Question 1

The Nernst equation specifies the equilibrium potential for a particular ion.This equilibrium potential is a function of _____.

Accepted Answer

A) hydrostatic pressure 
B) ion concentration gradient 
C) osmotic gradient 
D) temperature (thermal)gradient 
E) the ion concentration gradient and the temperature (thermal)gradient 
A) hydrostatic pressure 
B) ion concentration gradient 
C) osmotic gradient 
D) temperature (thermal)gradient 
E) the ion concentration gradient and the temperature (thermal)gradient

Question 2

If a patient has an injury in the brain stem,which of the following would be observed?

Accepted Answer

A) auditory hallucinations 
B) visual hallucinations 
C) an inability to regulate body temperature 
D) an inability to regulate heart function 
A) auditory hallucinations 
B) visual hallucinations 
C) an inability to regulate body temperature 
D) an inability to regulate heart function

Question 3

Which of the following manipulations would reduce the release of neurotransmitter from a presynaptic neuron terminal?

Accepted Answer

A) reduction in extracellular calcium ion concentration at the axon terminal 
B) increase in extracellular sodium and potassium ion concentrations at the axon terminal 
C) addition of tetrodotoxin to the extracellular fluid at the axon terminal 
D) All of the above manipulations would reduce the release of neurotransmitter. 
A) reduction in extracellular calcium ion concentration at the axon terminal 
B) increase in extracellular sodium and potassium ion concentrations at the axon terminal 
C) addition of tetrodotoxin to the extracellular fluid at the axon terminal 
D) All of the above manipulations would reduce the release of neurotransmitter.

Question 4

If the activity of the sodium-potassium pump were changed by palytoxin (a toxin derived from coral)what would happen to the neuron's membrane potential?

Accepted Answer

A) immediate loss of resting potential 
B) immediate loss of action potentials 
C) slow decrease of resting potential 
D) no effect 
A) immediate loss of resting potential 
B) immediate loss of action potentials 
C) slow decrease of resting potential 
D) no effect

Question 5

A neurophysiologist is investigating nerve reflexes in two different animals a crab and a fish.Action potentials are found to pass more rapidly along the fish's neurons.What is the most likely explanation?

Accepted Answer

A) The fish's axons are smaller in diameter;small axons transmit action potentials faster than large axons do. 
B) Unlike the crab,the fish's axons are wrapped in myelin. 
C) There are more ion channels in the axons of the crab compared with fish axons. 
D) Unlike the crab,the fish's axons are wrapped in myelin,and the fish's axons are smaller in diameter;small axons transmit action potentials faster than large axons do. 
A) The fish's axons are smaller in diameter;small axons transmit action potentials faster than large axons do. 
B) Unlike the crab,the fish's axons are wrapped in myelin. 
C) There are more ion channels in the axons of the crab compared with fish axons. 
D) Unlike the crab,the fish's axons are wrapped in myelin,and the fish's axons are smaller in diameter;small axons transmit action potentials faster than large axons do.

Question 6

Patients with dysautonomia (autonomic nervous system disorders)will show symptoms in all of the following except _____.

Accepted Answer

A) airway diameter 
B) contraction of skeletal muscles 
C) heart rate 
D) pupil dilation and constriction 
E) stomach activity 
A) airway diameter 
B) contraction of skeletal muscles 
C) heart rate 
D) pupil dilation and constriction 
E) stomach activity

Question 7

Upon witnessing a robber hold up a convenience store at gunpoint,which of the following reactions would your nervous system initiate?

Accepted Answer

A) increased heartbeat 
B) constriction of airways 
C) constriction of pupils 
D) decreased heartbeat 
A) increased heartbeat 
B) constriction of airways 
C) constriction of pupils 
D) decreased heartbeat

Question 8

Why do Na⁺ ions enter the cell when voltage-gated Na⁺ channels are opened in neurons?

Accepted Answer

A) because the Na⁺ concentration is much higher outside the cell than it is inside 
B) because the Na⁺ ions are attracted to the negatively charged interior 
C) because the Na⁺ ions are actively transported by the sodium-potassium pump into the cell 
D) because the Na⁺ concentration is much higher outside the cell than it is inside,and the Na⁺ ions are attracted to the negatively charged interior 
E) because the Na⁺ concentration is much higher outside the cell than it is inside,and the Na⁺ ions are actively transported by the sodium-potassium pump into the cell 
A) because the Na⁺ concentration is much higher outside the cell than it is inside 
B) because the Na⁺ ions are attracted to the negatively charged interior 
C) because the Na⁺ ions are actively transported by the sodium-potassium pump into the cell 
D) because the Na⁺ concentration is much higher outside the cell than it is inside,and the Na⁺ ions are attracted to the negatively charged interior 
E) because the Na⁺ concentration is much higher outside the cell than it is inside,and the Na⁺ ions are actively transported by the sodium-potassium pump into the cell

Question 9

Tetrodotoxin blocks voltage-gated sodium channels and ouabain blocks sodium-potassium pumps.If you added both tetrodotoxin and ouabain to a solution containing neural tissue,what responses would you expect?

