Question 1

An axon terminal of one neuron comes very close to the membrane of its target cell.The gap between the neuron and the target cell is called a

Accepted Answer

A)  dendrite. 
B)  nerve. 
C)  neurotransmitter. 
D)  barrier. 
E)  synaptic cleft. 
A)  dendrite. 
B)  nerve. 
C)  neurotransmitter. 
D)  barrier. 
E)  synaptic cleft.

Question 2

Which of the following does not characterize an electrochemical gradient across a membrane?

Accepted Answer

A)  It depends on the ion concentration gradient. 
B)  It depends on the voltage difference across the membrane. 
C)  It is a force acting on ions. 
D)  It determines the direction and amount of net movement of ions through ion channels. 
E)  It is unaffected by gates on channels. 
A)  It depends on the ion concentration gradient. 
B)  It depends on the voltage difference across the membrane. 
C)  It is a force acting on ions. 
D)  It determines the direction and amount of net movement of ions through ion channels. 
E)  It is unaffected by gates on channels.

Question 3

If you were looking through a microscope at a thin cross section of the neural tube from a very young vertebrate embryo, which cells might you see?

Accepted Answer

A)  Neuroblasts and gliablasts 
B)  Muscle cells 
C)  Microglia 
D)  Blood-forming stem cells 
E)  Bone and cartilage cells 
A)  Neuroblasts and gliablasts 
B)  Muscle cells 
C)  Microglia 
D)  Blood-forming stem cells 
E)  Bone and cartilage cells

Question 4

Refer to the graph showing the tracing of membrane potential change during the course of an action potential.   Which event is occurring in the section of the tracing highlighted in red?

Accepted Answer

A)  Closing of sodium channel inactivation gates 
B)  Opening of voltage-gated sodium channel activation gates 
C)  Closing of potassium leak channels 
D)  Opening of gated potassium channels 
E)  Closing of all gated channels 
A)  Closing of sodium channel inactivation gates 
B)  Opening of voltage-gated sodium channel activation gates 
C)  Closing of potassium leak channels 
D)  Opening of gated potassium channels 
E)  Closing of all gated channels

Question 5

The acetylcholine receptor is restored to its normal closed position by

Accepted Answer

A)  diffusion of excess acetylcholine out of the synapse. 
B)  movement of Na+ ions into the muscle cell. 
C)  movement of Na+ ions out of the muscle cell. 
D)  exocytosis of acetylcholine. 
E)  the activity of acetylcholinesterase. 
A)  diffusion of excess acetylcholine out of the synapse. 
B)  movement of Na+ ions into the muscle cell. 
C)  movement of Na+ ions out of the muscle cell. 
D)  exocytosis of acetylcholine. 
E)  the activity of acetylcholinesterase.

Question 6

Which statement about the withdrawal response to stepping on a piece of broken glass is false?

Accepted Answer

A)  The withdrawal reflex involves a simpler neural circuit than does the knee-jerk reflex. 
B)  In the withdrawal reflex, sensory neurons transmit action potentials into the dorsal horn of the spinal cord. 
C)  Some interneurons coordinate withdrawal of the foot with the actions of muscles associated with shifting weight to the other leg. 
D)  The reflex by which the foot is withdrawn is a polysynaptic spinal reflex. 
E)  Some interneurons send pain information to the brain. 
A)  The withdrawal reflex involves a simpler neural circuit than does the knee-jerk reflex. 
B)  In the withdrawal reflex, sensory neurons transmit action potentials into the dorsal horn of the spinal cord. 
C)  Some interneurons coordinate withdrawal of the foot with the actions of muscles associated with shifting weight to the other leg. 
D)  The reflex by which the foot is withdrawn is a polysynaptic spinal reflex. 
E)  Some interneurons send pain information to the brain.

Question 7

Morphine reduces pain because it is an _______ that potentiates the effects of _______.

Accepted Answer

A)  agonist; endorphins 
B)  antagonist; acetylcholine 
C)  antagonist; GABA 
D)  agonist; substance P 
E)  antagonist; nitric oxide 
A)  agonist; endorphins 
B)  antagonist; acetylcholine 
C)  antagonist; GABA 
D)  agonist; substance P 
E)  antagonist; nitric oxide

Question 8

If you step on a sharp tack, sensory receptors in your foot will stimulate action potentials to be sent via sensory neurons into the spinal cord.The sensory neurons will synapse with several different interneurons there to

Accepted Answer

A)  give you the idea of moving your foot. 
B)  cause the withdrawal reflex and give the sensation of pain. 
C)  cause a monosynaptic spinal reflex. 
D)  produce the sensation of pain on one side of your body and the withdrawal reflex on the other. 
E)  trigger a muscle reflex from information carried through afferent neurons. 
A)  give you the idea of moving your foot. 
B)  cause the withdrawal reflex and give the sensation of pain. 
C)  cause a monosynaptic spinal reflex. 
D)  produce the sensation of pain on one side of your body and the withdrawal reflex on the other. 
E)  trigger a muscle reflex from information carried through afferent neurons.

