Saltatory Conduction Occurs Only if the Myelin Sheath is Continuous

1) Which of the following is a function of the motor division of the
nervous system?

A) providing sensation of the internal and external environments
B) integrating sensory information
C) coordinating voluntary and involuntary activities
D) sending signals to muscles
E) regulating or controlling peripheral structures and systems

sending signals to muscles
The ______ nervous system is subdivided into sensory and motor divisions and each of these is further subdivided into somatic and visceral subdivisions.

peripheral
List the three functional classes of neurons.
- 1. motor neurons
- 2. sensory neurons
- 3. interneurons
Motor or ______ neurons (indicated by the red arrow) carry signals away from the CNS and they lead to effectors (muscle and gland cells).

efferent
The sensory and motor divisions of the peripheral nervous system are further divided into ______ and ______ subdivisions.

somatic & visceral
Name the two organ systems dedicated to regulation of body function.
- Nervous System
- Endocrine System
The brain and spinal cord are components of the ______ nervous system. The nerves and ganglia are components of the ______ nervous system.
- Central
- Peripheral
Name the usually long process of a nerve fiber that generally conducts impulses away from the body of the nerve cell.

axon
An axon lacking a myelin sheath is said to be unmyelinated and signal conduction occurs when:

a wave of depolarization excites voltage-gated channels immediately distal to the action potential
List characteristics of neuroglia.
- - they protect neurons and help them function
- - they bind neurons together and provide a supportive scaffold
Explain how a neuron generates electrical signals.

Movement of ions through channels generate an electrical charge difference (voltage) across the membrane.
The brain and spinal cord comprise the

A) autonomic nervous system.
B) peripheral nervous system.
C) central nervous system.
D) efferent nervous system.
E) afferent nervous system.

central nervous system.
The three general functions of the nervous system are

A) sensory, motor, and predictive.
B) sensory, motor, and manipulative.
C) sensory, motor, and integrative.
D) reflexive, predictive, and motor.
E) emotion, memory, and movement.

sensory, motor, and integrative.
In general, the nervous system

A) controls everything.
B) is fast acting.
C) is long lasting.
D) responds to changes in the external environment only.
E) all of the above

is fast acting.
The part of the peripheral nervous system that brings information to the central nervous system is the

A) motor division.
B) afferent division.
C) efferent division.
D) autonomic division.
E) somatic division.

afferent division.
Most neurons in the brain are
A) bipolar.
B) unipolar.
C) anaxonic.
D) multipolar.
E) tripolar.

multipolar.
Neurons normally derive ATP solely through

A) aerobic respiration.
B) anaerobic respiration.
C) formation of creatine phosphate.
D) use of stored glycogen.
E) both A and D

aerobic respiration.
The glial cells responsible for maintaining the blood-brain barrier are the

A) astrocytes.
B) Schwann cells.
C) microglia.
D) ependymal cells.
E) fiber cells.

astrocytes.
The cytoplasmic extensions that, together with the cell body, provide the main receptive surfaces for neurons are the

A) axons.
B) soma.
C) synapses.
D) dendrites.
E) neurofibrils.

dendrites.
Which of the following is a function of neurons?

A) support
B) information processing
C) secretion of cerebrospinal fluid
D) isolation of neuroglia
E) phagocytosis

information processing
The largest and most numerous of the glial cells in the central nervous system are the

A) astrocytes.
B) Schwann cells.
C) oligodendrocytes.
D) microglia.
E) ependymal cells.

astrocytes.
The myelin sheaths that surround the axons of some of the neurons in the CNS are formed by

A) astrocytes.
B) Schwann cells.
C) oligodendrocytes.
D) microglia.
E) ependymal cells.

oligodendrocytes.
Which of the following is a glial cell?

