Deck 7: The Nervous System: Neurons and Synapses

Question 1

A nerve is a bundle of axons in the CNS.

Answer 1

False

Question 2

Most motor neurons are multipolar.

Answer 2

True

Question 3

Somatic motor neurons innervate involuntary effectors.

Answer 3

False

Question 4

The nerve is the basic structural and functional unit of the nervous system.

Question 5

Which of the following is true of axons?

A)contain receptive areas
B)very thin and short
C)originates at the axon hillock on the cell body
D)transmits graded electrochemical impulses

Question 6

Sensory nerves regulate muscle contraction.

Question 7

Which of the following is NOT true of axonal transport?

A)uses molecular motors
B)can transport anteroretrograde
C)has one fast and two slow components
D)is a passive process

Question 8

Glial cells normally lose their mitotic ability prior to birth.

Question 9

Which of the following is NOT true of dendrites?

A)transmits action potentials toward the cell body
B)are thin extensions of the cell body
C)transmit graded electrochemical impulses toward the cell body
D)contain receptive areas

Question 10

The brain and spinal cord comprise the

A)central nervous system.
B)peripheral nervous system.
C)peripheral ganglia.
D)spinal nerves.

Question 11

Sensory neurons

A)are multipolar and carry impulses toward the CNS.
B)are pseudounipolar and carry impulses toward the CNS.
C)are bipolar and carry impulses away from the CNS.
D)are multipolar and carry impulses away from the CNS.

Question 12

Anteroretrograde transport uses dynein molecular motor proteins.

Question 13

Which of the following is NOT a structural classification of neurons?

A)motor neuron
B)bipolar neuron
C)multipolar neuron
D)pseudomultipolar neuron

Question 14

Axonal transport from the cell body to the dendrites and axon is retrograde transport.

Question 15

Retrograde axonal transport may be responsible for movement of herpes virus,rabies virus,and tetanus toxin from nerve terminals to the cell body.

Question 16

Which division of the nervous system innervates involuntary effectors?

A)central nervous system
B)somatic nervous system
C)autonomic nervous system
D)associative nervous system

Question 17

Retrograde transport

A)moves toward the cell body.
B)moves membranes,vesicles,and viruses.
C)uses molecular motor proteins of dynein.
D)All of the choices are correct.

Question 18

Which of the following is NOT a functional classification of neurons?

A)motor or efferent
B)interneuron or association
C)multipolar
D)sensory or afferent

Question 19

Ganglia are clusters of nerve cell bodies located in the peripheral nervous system.

Question 20

What type of neuron is found entirely in the CNS?

A)sensory neuron
B)interneuron
C)association neuron
D)Both interneuron and association neuron are correct.

Question 21

Fetal neuron growth requires the actions of a group of chemicals known as

A)endorphins.
B)synapsins.
C)neurotrophins.
D)glutamates.

Question 22

Axonal regeneration is inhibited by

A)brain-derived neurotrophic factor.
B)nerve growth factor.
C)neurotrophin-3.
D)myelin-associated inhibitory protein.

Question 23

All axons in the PNS are surrounded by Schwann cells.

Question 24

Which of the following is NOT a function of astrocytes?

A)can take up NT from a synapse
B)can stimulate or inhibit neurons
C)needed to form synapses in the CNS
D)phagocytose foreign material in the CNS
E)forms the blood-brain barrier

Question 25

The myelin sheaths of CNS neurons are produced by

A)Schwann cells.
B)oligodendrocytes.
C)ependymal cells.
D)leukocytes.

Question 26

Degeneration of spinal motor neurons in adults may be due to a lack of ____________ factor.

A)brain-derived neurotrophic (BDNF)
B)neurotrophin-3
C)nerve growth (NGF)
D)glial-derived neurotrophic (GDNF)

Question 27

The myelin sheaths of PNS neurons are produced by

A)Schwann cells.
B)oligodendrocytes.
C)ependymal cells.
D)leukocytes.

Question 28

A bundle of axons in the CNS is called a/an

A)nerve.
B)bundle.
C)tract.
D)neuron.

Question 29

Action potential transmission in the PNS is decreased if which cells are damaged?

A)astrocytes
B)microglia
C)oligodendrocytes
D)Schwann cells

Question 30

The most numerous of all cells of CNS nervous tissue are the

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

Question 31

Myelinated axons transmit action potentials more rapidly than unmyelinated axons.

Question 32

Schwann cells and oligodendrocytes have similar functions.

Question 33

What structure is found around PNS axons that is NOT found around CNS axons?

