Question 1

The axons of most neurons contain just one type of sodium channel,but several types of potassium channels.

Accepted Answer

A) True 
 B)False  True

Question 2

If you experimentally increase the concentration of Na⁺ outside a cell while maintaining other ion concentrations as they were,what would happen to the cell's membrane potential?

Accepted Answer

A) The membrane potential would decrease. 
B) The membrane potential would increase. 
C) The membrane potential would be unaffected. 
D) The answer depends on the thermodynamic potential. 
A) The membrane potential would decrease. 
B) The membrane potential would increase. 
C) The membrane potential would be unaffected. 
D) The answer depends on the thermodynamic potential. B

Question 3

Most synapses found so far in the mammalian central nervous system (CNS)are classified as chemical rather than electrical.

Accepted Answer

A) True 
 B)False  True

Question 4

Which of the following statements about action potentials is false?

Accepted Answer

A) All action potentials for a given neuron are identical in magnitude. 
B) All action potentials for a given neuron are identical in duration. 
C) Action potentials are propagated down the length of the axon. 
D) Movement of ions during the action potential occurs mostly through the sodium pump. 
E) The frequency of action potentials,not their size,is the meaningful signal. 
A) All action potentials for a given neuron are identical in magnitude. 
B) All action potentials for a given neuron are identical in duration. 
C) Action potentials are propagated down the length of the axon. 
D) Movement of ions during the action potential occurs mostly through the sodium pump. 
E) The frequency of action potentials,not their size,is the meaningful signal.

Question 5

Figure 45.1
  
-Which letter in Figure 45.1 corresponds to a large efflux of K⁺ ions from the cell?

Accepted Answer

A) A 
B) B 
C) C 
D) D 
E) E 
A) A 
B) B 
C) C 
D) D 
E) E

Question 6

One of the complications of Alzheimer's is an interference with learning and memory.An effect of this disease should involve _____.

Accepted Answer

A) changes in the concentration of ions in the extracellular fluid surrounding neurons 
B) changes in myelination of axons 
C) changes to the chemical structure of neurotransmitters 
D) molecular and structural changes at synapses 
E) structural changes to ion channels in axons 
A) changes in the concentration of ions in the extracellular fluid surrounding neurons 
B) changes in myelination of axons 
C) changes to the chemical structure of neurotransmitters 
D) molecular and structural changes at synapses 
E) structural changes to ion channels in axons

Question 7

Figure 45.1
  
-Which letter on Figure 45.1 corresponds to a large influx of Na⁺ ions into the cell?

Accepted Answer

A) A 
B) B 
C) C 
D) D 
E) E 
A) A 
B) B 
C) C 
D) D 
E) E

Question 8

If a doctor attempts to trigger the patellar tendon reflex and a lack of response occurs,what are potential regions where pathology might exist?

Accepted Answer

A) the brain 
B) the knee 
C) the spinal cord 
D) the knee and spinal cord 
E) the knee and the brain 
A) the brain 
B) the knee 
C) the spinal cord 
D) the knee and spinal cord 
E) the knee and the brain

Question 9

A large meal is likely to result in activity in which set of nerves?

Accepted Answer

A) parasympathetic nerves 
B) somatic nerves 
C) sympathetic nerves 
D) both the somatic and sympathetic nerves 
A) parasympathetic nerves 
B) somatic nerves 
C) sympathetic nerves 
D) both the somatic and sympathetic nerves

Question 10

Neurotransmitter is released _____.

Accepted Answer

A) in response to an action potential depolarizing the presynaptic membrane 
B) when threshold potential is reached 
C) when enough voltage-gated sodium channels open 
A) in response to an action potential depolarizing the presynaptic membrane 
B) when threshold potential is reached 
C) when enough voltage-gated sodium channels open

Question 11

Figure 45.1
  
-Which letter on Figure 45.1 corresponds to the action of the sodium-potassium pump and potassium leak channels?

Accepted Answer

A) A 
B) B 
C) C 
D) D 
E) E 
A) A 
B) B 
C) C 
D) D 
E) E

Question 12

Which of the following ions is most likely to cross the plasma membrane of a resting neuron?

Accepted Answer

A) K⁺ 
B) Na⁺ 
C) Ca²⁺ 
D) Cl⁻ 
E) Mg²⁺ 
A) K⁺ 
B) Na⁺ 
C) Ca²⁺ 
D) Cl⁻ 
E) Mg²⁺

Question 13

How do myelin sheaths increase the speed with which action potentials are propagated along an axon?

Accepted Answer

A) They increase the permeability of Na⁺ ions in the plasma membrane. 
B) They amplify the action potential by increasing sodium influx along the entire distance of the neuron. 
C) They cause action potentials to "jump" down the axon rather than travel in a continuous path along every site on the axon. 
D) All of the above answers apply. 
A) They increase the permeability of Na⁺ ions in the plasma membrane. 
B) They amplify the action potential by increasing sodium influx along the entire distance of the neuron. 
C) They cause action potentials to "jump" down the axon rather than travel in a continuous path along every site on the axon. 
D) All of the above answers apply.

Question 14

Why do the action potentials of some axons move more quickly than those of other axons?

Accepted Answer

A) larger diameter 
B) Drugs that affect the activity of neurotransmitters 
C) the presence of a myelin sheath 
D) all of the above 
E) none of the above 
A) larger diameter 
B) Drugs that affect the activity of neurotransmitters 
C) the presence of a myelin sheath 
D) all of the above 
E) none of the above

Question 15

What type of neuron can exist entirely within the central nervous system (CNS)?