A) astrocytes
B) Schwann cells
C) oligodendrocytes
D) microglia
E) all of the above

all of the above
Small phagocytic cells that are especially obvious in damaged tissue in the CNS are the

A) astrocytes.
B) Schwann cells.
C) oligodendrocytes.
D) microglia.
E) ependymal cells.

microglia.
The neurilemma of axons in the peripheral nervous system is formed by

A) astrocytes.
B) ependymal cells.
C) oligodendrocytes.
D) microglia.
E) Schwann cells.

Schwann cells.
Cells responsible for information processing and transfer are

A) neuroglia.
B) Schwann cells.
C) neurons.
D) astrocytes.
E) microglia.

neurons.
Aggregations of ribosomes in neurons are referred to as

A) neurofilaments.
B) neurofibrils.
C) synapses.
D) Nissl bodies.
E) microglia.

Nissl bodies.
Branches that sometimes occur along the length of an axon are called

A) action potentials.
B) synaptic knobs.
C) collaterals.
D) hillocks.
E) synapse.

collaterals.
Neurons that have one axon and one dendrite with the soma between them are called

A) polypolar.
B) unipolar.
C) bipolar.
D) tripolar.
E) multipolar.

unipolar.
Interneurons

A) are found only in the central nervous system.
B) carry only sensory impulses.
C) carry only motor impulses.
D) only connect motor neurons to other motor neurons.
E) are found between neurons and their effectors.

are found only in the central nervous system.
Most neurons lack centrioles. This observation explains
A) why neurons grow such long axons.
B) why these neurons cannot regenerate.
C) the conducting ability of neurons.
D) the ability of neurons to communicate with each other.
E) the ability of neurons to live long lives.

why these neurons cannot regenerate.
The polarization of a nerve fiber refers to having the
A) sodium and potassium ions inside the cell. B) sodium ions inside the cell and potassium outside the cell.
C) potassium ions inside the cell and sodium outside the cell.
D) chloride ions inside the cell.
E) hillock and knob at opposite ends.

potassium ions inside the cell and sodium outside the cell.
Saltatory conduction
A) occurs only if the myelin sheath is continuous.
B) occurs only if nodes of Ranvier are lacking. C) is faster than conduction on an unmyelinated axon.
D) is slower that conduction on an unmyelinated axon.
E) occurs at the synapse.

is faster than conduction on an unmyelinated axon.
The most rapid action potentials are conducted on
A) thick, myelinated axons.
B) thick, unmyelinated axons.
C) thin, myelinated axons.
D) thin, unmyelinated axons.
E) dendrites.

thick, myelinated axons.
Opening of sodium channels in the membrane of a neuron results in
A) depolarization.
B) repolarization.
C) hyperpolarization.
D) increased negative charge inside the membrane.
E) none of the above

depolarization.
he following are the main steps in the generation of an action potential.
1. Sodium channels are inactivated.
2. Potassium channels open and potassium moves out of the cell, initiating repolarization. 3. Sodium channels regain their normal properties.
4. A graded depolarization brings an area of an excitable membrane to threshold.
5. A temporary hyperpolarization occurs.
6. Sodium channel activation occurs.
7. Sodium ions enter the cell and depolarization occurs.

4, 6, 7, 1, 2, 3, 5
When a neuron is at rest, which ion passes through its membrane most easily?
A) sodium
B) chloride
C) sulfate
D) potassium
E) proteins

potassium
The all-or-none principle states that
A) all stimuli will produce identical action potentials.
B) all stimuli great enough to bring the membraneto threshold will produce identical action potentials.
C) the greater the magnitude of the stimuli, the greater the intensity of the action potential.
D) only sensory stimuli can activate action potentials.
E) only motor stimuli can activate action potentials.

all stimuli great enough to bring the membrane to threshold will produce identical action potentials.
During continuous conduction,
A) action potentials move in all directions along an axon.
B) action potentials occur at successive nodes along the length of the stimulated axon.
C) local currents depolarize adjacent areas of membrane so that action potentials continue to form along the membrane.
D) action potentials produce a local current that is strong enough to spread along the length of the axon.
E) local potentials produce a continuous outward flow of potassium ions.

