Unformatted text preview: Human Anatomy & Physiology, 7e (Marieb)
Chapter 11 Fundamentals of the Nervous System and Nervous Tissue
MATCHING QUESTIONS Figure 11.1
Using Figure 11.1, match the following:
1) Which neuron would connect to a muscle?
Diff: 1 Page Ref: Tbl. 11.1 2) Which neuron would be found in the retina of the eye?
Diff: 1 Page Ref: Tbl. 11.1 3) Which neuron is a sensory neuron found in a reflex arc?
Diff: 1 Page Ref: Tbl. 11.1 4) Which neuron is never myelinated?
Diff: 1 Page Ref: Tbl. 11.1 5) Which neuron is rare?
Diff: 1 Page Ref: 395 6) In a reflex arc, which neuron has its cell body inside the spinal cord?
Diff: 1 Page Ref: 396; Tbl. 11.1 7) Which neuron is common only in dorsal root ganglia of the spinal cord and sensory ganglia of cranial
Diff: 1 Page Ref: 395 8) Which is by far the most common neuron type?
Diff: 1 Page Ref: 395 Figure 11.2
Using Figure 11.2, match the following:
9) Ion channel.
Diff: 1 Page Ref: 410; Fig. 11.18 10) Synaptic vesicles.
Diff: 1 Page Ref: 410; Fig. 11.18 11) Calcium ions.
Diff: 3 Page Ref: 410; Fig. 11.18 12) Postsynaptic membrane.
Diff: 1 Page Ref: 410; Fig. 11.18 13) Synaptic cleft.
Diff: 1 Page Ref: 410; Fig. 11.18 Match the following:
14) Neurotransmitters are released at
Diff: 1 A) Dendrites B) Axon terminal
Page Ref: 409 C) Nissl bodies
15) The rough ER of the cell.
Diff: 1 Page Ref: 391 16) Receptive region of the neuron.
Diff: 1 Page Ref: 393 17) Conducting region of the
Diff: 1 Page Ref: 393 D) Axon Match the following:
18) Period during which the neuron
cannot respond to a second
stimulus, no matter how strong. A) Relative refractory period B) Repolarization
Diff: 1 C) Depolarization
Page Ref: 406 D) Action potential
19) The interior of the cell becomes
less negative due to an influx of
E) Absolute refractory period
Diff: 1 Page Ref: 400-402 20) The specific period during
which potassium ions diffuse
out of the neuron due to a
change in membrane
Diff: 1 Page Ref: 404 21) Also called a nerve impulse
transmitted by axons.
Diff: 1 Page Ref: 402 22) An exceptionally strong
stimulus can trigger a response.
Diff: 1 Page Ref: 406 Match the following:
23) Numerous nerve impulses
arriving at a synapse at closely
timed intervals exert a
cumulative effect. A) Spatial summation B) Threshold stimulus
Diff: 1 C) Temporal summation
Page Ref: 412; Fig. 11.20 D) Subthreshold stimulus
24) Stimulation of a postsynaptic
neuron by many terminals at the
Diff: 1 Page Ref: 412; Fig. 11.20 25) An insufficient stimulus.
Diff: 1 Page Ref: 405; Fig.11.14 26) Any stimulus below this
intensity will result in no
response in a neuron.
Diff: 2 Page Ref: 405; Fig.11.14 TRUE/FALSE QUESTIONS
1) The all-or-none phenomenon as applied to nerve conduction states that the whole nerve cell must be
stimulated for conduction to take place.
Diff: 1 Page Ref: 406 2) Reflexes are rapid, automatic responses to stimuli.
Diff: 1 Page Ref: 423 3) Efferent nerve fibers may be described as motor nerve fibers.
Diff: 1 Page Ref: 388 4) Saltatory conduction occurs because of the presence of salt (NaCl) around the neuron.
Diff: 1 Page Ref: 407; Fig. 11.16 5) Cell bodies of sensory neurons may be located in ganglia lying outside the central nervous system.
Diff: 1 Page Ref: 395 6) Myelination of the nerve fibers in the central nervous system is the job of the oligodendrocyte.
Diff: 1 Page Ref: 391 7) During depolarization, the inside of the neuron's membrane becomes less negative.
Diff: 1 Page Ref: 400 8) Neurons in the CNS are organized into functional groups.
Diff: 1 Page Ref: 395-421 9) Strong stimuli cause the amplitude of action potentials generated to increase.