Question 9

The tripartite synapse model is the idea that the synapse includes presynaptic neurons, postsynaptic neurons, and _______.

Accepted Answer

The answer of The tripartite synapse model is the idea...

Question 10

Which event would make it less likely for a postsynaptic muscle cell to fire an action potential?

Accepted Answer

A)  Failure of Ca2+ to trigger exocytosis in the axon terminal of the presynaptic motor neuron 
B)  Inhibition of acetylcholinesterase in the synaptic cleft 
C)  Opening of voltage-gated Na+ channels and entrance of Na+ into the cell 
D)  Binding of acetylcholine to its receptors in the motor end plate 
E)  An increase in excitatory inputs 
A)  Failure of Ca2+ to trigger exocytosis in the axon terminal of the presynaptic motor neuron 
B)  Inhibition of acetylcholinesterase in the synaptic cleft 
C)  Opening of voltage-gated Na+ channels and entrance of Na+ into the cell 
D)  Binding of acetylcholine to its receptors in the motor end plate 
E)  An increase in excitatory inputs

Question 11

In vertebrates, most synapses are chemical, which means that information is transferred from one neuron to the next via

Accepted Answer

A)  neurotransmitters. 
B)  glucose. 
C)  myelin. 
D)  glycogen. 
E)  direct physical contact. 
A)  neurotransmitters. 
B)  glucose. 
C)  myelin. 
D)  glycogen. 
E)  direct physical contact.

Question 12

Because birds have forelimbs specialized for flight, most rely on their beaks to build nests.Controlling for body size, you might expect bird species that build nests requiring complex beak movements and fine motor control to have a larger _______ than bird species that build nests requiring only simple movements.

Accepted Answer

A)  posterior ganglion 
B)  olfactory lobe 
C)  brainstem 
D)  cerebellum 
E)  nerve net 
A)  posterior ganglion 
B)  olfactory lobe 
C)  brainstem 
D)  cerebellum 
E)  nerve net

Question 13

One way to prevent a sensory stimulus, such as pressure, from being received by the nervous system is to chemically block

Accepted Answer

A)  pressure receptors in the brain. 
B)  efferent neurons carrying information to muscles. 
C)  graded potentials in interneurons. 
D)  afferent neurons that connect with the sensory cells that detect pressure. 
E)  neurotransmitter release in the brain. 
A)  pressure receptors in the brain. 
B)  efferent neurons carrying information to muscles. 
C)  graded potentials in interneurons. 
D)  afferent neurons that connect with the sensory cells that detect pressure. 
E)  neurotransmitter release in the brain.

Question 14

Which statement about the ganglia of invertebrates is true?

Accepted Answer

A)  They are found in animals whose neural networks are characterized by little or no integration of information. 
B)  Paired ganglia are present primarily in radially symmetrical organisms. 
C)  Paired ganglia are found in the nerve nets of cnidarians. 
D)  They are found primarily in organisms with nerve nets. 
E)  A large set of fused ganglia at the anterior end of an organism is a brain. 
A)  They are found in animals whose neural networks are characterized by little or no integration of information. 
B)  Paired ganglia are present primarily in radially symmetrical organisms. 
C)  Paired ganglia are found in the nerve nets of cnidarians. 
D)  They are found primarily in organisms with nerve nets. 
E)  A large set of fused ganglia at the anterior end of an organism is a brain.

Question 15

As part of the peripheral nervous system, efferent neurons transmit information to

Accepted Answer

A)  sensory receptors. 
B)  effectors such as muscles and glands. 
C)  the nervous system. 
D)  axon terminals. 
E)  transducing cells. 
A)  sensory receptors. 
B)  effectors such as muscles and glands. 
C)  the nervous system. 
D)  axon terminals. 
E)  transducing cells.

Question 16

Refer to the graph showing the course of an action potential.   At which of the numbered points along the graph do voltage-gated sodium channels first open, and what is the result?

Accepted Answer

Some voltage-gated s

Question 17

Which statement concerning graded potentials is true?

Accepted Answer

A)  They are equivalent to the resting potential of the cell membrane. 
B)  They travel long distances to generate an action potential. 
C)  They are important in all sensory systems except neuromuscular junctions. 
D)  They allow a cell to integrate inputs and respond proportionally. 
E)  They are caused by ionic currents spreading over long distances. 
A)  They are equivalent to the resting potential of the cell membrane. 
B)  They travel long distances to generate an action potential. 
C)  They are important in all sensory systems except neuromuscular junctions. 
D)  They allow a cell to integrate inputs and respond proportionally. 
E)  They are caused by ionic currents spreading over long distances.

