Question 1

What would be the result of damage to the region of a neuron called the axon hillock?

Accepted Answer

The axon hillock integrates in

Question 2

Myasthenia gravis is an autoimmune disease in which a person's immune system attacks the receptors for acetylcholine at neuromuscular junctions.Why might physicians prescribe drugs that inhibit acetylcholinesterase to patients with this condition?

Accepted Answer

Drugs that inhibit acetylcholi

Question 3

Which statement about axons is false?

Accepted Answer

A)  Invertebrates rely on increasing axon diameter to increase conduction speed. 
B)  In vertebrates, myelination of axons is one way to increase conduction speed. 
C)  When an axon is myelinated, action potentials can only be fired at the nodes. 
D)  Voltage-gated ion channels are clustered at the nodes of myelinated axons. 
E)  Saltatory conduction is fast because ion channels open and close faster than electric current can flow through the cytoplasm. 
A)  Invertebrates rely on increasing axon diameter to increase conduction speed. 
B)  In vertebrates, myelination of axons is one way to increase conduction speed. 
C)  When an axon is myelinated, action potentials can only be fired at the nodes. 
D)  Voltage-gated ion channels are clustered at the nodes of myelinated axons. 
E)  Saltatory conduction is fast because ion channels open and close faster than electric current can flow through the cytoplasm.

Question 4

If you were seated on a postsynaptic cell waiting to receive an action potential from another neuron, which part(s) of the presynaptic cell would be closest?

Accepted Answer

A)  Axon 
B)  Axon terminals 
C)  Dendrites 
D)  Cell body 
E)  Axon hillock 
A)  Axon 
B)  Axon terminals 
C)  Dendrites 
D)  Cell body 
E)  Axon hillock

Question 5

Refer to the figure showing a neuromuscular junction.   Which event is occurring at position 5?

Accepted Answer

A)  Acetylcholine molecules are entering the postsynaptic cell. 
B)  Ca2+ channels open after acetylcholine binding occurs. 
C)  Charged acetylcholine molecules cause a graded potential in the postsynaptic membrane. 
D)  The motor end plate is depolarized by the influx of Na+. 
E)  Acetylcholinesterase breaks down acetylcholine, and the channel closes again. 
A)  Acetylcholine molecules are entering the postsynaptic cell. 
B)  Ca2+ channels open after acetylcholine binding occurs. 
C)  Charged acetylcholine molecules cause a graded potential in the postsynaptic membrane. 
D)  The motor end plate is depolarized by the influx of Na+. 
E)  Acetylcholinesterase breaks down acetylcholine, and the channel closes again.

Question 6

Ganglia frequently come in pairs

Accepted Answer

A)  with one ganglion at each end of an animal. 
B)  with one ganglion controlling afferent neurons and the other controlling efferent neurons. 
C)  in animals that show bilateral symmetry. 
D)  with one ganglion controlling sensory neurons and the other controlling effectors. 
E)  in animals with simple behaviors such as contraction and relaxation. 
A)  with one ganglion at each end of an animal. 
B)  with one ganglion controlling afferent neurons and the other controlling efferent neurons. 
C)  in animals that show bilateral symmetry. 
D)  with one ganglion controlling sensory neurons and the other controlling effectors. 
E)  in animals with simple behaviors such as contraction and relaxation.

Question 7

Which statement about the axon hillock is false?

Accepted Answer

A)  The axon hillock is located at the base of the axon. 
B)  The cell membrane at the axon hillock is not insulated by glia. 
C)  The axon hillock has no voltage-gated Na+ channels. 
D)  When depolarized to threshold, the axon hillock fires an action potential. 
E)  The axon hillock is the location where summation takes place in most neurons. 
A)  The axon hillock is located at the base of the axon. 
B)  The cell membrane at the axon hillock is not insulated by glia. 
C)  The axon hillock has no voltage-gated Na+ channels. 
D)  When depolarized to threshold, the axon hillock fires an action potential. 
E)  The axon hillock is the location where summation takes place in most neurons.

Question 8

The opening and closing of single ion channels produces tiny electrical currents across the cell membrane, which can be measured by

Accepted Answer

A)  the Goldman equation. 
B)  patch clamping. 
C)  the Nernst equation. 
D)  the electrochemical gradient. 
E)  the resting potential. 
A)  the Goldman equation. 
B)  patch clamping. 
C)  the Nernst equation. 
D)  the electrochemical gradient. 
E)  the resting potential.