Diff: 1 Page Ref: 406 10) The oligodendrocytes can myelinate several axons.
Diff: 1 Page Ref: 391 11) Enkephalins and endorphins are peptides that act like morphine.
Diff: 1 Page Ref: 418 12) A synapse formed between the axon ending of one neuron and the cell body of another neuron is
called an axosomatic synapse.
Diff: 1 Page Ref: 408-409 13) In myelinated axons the voltage-regulated sodium channels are concentrated at the nodes of Ranvier.
Diff: 1 Page Ref: 394 14) Action potentials can be generated by virtually all cells of the body because all cells possess cell
Diff: 1 Page Ref: 397 15) Voltage is always measured between two points and may be called the potential between these two
Diff: 1 Page Ref: 397 16) Neurons that are far away from the center of the neuron pool and that are not easily excited by an
incoming stimulus are in the discharge zone.
Diff: 1 Page Ref: 421 17) Acetylcholine is not a biogenic amine.
Diff: 1 Page Ref: 417-418 18) The two major classes of graded potentials are transmitter potentials and receptor potentials.
Diff: 2 Page Ref: 401 19) A graded potential that is the result of a neurotransmitter released into the synapse between two
neurons is called a postsynaptic potential.
Diff: 2 Page Ref: 401 20) Large-diameter nerve fibers conduct impulses much faster than small-diameter fibers.
Diff: 2 Page Ref: 407 21) The nodes of Ranvier are found only on myelinated, peripheral neural processes.
Diff: 2 Page Ref: 394-395 22) Unipolar neurons have axons structurally divided into peripheral and central processes.
Diff: 2 Page Ref: 395-396 23) A stimulus traveling toward a synapse appears to open calcium channels at the presynaptic end, which
in turn promotes fusion of synaptic vesicles to the axonal membrane.
Diff: 3 Page Ref: 409-410 24) A positive feedback cycle is the main force in the generation of graded potentials at receptor ends.
Diff: 3 Page Ref: 401 25) If bacteria invaded the CNS tissue, microglia would migrate to the area to engulf and destroy them.
Diff: 3 Page Ref: 391 MULTIPLE-CHOICE QUESTIONS
1) Direct-acting neurotransmitters ________.
A) require cyclic AMP
B) mediate very slow responses
C) open ion channels to provoke rapid responses
D) act through second messengers
Diff: 1 Page Ref: 409 2) Which of the following is correct relative to Ohm's law?
A) I = R / V
B) Current is directly proportional to the voltage.
C) R = V + I
D) The more intense the stimulus, the more voltage changes.
Diff: 1 Page Ref: 398 3) Ciliated CNS neuroglia that play an active role in moving the cerebrospinal fluid are called ________.
A) ependymal cells
B) Schwann cells
Diff: 1 Page Ref: 391 4) The sheath of Schwann is also called the ________.
A) myelin sheath
D) white matter
Diff: 1 Page Ref: 394 5) Bipolar neurons are commonly ________.
A) motor neurons
B) called neuroglial cells
C) found in ganglia
D) found in the retina of the eye
Diff: 1 Page Ref: 395 6) An excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle is ________.
D) gamma aminobutyric acid
Diff: 1 Page Ref: 415, 417 7) A neural circuit in which a single impulse is transmitted over and over is a ________.
A) diverging circuit
B) converging circuit
C) reverberating circuit
D) repetitive circuit
Diff: 1 Page Ref: 422 8) The period after an initial stimulus when a neuron is not sensitive to another stimulus is the ________.
A) resting period
D) absolute refractory period
Diff: 1 Page Ref: 406 9) A neuronal circuit that concentrates or directs a large number of incoming impulses to a rather small
number of neurons is called a(n) ________.
A) diverging circuit
B) oscillating circuit
C) converging circuit
D) parallel circuit
Diff: 1 Page Ref: 421-422 10) Which of the following is not a structural feature of a neuron?
A) synaptic cleft
B) Nissl bodies
Diff: 1 Page Ref: 391-393, 409 11) The part of a neuron that conducts impulses away from its cell body is called a(n) ________.
D) Schwann cell
Diff: 1 Page Ref: 393 12) The chemically gated channel, NMDA, allows ________ ions entry into the nerve cell.
A) Na+ B) K+
D) ClAnswer: C
Diff: 1 Page Ref: 412-413 13) The point at which an impulse from one nerve cell is communicated to another nerve cell is the
A) cell body
Diff: 1 Page Ref: 409 14) The role of acetylcholinesterase is to ________.
