Question 1

Which of the following best describes the main difference between a nerve net and a central nervous system (CNS)?

Accepted Answer

A nerve net consists of diffuse arrangements of cells, while a CNS contains large clusters of neurons called ganglia.

Question 2

Which part of a neuron is primarily responsible for integrating incoming signals and generating outgoing signals to the axon?

Accepted Answer

Cell body (soma)

Question 3

The resting membrane potential of a typical neuron is approximately $$-70\ \mathrm{mV}. $$Which of the following best explains why the inside of the neuron is negative relative to the outside?

Accepted Answer

The sodium-potassium pump exports three sodium ions for every two potassium ions it imports, creating a net negative charge inside.

Question 4

Tetrodotoxin, a neurotoxin found in puffer fish, blocks voltage-gated sodium channels. What is the most immediate effect of this toxin on neuron function?

Accepted Answer

It prevents the generation of action potentials.

Question 5

During the rising phase of an action potential, which of the following occurs?

Accepted Answer

Voltage-gated sodium channels open, allowing Na$$^+ to $$flow in.

Question 6

Why do action potentials only travel in one direction along an axon?

Accepted Answer

Voltage-gated sodium channels become temporarily inactivated after opening, creating a refractory period.

Question 7

Which of the following adaptations allows vertebrate neurons with small axon diameters to transmit action potentials rapidly?

Accepted Answer

Myelination by glial cells such as Schwann cells or oligodendrocytes

Question 8

A patient with multiple sclerosis (MS) experiences muscle weakness and reduced coordination. Which of the following best explains these symptoms?

Accepted Answer

Progressive loss of myelin sheaths, slowing electrical signal transmission

Question 9

Which of the following events occurs first when an action potential reaches the axon terminal of a presynaptic neuron?

Accepted Answer

Voltage-gated Ca$$^{2+}$$ channels open, allowing calcium ions to enter the presynaptic cell

Question 10

Which of the following best describes the effect of an inhibitory postsynaptic potential (IPSP) on a neuron?

Accepted Answer

It causes membrane hyperpolarization, decreasing the likelihood of an action potential.

Question 11

If several excitatory postsynaptic potentials (EPSPs) occur close together in time at the same synapse, what is the likely result?

Accepted Answer

The EPSPs will sum, increasing the likelihood of reaching threshold for an action potential.

Question 12

Which of the following is a function of glial cells in the nervous system?

Accepted Answer

Nourishing and insulating neurons

Question 13

Which division of the peripheral nervous system (PNS) is responsible for transmitting sensory information to the central nervous system (CNS)?

Accepted Answer

Afferent division

Question 14

Which part of the brain is primarily responsible for coordinating complex motor patterns such as balance and coordination?

Accepted Answer

Cerebellum

Question 15

Which of the following best describes the role of the corpus callosum?

Accepted Answer

It connects the two hemispheres of the cerebrum.

Question 16

A person is startled by a loud noise, and their heart rate increases rapidly. Which division of the autonomic nervous system is primarily responsible for this response?

Accepted Answer

Sympathetic nervous system

Question 17

Which of the following is true about the propagation of action potentials in myelinated axons?

Accepted Answer

Action potentials jump from one node of Ranvier to the next, increasing conduction speed.

Question 18

Which of the following best explains why the effect of a neurotransmitter at a synapse is short-lived?

Accepted Answer

Neurotransmitters are quickly broken down or taken back up by the presynaptic cell.

Question 19

Which of the following equations best represents the action of the sodium-potassium pump in neurons?

Accepted Answer

$$3\ \mathrm{Na}^+_{	ext{in}} + 2\ \mathrm{K}^+_{	ext{out}} + \mathrm{ATP} ightarrow 3\ \mathrm{Na}^+_{	ext{out}} + 2\ \mathrm{K}^+_{	ext{in}} + \mathrm{ADP} + \mathrm{P}$$

Neurons, Synapses, Signaling, and the Central Nervous System: Study Guide

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