Question 9

Refer to the graphs showing action potentials occurring in response to multiple excitatory postsynaptic potentials (EPSPs).   In graph A, the action potential is due to

Accepted Answer

A)  the action of each EPSP, which raises the membrane potential above its threshold. 
B)  the spatial summation of several simultaneous EPSPs. 
C)  the number of synapses on the cell body. 
D)  the rapid succession of EPSPs at one synapse. 
E)  the lack of inhibitory synapses. 
A)  the action of each EPSP, which raises the membrane potential above its threshold. 
B)  the spatial summation of several simultaneous EPSPs. 
C)  the number of synapses on the cell body. 
D)  the rapid succession of EPSPs at one synapse. 
E)  the lack of inhibitory synapses.

Question 10

Slowing of early divisions of neuronal stem cells in the neural tube of a vertebrate embryo would result in

Accepted Answer

A)  fewer microglia. 
B)  a worsening of immune function. 
C)  fewer neuronal stem cells. 
D)  neurons without dendrites. 
E)  fewer blood-forming stem cells. 
A)  fewer microglia. 
B)  a worsening of immune function. 
C)  fewer neuronal stem cells. 
D)  neurons without dendrites. 
E)  fewer blood-forming stem cells.

Question 11

At electrical synapses, membrane proteins called connexins connect the cytoplasm of the two neurons.These structural features result in transmission being fast and _______.

Accepted Answer

The answer of At electrical synapses, membrane proteins called connexins...

Question 12

The electrical charge difference across a cell membrane at rest is called the

Accepted Answer

A)  electrochemical gradient. 
B)  voltage potential. 
C)  diffusion constant. 
D)  membrane potential. 
E)  action potential. 
A)  electrochemical gradient. 
B)  voltage potential. 
C)  diffusion constant. 
D)  membrane potential. 
E)  action potential.

Question 13

Refer to the table listing the functions of several parts of a neuron.   List the parts from top to bottom to correctly match the parts to their functions.

Accepted Answer

A)  Axon, cell body, axon terminal, axon hillock, dendrite 
B)  Axon hillock, cell body, dendrite, axon, axon terminal 
C)  Axon, axon hillock, dendrite, cell body, axon terminal 
D)  Axon hillock, synapse, axon terminal, axon, dendrite 
E)  Synapse, axon hillock, dendrite, cell body, axon terminal 
A)  Axon, cell body, axon terminal, axon hillock, dendrite 
B)  Axon hillock, cell body, dendrite, axon, axon terminal 
C)  Axon, axon hillock, dendrite, cell body, axon terminal 
D)  Axon hillock, synapse, axon terminal, axon, dendrite 
E)  Synapse, axon hillock, dendrite, cell body, axon terminal

Question 14

All of the following apply to the sodium-potassium pump in neurons except

Accepted Answer

A)  it requires ATP to work. 
B)  it moves potassium ions to the inside of the neuron and sodium ions to the outside. 
C)  it works against a concentration gradient. 
D)  it consists of an enzyme complex. 
E)  it relies on facilitated diffusion. 
A)  it requires ATP to work. 
B)  it moves potassium ions to the inside of the neuron and sodium ions to the outside. 
C)  it works against a concentration gradient. 
D)  it consists of an enzyme complex. 
E)  it relies on facilitated diffusion.

Question 15

The Goldman equation can be used to calculate the equilibrium membrane potential by considering the

Accepted Answer

A)  differences in neuron size. 
B)  number of K+ leak channels. 
C)  number of sodium-potassium pumps. 
D)  electrical charge carried by Na+ ions. 
E)  relative permeabilities of the membrane to all ions that can diffuse across. 
A)  differences in neuron size. 
B)  number of K+ leak channels. 
C)  number of sodium-potassium pumps. 
D)  electrical charge carried by Na+ ions. 
E)  relative permeabilities of the membrane to all ions that can diffuse across.

Question 16

A drug that blocks the GABA receptor

Accepted Answer

A)  increases the excitatory actions of GABA. 
B)  disrupts all pain sensation. 
C)  prevents skeletal muscle contraction. 
D)  improves learning ability in the mouse model of Down syndrome. 
E)  reduces release of enkephalins. 
A)  increases the excitatory actions of GABA. 
B)  disrupts all pain sensation. 
C)  prevents skeletal muscle contraction. 
D)  improves learning ability in the mouse model of Down syndrome. 
E)  reduces release of enkephalins.

