Question 1

When an action potential arrives at an axon terminal, the fusion of neurotransmitter vesicles with the cell membrane is triggered by

Accepted Answer

A)  an increase in the concentration of calcium ions within the cell. 
B)  the removal of calcium ions from the cytoplasm of the cell. 
C)  the opening of K+ leak channels, which causes an increase in potassium ions within the cell. 
D)  the release of acetylcholine. 
E)  a sudden increase in chloride ions within the cytoplasm of the cell. 
A)  an increase in the concentration of calcium ions within the cell. 
B)  the removal of calcium ions from the cytoplasm of the cell. 
C)  the opening of K+ leak channels, which causes an increase in potassium ions within the cell. 
D)  the release of acetylcholine. 
E)  a sudden increase in chloride ions within the cytoplasm of the cell.

Question 2

Diseases such as multiple sclerosis and Guillain-Barre syndrome damage myelin.What is the common result of this damage?

Accepted Answer

A)  There are fewer astrocytes left to protect the axons. 
B)  Glial cells reproduce faster. 
C)  The blood-brain barrier becomes more permeable. 
D)  Conduction of action potentials is impaired. 
E)  The mitochondria within a neuron cannot function. 
A)  There are fewer astrocytes left to protect the axons. 
B)  Glial cells reproduce faster. 
C)  The blood-brain barrier becomes more permeable. 
D)  Conduction of action potentials is impaired. 
E)  The mitochondria within a neuron cannot function.

Question 3

When you recorded the membrane potential of a neuron, you noticed that the reading rapidly changed from -60 mV to +50 mV before returning to -60 mV again.What is a possible explanation for this event?

Accepted Answer

A)  An action potential 
B)  A graded potential 
C)  Hyperpolarization 
D)  Ionic current flow 
E)  Opening of leak channels 
A)  An action potential 
B)  A graded potential 
C)  Hyperpolarization 
D)  Ionic current flow 
E)  Opening of leak channels

Question 4

Once an action potential is initiated, there is a period that must elapse before Na+ channels can be activated again to generate another action potential.This is called the _______ period.

Accepted Answer

A)  membrane depolarization 
B)  membrane hyperpolarization 
C)  refractory 
D)  undershoot 
E)  after-hyperpolarization 
A)  membrane depolarization 
B)  membrane hyperpolarization 
C)  refractory 
D)  undershoot 
E)  after-hyperpolarization

Question 5

In a resting neuron, there is a difference in electrical charge across the cell membrane because

Accepted Answer

A)  voltage-gated channels in the membrane allow Na+ to enter the cell. 
B)  the concentration of Na+ is higher inside than outside the cell. 
C)  ion transporters require energy and are not active in a resting neuron. 
D)  K+ ions are pumped through channels until they reach equilibrium. 
E)  leak channels allow K+ ions to diffuse out of the cell. 
A)  voltage-gated channels in the membrane allow Na+ to enter the cell. 
B)  the concentration of Na+ is higher inside than outside the cell. 
C)  ion transporters require energy and are not active in a resting neuron. 
D)  K+ ions are pumped through channels until they reach equilibrium. 
E)  leak channels allow K+ ions to diffuse out of the cell.

Question 6

The drug pentylenetetrazole (PTZ) blocks the action of the neurotransmitter ______, which has been implicated in Down syndrome.

Accepted Answer

The answer of The drug pentylenetetrazole (PTZ) blocks the action...

Question 7

Which statement about electrical synapses is false?

Accepted Answer

A)  Electrical synapses do not perform temporal summation. 
B)  Signal transmission is rapid at electrical synapses. 
C)  Electrical synapses are mostly excitatory. 
D)  Electrical synapses are less common than chemical synapses in vertebrates. 
E)  Gap junctions are rare at electrical synapses. 
A)  Electrical synapses do not perform temporal summation. 
B)  Signal transmission is rapid at electrical synapses. 
C)  Electrical synapses are mostly excitatory. 
D)  Electrical synapses are less common than chemical synapses in vertebrates. 
E)  Gap junctions are rare at electrical synapses.

Question 8

Normally the acetylcholine receptor‒mediated channels in the motor end plate at a neuromuscular junction are closed.Which statement about this channel is true?