Accepted Answer

A) interneuron 
B) motor neuron 
C) sensory neuron 
D) interneuron and motor neuron 
E) interneuron,sensory neuron,and motor neuron 
A) interneuron 
B) motor neuron 
C) sensory neuron 
D) interneuron and motor neuron 
E) interneuron,sensory neuron,and motor neuron

Question 16

If you experimentally increase the concentration of K⁺ inside a cell while maintaining other ion concentrations as they were,what would happen to the cell's membrane potential?

Accepted Answer

A) The membrane potential would become more negative. 
B) The membrane potential would become less negative. 
C) The membrane potential would remain the same. 
A) The membrane potential would become more negative. 
B) The membrane potential would become less negative. 
C) The membrane potential would remain the same.

Question 17

If twice as many inhibitory postsynaptic potentials (IPSPs)as excitatory postsynaptic potentials (EPSPs)arrive at a postsynaptic neuron in close proximity,is the integration of signals by the postsynaptic neuron likely to produce an action potential?

Accepted Answer

A) Yes 
B) No 
A) Yes 
B) No

Question 18

The concentrations of ions are very different inside and outside a nerve cell due to _____.

Accepted Answer

A) osmosis 
B) diffusion 
C) sodium-potassium pumps 
D) symports and antiports 
A) osmosis 
B) diffusion 
C) sodium-potassium pumps 
D) symports and antiports

Question 19

How could you increase the magnitude of inhibitory postsynaptic potentials (IPSPs)generated at a synapse?

Accepted Answer

A) increase sodium-potassium pump activity 
B) increase K⁺ permeability 
C) increase the influx of calcium 
D) All of the above apply. 
A) increase sodium-potassium pump activity 
B) increase K⁺ permeability 
C) increase the influx of calcium 
D) All of the above apply.

Question 20

The depolarization phase of an action potential requires _____.

Accepted Answer

A) opening of K⁺ channels in the membrane 
B) opening of Na⁺ channels in the membrane 
C) opening of Ca²⁺ channels in the membrane 
D) a K⁺ concentration gradient across the membrane 
E) a Ca²⁺ concentration gradient across the membrane 
A) opening of K⁺ channels in the membrane 
B) opening of Na⁺ channels in the membrane 
C) opening of Ca²⁺ channels in the membrane 
D) a K⁺ concentration gradient across the membrane 
E) a Ca²⁺ concentration gradient across the membrane

Exam 45: Electrical Signals in Animals

The axons of most neurons contain just one type of sodium channel,but several types of potassium channels.

If you experimentally increase the concentration of Na⁺ outside a cell while maintaining other ion concentrations as they were,what would happen to the cell's membrane potential?

Most synapses found so far in the mammalian central nervous system (CNS)are classified as chemical rather than electrical.

Which of the following statements about action potentials is false?

Figure 45.1 -Which letter in Figure 45.1 corresponds to a large efflux of K⁺ ions from the cell?

One of the complications of Alzheimer's is an interference with learning and memory.An effect of this disease should involve _____.

Figure 45.1 -Which letter on Figure 45.1 corresponds to a large influx of Na⁺ ions into the cell?

If a doctor attempts to trigger the patellar tendon reflex and a lack of response occurs,what are potential regions where pathology might exist?

A large meal is likely to result in activity in which set of nerves?

Neurotransmitter is released _____.

Figure 45.1 -Which letter on Figure 45.1 corresponds to the action of the sodium-potassium pump and potassium leak channels?

Which of the following ions is most likely to cross the plasma membrane of a resting neuron?

How do myelin sheaths increase the speed with which action potentials are propagated along an axon?

Why do the action potentials of some axons move more quickly than those of other axons?

What type of neuron can exist entirely within the central nervous system (CNS)?

If you experimentally increase the concentration of K⁺ inside a cell while maintaining other ion concentrations as they were,what would happen to the cell's membrane potential?

If twice as many inhibitory postsynaptic potentials (IPSPs)as excitatory postsynaptic potentials (EPSPs)arrive at a postsynaptic neuron in close proximity,is the integration of signals by the postsynaptic neuron likely to produce an action potential?

The concentrations of ions are very different inside and outside a nerve cell due to _____.

How could you increase the magnitude of inhibitory postsynaptic potentials (IPSPs)generated at a synapse?

The depolarization phase of an action potential requires _____.

Biology and the Tree of Life

Water and Carbon: the Chemical Basis of Life

Protein Structure and Function

Nucleic Acids and the Rna World

An Introduction to Carbohydrates

Lipids, membranes, and the First Cells

Inside the Cell

Cell-Cell Interactions

Cellular Respiration and Fermentation

Photosynthesis

The Cell Cycle

Meiosis

Mendel and the Gene

Dna and the Gene: Synthesis and Repair

How Genes Work

Transcription and Translation

Control of Gene Expression in Bacteria

Control of Gene Expression in Eukaryotes

Analyzing and Engineering Genes

Genomics

Principles of Development

An Introduction to Animal Development

An Introduction to Plant Development

Evolution by Natural Selection

Evolutionary Processes

Speciation

Phylogenies and the History of Life

Bacteria and Archaea

Protists

Green Plants

Fungi

An Introduction to Animals

Protostome Animals

Deuterostome Animals

Viruses

Plant Form and Function

Water and Sugar Transport in Plants

Plant Nutrition

Plant Sensory Systems, signals, and Responses

Plant Reproduction

Animal Form and Function

Water and Electrolyte Balance in Animals

Animal Nutrition

Gas Exchange and Circulation

Animal Sensory Systems and Movement

Chemical Signals in Animals

Animal Reproduction

The Immune System in Animals

An Introduction to Ecology

Behavioral Ecology

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