A) act as a transmitting agent
B) amplify or enhance the effect of ACh
C) destroy ACh a brief period after its release by the axonal endings
D) stimulate the production of serotonin
Diff: 1 Page Ref: 415, 417 15) Which of the following is not a function of the autonomic nervous system?
A) innervation of smooth muscle of the digestive tract
B) innervation of cardiac muscle
C) innervation of glands
D) innervation of skeletal muscle
Diff: 1 Page Ref: 388 16) Collections of nerve cell bodies outside the central nervous system are called ________.
Diff: 1 Page Ref: 392 17) The term central nervous system refers to the ________.
A) autonomic nervous system
B) brain, spinal cord, and peripheral nerves
C) brain and spinal cord
D) spinal cord and spinal nerves
Diff: 1 Page Ref: 388 18) The substance released at axon terminals to propagate a nervous impulse is called a(n) ________.
D) biogenic amine
Diff: 1 Page Ref: 409-410 19) A neuron that has as its primary function the job of connecting other neurons is called a(n) ________.
A) efferent neuron
B) afferent neuron
C) association neuron D) glial cell
Diff: 2 Page Ref: 395-397 20) Saltatory conduction is made possible by ________.
A) the myelin sheath
B) large nerve fibers
C) diphasic impulses
D) erratic transmission of nerve impulses
Diff: 1 Page Ref: 407 21) Which of these ions is actively transported through the cell membrane to establish a resting potential?
Diff: 1 Page Ref: 402 22) The part of the neuron that normally receives stimuli is called ________.
A) an axon
B) a dendrite
C) a neurolemma
D) a Schwann cell
Diff: 1 Page Ref: 393 23) Choose the statement that is most correct about membrane potential.
A) Voltage would be measured by placing two electrodes on the exterior of the axon.
B) Voltage would be measured by placing one electrode inside the membrane and another outside
C) Voltage would be measured by placing one electrode on one end of the axon and another
electrode on the other end.
D) Voltage would be measured by placing one electrode on the axon and grounding the other
Diff: 1 Page Ref: 399 24) The sodium-potassium pump ________.
A) pumps three sodium ions outside the cell and two potassium ions inside
B) pumps two sodium ions outside the cell and three potassium ions inside
C) pumps three sodium ions inside the cell and two potassium ions outside
D) pumps two sodium ions inside the cell and three potassium ions outside
Diff: 1 Page Ref: 399-400 25) An action potential ________.
A) is essential for impulse propagation
B) involves the influx of negative ions to depolarize the membrane
C) is initiated by potassium ion movement
D) involves impulse propagation dependent on chemically gated ion channels
Diff: 1 Page Ref: 402 26) Select the correct statement about synapses.
A) Cells with interconnected cytoplasm are chemically coupled.
B) The release of neurotransmitter molecules gives cells the property of being electrically coupled.
C) Neurotransmitter receptors are located on the axons of cells. D) The synaptic cleft prevents an impulse from being transmitted directly from one neuron to
Diff: 1 Page Ref: 409 27) Which of the following is a good example of a neuromodulator?
B) any protein
C) any carbohydrate
D) nitric oxide
Diff: 1 Page Ref: 419 28) Which group of fibers spreads impulses at up to 1 meter per second?
A) group A fibers
B) group B fibers
C) group C fibers
D) group D fibers
Diff: 1 Page Ref: 408 29) The sympathetic and parasympathetic are subdivisions of the ________.
A) central nervous system
B) voluntary nervous system
C) autonomic nervous system
D) somatic nervous system
Diff: 1 Page Ref: 388-389 30) Ependymal cells ________.
A) are a type of neuron
B) are a type of macrophage
C) are the most numerous of the neuroglia
D) help to circulate the cerebrospinal fluid
Diff: 1 Page Ref: 391 31) Neuroglia that control the chemical environment around neurons by buffering potassium and
recapturing neurotransmitters are ________.
D) Schwann cells
Diff: 1 Page Ref: 390 32) Schwann cells are functionally similar to ________.
A) ependymal cells
Diff: 1 Page Ref: 391 33) Immediately after an action potential has peaked, which cellular gates open?
Diff: 1 Page Ref: 404 34) Nerve cell adhesion molecules (N-CAMs) ________.