Accepted Answer

A)  The channel opens when acetylcholine passes through it. 
B)  The binding of acetylcholinesterase opens the channel. 
C)  Activation of the channel by the binding of acetylcholine causes Na+ ions to enter the presynaptic cell. 
D)  When the channel opens, Na+ ions enter the muscle cell. 
E)  When the channel opens, the cell becomes hyperpolarized. 
A)  The channel opens when acetylcholine passes through it. 
B)  The binding of acetylcholinesterase opens the channel. 
C)  Activation of the channel by the binding of acetylcholine causes Na+ ions to enter the presynaptic cell. 
D)  When the channel opens, Na+ ions enter the muscle cell. 
E)  When the channel opens, the cell becomes hyperpolarized.

Question 9

In the knee-jerk reflex circuit, the dorsal horn of the spinal cord contains the

Accepted Answer

A)  interneurons that connect sensory input to extensor muscle motor neurons. 
B)  stretch receptors. 
C)  cell bodies of motor neurons. 
D)  axons of sensory neurons. 
E)  white matter of the spinal cord. 
A)  interneurons that connect sensory input to extensor muscle motor neurons. 
B)  stretch receptors. 
C)  cell bodies of motor neurons. 
D)  axons of sensory neurons. 
E)  white matter of the spinal cord.

Question 10

Evaluate the following statement: A synapse at the tip of a dendrite has less influence than a synapse on the cell body when summation occurs at the axon hillock.

Accepted Answer

The statement is correct because postsyn

Exam 44: Neurons, Glia, and Nervous Systems

When an action potential arrives at an axon terminal, the fusion of neurotransmitter vesicles with the cell membrane is triggered by

Diseases such as multiple sclerosis and Guillain-Barre syndrome damage myelin.What is the common result of this damage?

When you recorded the membrane potential of a neuron, you noticed that the reading rapidly changed from -60 mV to +50 mV before returning to -60 mV again.What is a possible explanation for this event?

Once an action potential is initiated, there is a period that must elapse before Na+ channels can be activated again to generate another action potential.This is called the _______ period.

In a resting neuron, there is a difference in electrical charge across the cell membrane because

The drug pentylenetetrazole (PTZ) blocks the action of the neurotransmitter ______, which has been implicated in Down syndrome.

Which statement about electrical synapses is false?

Normally the acetylcholine receptor‒mediated channels in the motor end plate at a neuromuscular junction are closed.Which statement about this channel is true?

In the knee-jerk reflex circuit, the dorsal horn of the spinal cord contains the

Evaluate the following statement: A synapse at the tip of a dendrite has less influence than a synapse on the cell body when summation occurs at the axon hillock.

Studying Life

Small Molecules and the Chemistry of Life

Proteins, Carbohydrates, and Lipids

Nucleic Acids and the Origin of Life

Cells: the Working Units of Life

Cell Membranes

Cell Communication and Multicellularity

Energy, Enzymes, and Metabolism

Pathways That Harvest Chemical Energy

Photosynthesis: Energy From Sunlight

The Cell Cycle and Cell Division

Inheritance, Genes, and Chromosomes

Dna and Its Role in Heredity

From Dna to Protein: Gene Expression

Gene Mutation and Molecular Medicine

Regulation of Gene Expression

Genomes

Recombinant Dna and Biotechnology

Mechanisms of Evolution

Reconstructing and Using Phylogenies

Speciation

Evolution of Genes and Genomes

The History of Life on Earth

Bacteria, Archaea, and Viruses

The Origin and Diversification of Eukaryotes

Plants Without Seeds: From Water to Land

The Evolution of Seed Plants

The Evolution and Diversity of Fungi

Animal Origins and the Evolution of Body Plans

Protostome Animals

Deuterostome Animals

The Plant Body

Transport in Plants

Plant Nutrition

Regulation of Plant Growth

Reproduction in Flowering Plants

Plant Responses to Environmental Challenges

Physiology, Homeostasis, and Temperature Regulation

Animal Hormones

Immunology: Animal Defense Systems

Animal Reproduction

Animal Development

Sensory Systems

The Mammalian Nervous System: Structure and Higher Functions

Musculoskeletal Systems

Gas Exchange

Circulatory Systems

Nutrition, Digestion, and Absorption

Salt and Water Balance and Nitrogen Excretion

Animal Behavior

The Physical Environment and Biogeography of Life

Populations

Species Interactions

Communities

Ecosystems

A Changing Biosphere

Filters

Once an action potential is initiated, there is a period that must elapse before Na⁺ channels can be activated again to generate another action potential.This is called the _______ period.