Accepted Answer

A) immediate loss of resting potential 
B) immediate loss of action potential with gradual loss of resting potential 
C) slow decrease of resting potential and action potential amplitudes 
D) no effect;the substances counteract each other 
A) immediate loss of resting potential 
B) immediate loss of action potential with gradual loss of resting potential 
C) slow decrease of resting potential and action potential amplitudes 
D) no effect;the substances counteract each other

Question 10

What would probably happen if a long neuron had one continuous myelin sheath down the length of the axon with no nodes of Ranvier?

Accepted Answer

A) The action potential would be propagated nearly instantaneously to the synapse. 
B) There could be no action potential generated at the axon hillock. 
C) The signal would fade because it is not renewed by the opening of more sodium channels. 
D) None of the above could happen. 
A) The action potential would be propagated nearly instantaneously to the synapse. 
B) There could be no action potential generated at the axon hillock. 
C) The signal would fade because it is not renewed by the opening of more sodium channels. 
D) None of the above could happen.

Question 11

Stem cell transplants may someday be used to treat Parkinson's disease.Researchers are hopeful that these cells would alleviate the symptoms of Parkinson's disease by _____.

Accepted Answer

A) preventing temporal lobe seizures 
B) repairing sites of traumatic brain injury 
C) replenishing missing ion channels 
D) secreting the neurotransmitter dopamine 
E) preventing temporal lobe seizures and secreting the neurotransmitter dopamine 
A) preventing temporal lobe seizures 
B) repairing sites of traumatic brain injury 
C) replenishing missing ion channels 
D) secreting the neurotransmitter dopamine 
E) preventing temporal lobe seizures and secreting the neurotransmitter dopamine

Question 12

Motor neurons release the neurotransmitter acetylcholine (ACh)and acetylcholinesterase degrades ACh in the synapse.If a neurophysiologist applies onchidal (a naturally occurring acetylcholinesterase inhibitor produced by the mollusk Onchidella binneyi)to a synapse,what would you expect to happen?

Accepted Answer

A) paralysis of muscle tissue 
B) gradual loss of resting potential 
C) convulsions due to constant muscle stimulation 
D) decrease in the frequency of action potentials 
E) no effect 
A) paralysis of muscle tissue 
B) gradual loss of resting potential 
C) convulsions due to constant muscle stimulation 
D) decrease in the frequency of action potentials 
E) no effect

Question 13

In multiple sclerosis the myelin sheaths around the axons of the brain and spinal cord are damaged and demyelination results.How does this disease manifest at the level of the action potential?

Accepted Answer

A) Action potentials move in the opposite direction on the axon. 
B) Action potentials move more slowly along the axon. 
C) Action potentials are entirely negated. 
D) All of the above occurs in multiple sclerosis. 
A) Action potentials move in the opposite direction on the axon. 
B) Action potentials move more slowly along the axon. 
C) Action potentials are entirely negated. 
D) All of the above occurs in multiple sclerosis.

Exam 45: Electrical Signals in Animals

The Nernst equation specifies the equilibrium potential for a particular ion.This equilibrium potential is a function of _____.

If a patient has an injury in the brain stem,which of the following would be observed?

Which of the following manipulations would reduce the release of neurotransmitter from a presynaptic neuron terminal?

If the activity of the sodium-potassium pump were changed by palytoxin (a toxin derived from coral)what would happen to the neuron's membrane potential?

A neurophysiologist is investigating nerve reflexes in two different animals a crab and a fish.Action potentials are found to pass more rapidly along the fish's neurons.What is the most likely explanation?

Patients with dysautonomia (autonomic nervous system disorders)will show symptoms in all of the following except _____.

Upon witnessing a robber hold up a convenience store at gunpoint,which of the following reactions would your nervous system initiate?

Why do Na⁺ ions enter the cell when voltage-gated Na⁺ channels are opened in neurons?

Tetrodotoxin blocks voltage-gated sodium channels and ouabain blocks sodium-potassium pumps.If you added both tetrodotoxin and ouabain to a solution containing neural tissue,what responses would you expect?

What would probably happen if a long neuron had one continuous myelin sheath down the length of the axon with no nodes of Ranvier?

Stem cell transplants may someday be used to treat Parkinson's disease.Researchers are hopeful that these cells would alleviate the symptoms of Parkinson's disease by _____.

Motor neurons release the neurotransmitter acetylcholine (ACh)and acetylcholinesterase degrades ACh in the synapse.If a neurophysiologist applies onchidal (a naturally occurring acetylcholinesterase inhibitor produced by the mollusk Onchidella binneyi)to a synapse,what would you expect to happen?

In multiple sclerosis the myelin sheaths around the axons of the brain and spinal cord are damaged and demyelination results.How does this disease manifest at the level of the action potential?

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

Population Ecology

Community Ecology

Ecosystems

Biodiversity and Conservation Biology

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