local currents depolarize adjacent areas of membrane so that action potentials continue to form along the membrane.
If a resting potential becomes more negative, the cell
A) repolarizes.
B) hyperpolarizes.
C) depolarizes.
D) refracts.
E) summates.

hyperpolarizes.
A neuron that is excited to subthreshold is said to be
A) summed.
B) facilitated.
C) hyperpolarized.
D) converged.
E) graded.

facilitated.
Which of the following is a function of the brain interstitium?
A) provides cushioning for delicate neural tissues
B) provides buoyant support for the brain
C) acts as a transport medium for nutrients
D) provides a medium for nerve impulse transmission
E) acts as a transport medium for chemical messengers

provides a medium for nerve impulse transmission
If the sodium–potassium pumps in the plasma membrane fail to function,
A) the extracellular concentration of potassium ions will increase.
B) the intracellular concentration of sodium ions will increase.
C) the membrane will lose its capacity to generate action potentials.
D) the inside of the membrane will have a resting potential that is more positive than normal.
E) all of the above

all of the above
Tetrodotoxin is a toxin that blocks the sodium channels from opening. What effect would this have on the function of neurons?
A) Neurons would depolarize more rapidly.
B) Action potentials would lack a repolarization phase.
C) The refractory period would be shorter than normal.
D) The neurons would not be able to propagate action potentials.
E) none of the above

The neurons would not be able to propagate action potentials.
Synaptic knobs occur at the ends of
A) dendrites.
B) somas.
C) telodendria.
D) peduncles.
E) axons.

dendrites.
Neurotransmitters are released from the
A) dendrites.
B) synaptic terminals/knobs.
C) collaterals.
D) hillock.
E) synapse.

synaptic terminals/knobs.
Which type of synapse dominates the nervous system?
A) chemical
B) electrical
C) mechanical
D) processing
E) radioactive

chemical
The ion needed to initiate the release of acetylcholine into the synaptic cleft is
A) sodium.
B) potassium.
C) calcium.
D) chloride.
E) zinc.

calcium.
The processing of the same information at the same time by several neuronal pools is called
A) serial processing.
B) parallel processing.
C) divergent processing.
D) convergent processing.
E) facilitation.

parallel processing.
Which of the following lists the parts of a reflex arc in the correct order?
A) receptor, sensory neuron, interneuron, motor neuron, effector
B) receptor, effector, sensory neuron, interneuron, motor neuron
C) receptor, sensory neuron, effector, interneuron, motor neuron
D) effector, receptor, sensory neuron, interneuron, motor neuron
E) receptor, interneuron, sensory neuron, motor neuron, effector

receptor, sensory neuron, interneuron, motor neuron, effector
The specialized membranes that protect the spinal cord are termed
A) cranial meninges.
B) cranial mater.
C) spinal meninges.
D) spinal mater.
E) epidural membranes.

spinal meninges.
Blood vessels servicing the spinal cord are found in the
A) pia mater.
B) dura mater.
C) epidural space.
D) subdural space.
E) subarachnoid space.

pia mater.
The dural sinuses are located in the
A) dura mater.
B) arachnoid.
C) pia mater.
D) cortex.
E) subarachnoid space.

dura mater.
What contains a delicate network of collagen and elastin fibers through which cerebrospinal fluid circulates?
A) epidural space
B) dural sinus
C) arachnoid villi
D) subarachnoid space
E) pia mater

subarachnoid space
Diffusion across the arachnoid villi returns excess CSF to
A) the third ventricle.
B) arterial circulation.
C) venous circulation.
D) the fourth ventricle.
E) the central canal.

venous circulation.
Head injuries that damage cerebral blood vessels are serious conditions because
A) they could cause severe pain.
B) these spaces compress and distort the relatively soft tissues of the brain.
C) epicardial tissue will be affected.
D) the venous sinus will not drain.
E) pathways will be blocked.