A) release nerve growth factor
B) are found on "pathfinder" neurons
C) are crucial in the production of neurotransmitters
D) are crucial for the development of neural connections
Diff: 1 Page Ref: 423-424 35) An inhibitory postsynaptic potential (IPSP) is associated with ________.
A) a change in sodium ion permeability
C) opening of voltage-regulated channels
D) lowering the threshold for an action potential to occur
Diff: 1 Page Ref: 412 36) Which of the following will occur when an excitatory postsynaptic potential (EPSP) is being
generated on the dendritic membrane?
A) Specific sodium gates will open.
B) Specific potassium gates will open.
C) Sodium gates will open first, then close as potassium gates open.
D) A single type of channel will open, permitting simultaneous flow of sodium and potassium.
Diff: 1 Page Ref: 411 37) When a sensory neuron is excited by some form of energy, the resulting graded potential is called a(n)
A) postsynaptic potential
B) excitatory potential
C) action potential
D) generator potential
Diff: 2 Page Ref: 401 38) All of the following are true of graded potentials except that they ________.
A) are short-lived
B) can form on receptor endings
C) increase amplitude as they move away from the stimulus point
D) can be called postsynaptic potentials
Diff: 2 Page Ref: 401-402 39) Which of the following is true about the movement of ions across excitable living membranes?
A) Ions always move actively across membranes through leakage channels.
B) Some ions are prevented from moving down their concentration gradients by ATP-driven
C) Sodium gates in the membrane can open in response to electrical potential changes.
D) The bulk of the solutions inside a cell are negatively charged.
Diff: 2 Page Ref: 399-400 40) ________ is an indolamine.
Diff: 2 Page Ref: 415, 418 41) A second nerve impulse cannot be generated until ________.
A) the membrane potential has been reestablished
B) the Na ions have been pumped back into the cell
C) proteins have been resynthesized
D) all sodium gates are closed
Diff: 3 Page Ref: 402 42) In what way does the interior surface of a cell membrane of a resting (nonconducting) neuron differ
from the external environment? The interior is ________.
A) positively charged and contains less sodium
B) negatively charged and contains less sodium
C) negatively charged and contains more sodium
D) positively charged and contains more sodium
Diff: 3 Page Ref: 399 43) If a motor neuron in the body were stimulated by an electrode placed about midpoint along the length
of the axon ________.
A) the impulse would move to the axon terminal only
B) muscle contraction would occur
C) the impulse would spread bidirectionally
D) the impulse would move to the axon terminal only, and the muscle contraction would occur
Diff: 3 Page Ref: 401 44) Neurons may be classified according to several characteristics. Which of the following is correct?
A) Group A fibers are mostly somatic sensory and motor and are the smallest in diameter.
B) Group B fibers are highly myelinated and have the highest conduction velocities.
C) Group C fibers are not capable of saltatory conduction.
D) A small cross-sectional area allows shorter conduction times.
Diff: 3 Page Ref: 408 45) Select the correct statement about serial processing.
A) Spinal reflexes are an example of serial processing.
B) Input travels along several different pathways.
C) Smells are processed by serial pathways.
D) Memories are triggered by serial processing.
Diff: 3 Page Ref: 422-423 FILL-IN-THE-BLANK/SHORT ANSWER QUESTIONS
1) That part of the nervous system that is voluntary and conducts impulses from the CNS to the skeletal
muscles is the ________ nervous system.
Diff: 1 Page Ref: 388 2) ________ are found in the CNS and bind axons and blood vessels to each other.
Diff: 1 Page Ref: 390 3) A gap between Schwann cells in the peripheral system is called a(n) ________.
Answer: node of Ranvier
Diff: 1 Page Ref: 394 4) ________ law is the relationship between voltage, current, and resistance.
Diff: 1 Page Ref: 398 5) The synapse more common in embryonic nervous tissue than in adults is the ________.
Answer: electrical synapse
Diff: 1 Page Ref: 408-409 6) When information is delivered within the CNS simultaneously by different parts of the neural
pathway, the process is called ________ processing.
Diff: 1 Page Ref: 423 7) ________ potentials are short-lived, local changes in membrane potential that can be either
depolarized or hyperpolarized.
Diff: 2 Page Ref: 401 8) ________ is a disease that gradually destroys the myelin sheaths of neurons in the CNS, particularly
in young adults.