Question 18

Neurons have different shapes and sizes depending on their roles.A bipolar cell in the retina of the eye collects information from a few inputs and transmits it a short distance to one or more closely spaced neurons.What shape would you predict it to have?

Accepted Answer

A)  A few dendrites and a short axon with one or more terminals 
B)  A long axon with many axon terminals 
C)  A dense field of dendrites and a single axon 
D)  Numerous dendrites and a long axon 
E)  Dendrites and a highly branched axon 
A)  A few dendrites and a short axon with one or more terminals 
B)  A long axon with many axon terminals 
C)  A dense field of dendrites and a single axon 
D)  Numerous dendrites and a long axon 
E)  Dendrites and a highly branched axon

Question 19

The area where a neuron comes extremely close to a target cell and transmits information to the target cell is

Accepted Answer

A)  the ganglion. 
B)  the axon hillock. 
C)  the synapse. 
D)  the node of Ranvier. 
E)  insulated with myelin. 
A)  the ganglion. 
B)  the axon hillock. 
C)  the synapse. 
D)  the node of Ranvier. 
E)  insulated with myelin.

Question 20

Which statement about chemical synapses is false?

Accepted Answer

A)  At chemical synapses, action potentials in the axon terminal of a presynaptic neuron cause the release of neurotransmitters. 
B)  At chemical synapses, target cells can be other neurons, muscle cells, or secretory cells. 
C)  Unlike electrical synapses in which action potentials pass directly between two neurons, chemical synapses rely on neurotransmitters to pass information from a presynaptic neuron to a postsynaptic (target) cell. 
D)  At a chemical synapse, the binding of neurotransmitter to its receptor always excites the postsynaptic (target) cell. 
E)  At a chemical synapse, neurotransmitters diffuse across the synaptic cleft (space) and bind to receptors on the postsynaptic (target) cell. 
A)  At chemical synapses, action potentials in the axon terminal of a presynaptic neuron cause the release of neurotransmitters. 
B)  At chemical synapses, target cells can be other neurons, muscle cells, or secretory cells. 
C)  Unlike electrical synapses in which action potentials pass directly between two neurons, chemical synapses rely on neurotransmitters to pass information from a presynaptic neuron to a postsynaptic (target) cell. 
D)  At a chemical synapse, the binding of neurotransmitter to its receptor always excites the postsynaptic (target) cell. 
E)  At a chemical synapse, neurotransmitters diffuse across the synaptic cleft (space) and bind to receptors on the postsynaptic (target) cell.

Exam 44: Neurons, Glia, and Nervous Systems

An axon terminal of one neuron comes very close to the membrane of its target cell.The gap between the neuron and the target cell is called a

Which of the following does not characterize an electrochemical gradient across a membrane?

If you were looking through a microscope at a thin cross section of the neural tube from a very young vertebrate embryo, which cells might you see?

Refer to the graph showing the tracing of membrane potential change during the course of an action potential. Which event is occurring in the section of the tracing highlighted in red?

The acetylcholine receptor is restored to its normal closed position by

Which statement about the withdrawal response to stepping on a piece of broken glass is false?

Morphine reduces pain because it is an _______ that potentiates the effects of _______.

If you step on a sharp tack, sensory receptors in your foot will stimulate action potentials to be sent via sensory neurons into the spinal cord.The sensory neurons will synapse with several different interneurons there to

The tripartite synapse model is the idea that the synapse includes presynaptic neurons, postsynaptic neurons, and _______.

Which event would make it less likely for a postsynaptic muscle cell to fire an action potential?

In vertebrates, most synapses are chemical, which means that information is transferred from one neuron to the next via

One way to prevent a sensory stimulus, such as pressure, from being received by the nervous system is to chemically block

Which statement about the ganglia of invertebrates is true?

As part of the peripheral nervous system, efferent neurons transmit information to

Refer to the graph showing the course of an action potential. At which of the numbered points along the graph do voltage-gated sodium channels first open, and what is the result?

Which statement concerning graded potentials is true?

Neurons have different shapes and sizes depending on their roles.A bipolar cell in the retina of the eye collects information from a few inputs and transmits it a short distance to one or more closely spaced neurons.What shape would you predict it to have?

The area where a neuron comes extremely close to a target cell and transmits information to the target cell is

Which statement about chemical synapses is false?

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

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A Changing Biosphere

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Morphine reduces pain because it is an _ that potentiates the effects of _.