these spaces compress and distort the relatively soft tissues of the brain.
The projections of gray matter toward the outer surface of the spinal cord are called
A) wings.
B) horns.
C) pyramids.
D) fibers.
E) tracts.

horns.
Masses of myelinated nerve fibers appear
A) gray.
B) white.
C) yellow.
D) brown.
E) transparent.

white.
Axons crossing from one side of the spinal cord to the other within the gray matter are found in the
A) anterior gray horns.
B) lateral gray horns.
C) posterior gray horns.
D) gray commissures.
E) white commissures.

gray commissures.
The white matter of the spinal cord contains A) bundles of axons that share common origins, destinations, and functions.
B) bundles of dendrites that share common origins, destinations, and functions.
C) sensory and motor nuclei.
D) both axons and dendrites.
E) interneurons.

bundles of axons that share common origins, destinations, and functions.
Enlargements of the spinal cord occur
A) near the posterior median sulcus.
B) adjacent to the anterior median fissure.
C) in segments of the spinal cord that control the limbs.
D) in the thoracic region of the spinal cord.
E) none of the above

in segments of the spinal cord that control the limbs.
The entire spinal cord is divided into ________ segments.
A) 5
B) 12
C) 25
D) 31
E) 35

31
The horns of the spinal cord contain
A) nerve tracts.
B) columns.
C) meninges.
D) nerve cell bodies.
E) all of the above

nerve cell bodies.
The posterior horns of the spinal cord contain A) sensory nuclei.
B) somatic motor nuclei.
C) autonomic motor nuclei.
D) nerve tracts.
E) all of the above

sensory nuclei.
Gray matter in the spinal cord is mostly
A) fissures.
B) cerebrospinal fluid.
C) interneurons.
D) axons.
E) myelin.

interneurons
If the dorsal root of a spinal nerve is severed,
A) motor control of skeletal muscles would be impaired.
B) motor control of visceral organs would be impaired.
C) the spinal cord would not be able to process information at that level.
D) the brain would not be able to communicate with that level of the spinal cord.
E) incoming sensory information would be disrupted.

incoming sensory information would be disrupted.
The part of the brain that functions to control skeletal muscles is the
A) medulla oblongata.
B) cerebral cortex.
C) midbrain.
D) diencephalons.
E) thalamus.

cerebral cortex.
The phrenic nerves arise from the
A) cervical plexus.
B) thoracic plexus.
C) lumbar plexus.
D) sacral plexus.
E) brain.

cervical plexus.
The area of skin supplied by sensory nerve fibers from a particular dorsal root is called a A) somite.
B) microtome.
C) dermatome.
D) sensory unit.
E) motor unit.

dermatome.
Nerves exit the vertebral canal through
A) vertebral foramen.
B) intervertebral foramen.
C) sacral foramen.
D) intervertebral discs.
E) both B and C

both B and C - intervertebral foramen, sacral foramen
There are ________ pairs of cranial nerves.
A) 6
B) 8
C) 10
D) 12
E) 31

12
The only cranial nerve that is attached to the cerebrum is the
A) optic.
B) oculomotor.
C) trochlear.
D) olfactory.
E) vestibulocochlear.

olfactory.
Damage to which of the following cranial nerves could result in death?
A) abducens
B) facial
C) glossopharyngeal
D) vagus
E) hypoglossal

vagus
Which of the following pairs is not properly matched?
A) cervical spinal nerves: 8
B) thoracic spinal nerves: 12
C) lumbar spinal nerves: 4
D) sacral spinal nerves: 5
E) coccygeal spinal nerves: 1

lumbar spinal nerves: 4
Muscles of the intercostal spaces are innervated by nerves from the
A) cervical region.
B) thoracic region.
C) lumbar region.
D) sacral region.
E) coccygeal region.

