ummatul Choudary

Ummatul Choudary

Numerade Educator

Problem 7

A neuron has reached a threshold potential when it has depolarized to the point where
a. the voltage-gated $\mathrm{Na}^{+}$ channels have become inactivated.
b. sufficient numbers of voltage-gated Na $^{+}$ channels open to initiate a positive feedback cycle, contributing to further depolarization.
c. voltage-gated $\mathrm{K}^{+}$ channels close.
d. voltage-gated $\mathrm{Na}^{+}$ channels close.
e. both $b$ and $c$ occur.

Ummatul Choudary

Ummatul Choudary

Numerade Educator

Problem 8

The speed of transmission of an action potential along an axon is influenced by
a. the presence of myelin.
b. an increased concentration of $\mathrm{Ca}^{2+}$
c. the diameter of the axon.
d. all of the above.
e. a and c only.

Ummatul Choudary

Ummatul Choudary

Numerade Educator

Problem 9

Gap junctions are characteristic of
a. electrical synapses.
b. chemical synapses.
c. acetylcholine synapses.
d. GABA synapses.
e. synapses between motor neurons and muscle cells.

Ummatul Choudary

Ummatul Choudary

Numerade Educator

Problem 10

The response of the postsynaptic cell is determined by
a. the type of neurotransmitter released at the synapse.
b. the type of receptors the postsynaptic cell has.
c. the number of $\mathrm{Na}^{+}$ channels in the postsynaptic membrane.
d. the number of $\mathrm{K}^{+}$ channels in the postsynaptic membrane.
e. all of the above.

Eric Pacheco

Numerade Educator