Question 17

A new drug blocks the nicotinic receptors of acetylcholine.What will be the effect?

Accepted Answer

A)  Hyperpolarization of cardiac muscle 
B)  Enhanced modulation of pain sensation 
C)  Decreased motility of the smooth muscle of the gut 
D)  Enhanced skeletal muscle contraction 
E)  Increased heart rate 
A)  Hyperpolarization of cardiac muscle 
B)  Enhanced modulation of pain sensation 
C)  Decreased motility of the smooth muscle of the gut 
D)  Enhanced skeletal muscle contraction 
E)  Increased heart rate

Question 18

When voltage-gated K+ channels open in the cell membrane of a neuron, K+ moves

Accepted Answer

A)  into the cell, and the membrane becomes hyperpolarized. 
B)  into the cell, and the membrane becomes depolarized. 
C)  out of the cell, and the membrane becomes depolarized. 
D)  out of the cell, and the membrane becomes hyperpolarized. 
E)  through the leak channels, and leak channels for Na+ are opened. 
A)  into the cell, and the membrane becomes hyperpolarized. 
B)  into the cell, and the membrane becomes depolarized. 
C)  out of the cell, and the membrane becomes depolarized. 
D)  out of the cell, and the membrane becomes hyperpolarized. 
E)  through the leak channels, and leak channels for Na+ are opened.

Question 19

When exposed to bright light, the pupil in your eye constricts.This action does not require conscious information processing, which means

Accepted Answer

A)  it is voluntary. 
B)  it consists of complex neural networks. 
C)  it requires extensive input from the brain. 
D)  it is a reflex. 
E)  it is a simple learned response. 
A)  it is voluntary. 
B)  it consists of complex neural networks. 
C)  it requires extensive input from the brain. 
D)  it is a reflex. 
E)  it is a simple learned response.

Question 20

Acetylcholine is

Accepted Answer

A)  a neurotransmitter. 
B)  released by muscle cells at neuromuscular junctions in vertebrates. 
C)  found in electrical synapses. 
D)  released when there is a drop in the cytoplasmic concentration of Ca2+ ions. 
E)  released by endocytosis. 
A)  a neurotransmitter. 
B)  released by muscle cells at neuromuscular junctions in vertebrates. 
C)  found in electrical synapses. 
D)  released when there is a drop in the cytoplasmic concentration of Ca2+ ions. 
E)  released by endocytosis.

Exam 44: Neurons, Glia, and Nervous Systems

What would be the result of damage to the region of a neuron called the axon hillock?

Myasthenia gravis is an autoimmune disease in which a person's immune system attacks the receptors for acetylcholine at neuromuscular junctions.Why might physicians prescribe drugs that inhibit acetylcholinesterase to patients with this condition?

Which statement about axons is false?

If you were seated on a postsynaptic cell waiting to receive an action potential from another neuron, which part(s) of the presynaptic cell would be closest?

Refer to the figure showing a neuromuscular junction. Which event is occurring at position 5?

Ganglia frequently come in pairs

Which statement about the axon hillock is false?

The opening and closing of single ion channels produces tiny electrical currents across the cell membrane, which can be measured by

Refer to the graphs showing action potentials occurring in response to multiple excitatory postsynaptic potentials (EPSPs). In graph A, the action potential is due to

Slowing of early divisions of neuronal stem cells in the neural tube of a vertebrate embryo would result in

At electrical synapses, membrane proteins called connexins connect the cytoplasm of the two neurons.These structural features result in transmission being fast and _______.

The electrical charge difference across a cell membrane at rest is called the

Refer to the table listing the functions of several parts of a neuron. List the parts from top to bottom to correctly match the parts to their functions.

All of the following apply to the sodium-potassium pump in neurons except

The Goldman equation can be used to calculate the equilibrium membrane potential by considering the

A drug that blocks the GABA receptor

A new drug blocks the nicotinic receptors of acetylcholine.What will be the effect?

When voltage-gated K+ channels open in the cell membrane of a neuron, K+ moves

When exposed to bright light, the pupil in your eye constricts.This action does not require conscious information processing, which means

Acetylcholine is

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When voltage-gated K⁺ channels open in the cell membrane of a neuron, K⁺ moves