thoracic region.
Spinal nerves from the sacral region of the cord innervate
A) the shoulder muscles.
B) the chest muscles.
C) the abdominal muscles.
D) the leg muscles.
E) both C and D

the leg muscles.
The joining of adjacent spinal nerves is termed a
A) cranial nerve.
B) conjoined spinal nerve.
C) lateral nerve group.
D) tract.
E) plexus.

plexus.
Neural reflexes
A) are automatic motor responses.
B) are triggered by specific stimuli.
C) help preserve homeostasis.
D) show little variability in response.
E) all of the above

all of the above
Reflexes help to control
A) heart rate.
B) blood pressure.
C) digestion.
D) pupil size.
E) all of the above

all of the above
Pulling away from a painful stimulus is an example of the ________ reflex.
A) cross-extensor
B) pupillary
C) withdrawal
D) knee-jerk
E) ankle-jerk

withdrawal
The expected response to the triceps-jerk reflex is
A) the Babinski sign.
B) elbow flexion.
C) elbow extension.
D) plantar flexion.
E) arm extension.

elbow extension.
In which of the following would the delay between stimulus and response be greater?
A) a reflex that involves many synapses
B) a reflex that involves fewer synapses

a reflex that involves many synapses
An abnormal stretch response would indicate A) damage to the spinal cord.
B) damage to the stretch receptors.
C) damage to the nerve serving the area.
D) damage to the joint.
E) All of the above are possible, and more tests would be necessary.

All of the above are possible, and more tests would be necessary.
Another name for the patellar reflex is the
A) knee-jerk reflex.
B) spinal short reflex.
C) dorsiflexion reflex.
D) long spinal reflex.
E) none of the above

knee-jerk reflex.
Golgi tendon organs
A) are found in skeletal muscles.
B) are found within joint capsules.
C) are controlled through the cranial nerves. D) help prevent muscle damage that would result from overstretching.
E) both A and D

are found within joint capsules.
The flexor reflex
A) prevents a muscle from overstretching.
B) prevents a muscle from generating damaging tension.
C) moves a limb away from a painful stimulus.
D) makes adjustments in other parts of the body in response to a particular stimulus.
E) is an example of a monosynaptic reflex.

moves a limb away from a painful stimulus.
Bundles of axons in the spinal cord are called
A) nerves.
B) tracts.
C) centers.
D) nuclei.
E) ganglia.

tracts.
Ascending tracts
A) carry sensory information to the brain.
B) carry motor information to the brain.
C) carry sensory information from the brain. D) carry motor information from the brain.
E) none of the above

carry sensory information to the brain.
The spinal tract or pathway that carries highly localized sensory information concerning fine touch and pressure is (are) the
A) spinothalamic.
B) posterior column.
C) corticospinal pathway.
D) medial and lateral pathways.
E) spinocerebellar.

posterior column.
The most sensitive area of the body is the
A) chest.
B) face.
C) feet.
D) back.
E) legs.

face.
An autonomic motor neuron whose cell body lies in the CNS is called a(n)
A) upper motor neuron.
B) lower motor neuron.
C) preganglionic neuron.
D) postganglionic neuron.
E) somatic motor neuron.

preganglionic neuron.
Control of the viscera is the job of the
A) spinal cord.
B) conscious control.
C) brain.
D) autonomic nervous system.
E) all of the above

autonomic nervous system.
Control of glands is through the
A) PNS.
B) ANS.
C) SNS.
D) CNS.
E) RAS.

ANS.
The _________________________ division of the nervous system brings sensory information to the central nervous system.

afferent
The _________________________ of the neuron is the cell body.

soma
The gaps between adjacent Schwann cells along the length of an axon are called _________________________.

nodes
The minimum amount of stimulus required to depolarize an excitable membrane and generate an action potential is known as the _________________________.

threshold
The time during which an excitable membrane cannot respond to further stimulation is the _________________________.

refractory period
An action potential traveling along an axon is called a(n) _________________________.

nerve impulse
The layer of lipid around an axon is called _________________________.

myelin
When more than one stimulus is added together, it is called _________________________.

summation
The _________________________ is the layer of the meninges that is in direct contact with the surface of the brain.

pia mater
The fluid that surrounds and bathes the central nervous system is _________________________.

cerebrospinal fluid or CSF
The _________________________ nerve innervates the diaphragm.

phrenic
_________________________ reflexes involve skeletal muscles.