Answer: Multiple sclerosis (MS)
Diff: 2 Page Ref: 407-408 9) When one or more presynaptic neurons fire in rapid order it produces a much greater depolarization of
the postsynaptic membrane than would result from a single EPSP; this event is called ________
Diff: 2 Page Ref: 412 10) ________ is a neurotransmitter of the CNS that is used by Purkinje cells of the CNS.
Answer: GABA (gamma aminobutyric acid)
Diff: 2 Page Ref: 418 11) Define neurotransmitter. Name two amino acid neurotransmitters, two catecholamines, and two
Answer: Neurotransmitters are chemical signals used as a means of communication. GABA and glycine
are amino acid neurotransmitters; dopamine and norepinephrine are catecholamines; and
endorphin and enkephalin are peptide transmitters.
Diff: 3 Page Ref: 413-419 12) What function is served by the increased axon diameter at the nodes of Ranvier?
Answer: Increased diameter results in increased surface area on the membrane for sodium channels.
This results in increased speed of impulse propagation.
Diff: 2 Page Ref: 407 13) Imagine a neuron that has several hundred axonal knobs impinging on it. The majority of these axonal
knobs are shown to be "firing." However, the neuron in question does not transmit an impulse. Give a
valid explanation of why this could occur.
Answer: Both excitatory and inhibitory potentials impinge on neurons. Inhibitory postsynaptic
potentials (IPSPs) are "firing," but due to the neurotransmitter released and its action, the
postsynaptic neuron is inhibited from "firing" (hyperpolarized).
Diff: 3 Page Ref: 411-412 14) Why does a hyperpolarization phase generally follow a repolarization phase in an action potential?
Answer: Immediately after an action potential the potassium gates, being slow gates which do not
respond to change in the electrical charge, allow additional K+ ions to flood into the cell.
These K+ ions decrease the positive ion concentration momentarily below the normal -70mV
and thus hyperpolarize the cell.
Diff: 3 Page Ref: 402, 404 15) What are the basic divisions of the peripheral nervous system?
Answer: Sensory and motor divisions. Motor has two divisions: the somatic and autonomic. The
autonomic has two divisions: the sympathetic and parasympathetic.
Diff: 1 Page Ref: 388-389 16) Since all action potentials are alike, how does the brain separate situations that require immediate
attention from ordinary "positional" reports?
Answer: The importance of a stimulus is derived from the number of stimuli received from the same
source. The frequency of impulse transmission indicates the stimulus intensity and the brain
Diff: 1 Page Ref: 405-406 17) How can a single axon respond to several different kinds of events?
Answer: Some axon terminals contain more than one kind of neurotransmitter. Therefore, the axon can
release one or more neurotransmitters simultaneously, creating singular or multiple events.
Diff: 1 Page Ref: 413-414 18) ATP neurotransmitters have what basic effect on the body?
Answer: They provoke a sensation of pain.
Diff: 1 Page Ref: 416; Tbl. 11.3 19) How can potentially poisonous gasses like NO and CO be used by the body?
Answer: These gasses are neurotransmitters that act indirectly. Similar to hormones, NO and CO
promote longer-lasting effects by acting through intracellular second-messenger molecules.
Diff: 3 Page Ref: 419 CLINICAL QUESTIONS
1) Multiple sclerosis (MS) is a disease in which the myelin sheaths are destroyed. What process does this
interfere with and what would be the consequence?
Answer: Demyelination interferes with saltatory conduction, which would result in a slowing down of
nerve impulse propagation.
Diff: 2 Page Ref: 407-408 2) A client is admitted to the hospital with exacerbation of multiple sclerosis (MS). She asks the
nurse,"Why did this have to happen to me again? I was doing so well." Explain why some forms of
MS are characterized by periods of remission and exacerbation.
Answer: Even though someone is diagnosed with MS, the axons are not damaged. Growing numbers of
sodium channels appear spontaneously in the demyelinated fibers so that conduction resumes,
even if slower. This may account for the cycles of relapse and remission in different patients.
Diff: 2 Page Ref: 407-408 3) A client was admitted for depression. What should the nurse explain to the client regarding the role of
serotonin and depression?
Answer: Serotonin is a biogenic amine neurotransmitter widely distributed in the brain, where it plays a
role in emotional behavior and helps to regulate the biological clock.
Diff: 3 Page Ref: 415, 418 4) What symptoms would a nurse focus on in his or her care of a client with multiple sclerosis?
Answer: Visual disturbances, paralysis, and weakness
Diff: 3 Page Ref: 407-408 ...
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