Somatic
When a neuron is stimulated, Na+ gates open and allow Na+ to exit the cell.

True/False

False
A greater stimulus will cause a greater peak in action potential

True/False

False
Electrical synapses are slower acting that chemical synapses

True/False

False
____ division carries signals to the smooth muscle in the large intestine.

Visceral motor
In the brain, neurons are more abundant than neuroglia.

True/False

False
Inhibitory postsynaptic potentials (IPSPs) are associated with
A) depolarization of the cell membrane.
B) repolarization of the cell membrane.
C) hyperpolarization of the cell membrane.
D) no change of the cell membrane potential.
E) no change of the threshold

hyperpolarization of the cell membrane.
The myelin sheath is formed by
A) Fibers
B) cells
C) macromolecules.
D) polymers.
E) organelles.

cells
Most neurons have multiple dendrites.

True/False

True
___ neurons are the most common type of neurons.

Multipolar
____ are the primary site for receiving signals from other neurons.

Dendrites
___ has the greatest influence on the resting membrane potential.

Potassium
Which of the following will cause the plasma membrane to hyperpolarize when at its RMP?

inflow of chloride
During the absolute refractory period

no stimulus of any strength will trigger a new action potential.
Multiple sclerosis is the result of:

CNS myelin degradation
Inter-neurons are only found in the central nervous system

True/False

True
This image shows an action potential. What does "6" represent?

repolarization of the membrane
Saltatory conduction is made possible by:
- Myelination,
- Schwann Cells
- Nodes of Ranvier
- Voltage gated Na+ channels
Nerve tracts can be regenerated

True/False

False
The blood brain barrier:

is an astrocyte function
For the interpretation for intensity, the central nervous system codes for frequency action potentials.

True/False

True
A ganglion is a swelling along a nerve containing cell bodies of peripheral neurons.

True/Fasle

True
A dermatome is a nerve innervating a specific region in the skin.

True/False

False
Posterior root ganglia contain somas of unipolar neurons.

True/False

True
Somatic reflexes are responses of skeletal, smooth and cardiac muscles.

True/False

False
The stretch reflex is a tendency of a muscle to stretch when it is overcontracted.

True/False

False
Spinal cord conducts signals up and down the body passing through gray and white matter, respectively.

True/False

False
Motor signals typically begin in an upper motor neuron in the thalamus.

True/False

False
You go to the movies after a long day and you begin to nod off as soon as the movie starts. Your head starts to lower a little but this reflex
causes your head to rise. This is called the:

stretch (myotatic) reflex.
The tendon reflex

prevents overcontraction of a muscle.
A nerve fiber is enclosed in its own fibrous sleeve called perineurium.

True/False

False
Which one of the following best describes the order of a somatic reflex?

somatic receptor > afferent nerve fiber > interneuron > efferent nerve fiber > skeletal muscle
These are all properties of reflexes except

reflexes are spontaneous actions of the nervous system.
Cerebrospinal fluid fills in the space between

arachnoid mater and pia mater.
The ventral rami of the spinal nerves form nerve plexuses in all regions except

the thoracic region.
Gray matter contains

neurosomas, dendrites, and proximal parts of axons of neurons.
Second-order neurons synapse with third-order neurons in the

thalamus.
The cervical plexus gives origin to the ___ nerve(s).

phrenic
A mixed nerve consists of both

afferent and efferent fibers.
Which of the following branches of a spinal nerve have somas of solely sensory neurons?

posterior (dorsal) root

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Source: https://freezingblue.com/flashcards/213547/preview/ch-12-13-questions

Saltatory Conduction Occurs Only if the Myelin Sheath is Continuous

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