A)nodes of Ranvier
B)myelin sheath
C)neurilemma
D)plasma membrane

Question 34

The gap of exposed axon in the myelin sheath is the

A)neurilemmA.
B)node of Ranvier.
C)sheath of Schwann.
D)white matter.

Question 35

The disease ______________ is characterized by destruction of CNS myelin sheaths and the formation of hardened scars.

A)Parkinson's
B)Alzheimer's
C)multiple sclerosis.
D)myasthenia gravis

Question 36

Regeneration of CNS axons may be prevented in part by inhibitory proteins in the membranes of the

A)myelin sheath.
B)neurons.
C)astrocytes.
D)satellite cells.

Question 37

Destruction of astrocytes would decrease the rate at which action potentials are transmitted.

Question 38

White matter is

A)myelinated axons in the CNS.
B)myelinated axons in the PNS.
C)nonmyelinated cell bodies and dendrites in the CNS.
D)nonmyelinated axons in the CNS.

Question 39

Cells supporting neuron cell bodies in ganglia are termed

A)astrocytes.
B)ependymal cells.
C)satellite cells.
D)Schwann cells.

Question 40

Which of the following is NOT a function of neurotrophins?

A)maintaining sympathetic ganglion
B)sustain neurons that use the NT dopamine
C)embryonic development of neurons
D)regeneration of injured motor neurons

Question 41

The membrane of resting nerve cells is more permeable to ____________ ions than ____________ ions.

A)sodium,potassium
B)calcium,potassium
C)potassium,sodium
D)chloride,potassium

Question 42

Nerve cells depolarize due to the influx of K⁺.

Question 43

The blood-brain barrier may prevent medications from reaching brain tissue.

Question 44

Blocking ____________ channels would prevent neuronal depolarization.

A)K⁺
B)Cl^-
C)Na⁺
D)Mg²⁺

Question 45

All cells have a membrane potential.

Question 46

The mechanism that allows many Na⁺ ions to move into the axon is

A)negative feedback.
B)positive feedback.
C)equilibrium feedback.
D)None of the choices are correct.

Question 47

The blood-brain barrier prevents hydrophobic molecules from diffusing into the brain.

Question 48

The minimum depolarization needed to open Na⁺ gates is called the

A)repolarization.
B)threshold.
C)refractory period.
D)All-or-none law.

Question 49

An axon will depolarize only if the membrane potential reaches between -70mV and -55mV.This follows the

A)All-or-none law.
B)recruitment law.
C)graduated law.
D)threshold law.

Question 50

Cells become more negative during hyperpolarization.

Question 51

Astrocytes can be excited by changes in intracellular Ca²⁺ concentration.

Question 52

The average resting membrane potential of a neuron is -85mV.

Question 53

During the absolute refractory period,a supramaximal stimulus can bring the cell to threshold.

Question 54

The blood-brain barrier results mostly from the action of __________,a type of glial cell.

A)ependymal cells
B)microglia
C)astrocytes
D)oligodendrocytes

Question 55

Excitable cells are incapable of maintaining a constant resting membrane potential.

Question 56

Which cells are needed for the formation of synapses in the CNS?

A)ependymal
B)microglia
C)astrocytes
D)dendrites

Question 57

Ion channels that open in response to depolarization are called

A)ion-gated channels.
B)voltage-gated channels.
C)stimulation-gated channels.
D)potential-gated channels.

Question 58

Local anesthetics block conduction of action potentials in sensory neurons by

A)inhibiting the release of acetylcholine.
B)binding to potassium channels.
C)binding to sodium channels.
D)binding to calcium channels.

Question 59

Action potentials frequency encodes stimulus intensity.

Question 60

During an action potential

A)Na⁺ efflux causes depolarization.
B)K⁺ influx causes repolarization.
C)Na⁺ influx causes depolarization.
D)K⁺ influx causes after-hyperpolarization.

Question 61

Conduction without decrement means that action potentials transmitted down an axon will not decrease in amplitude.

Question 62

The ability of a neuron to transmit charge through its cytoplasm is called cable properties and is very

A)good.
B)strong.
C)poor.
D)easy.

Question 63

What type of proteins are present in gap junctions that form water-filled channels between neurons?

A)connexons
B)myelin
C)terminal boutons
D)cell adhesion molecules (CAMs)

Question 64

The period of time when Na⁺ channels are recovering from their inactive state and K⁺ channels are still open is the

A)repolarization.
B)absolute refractory period.
C)relative refractory period.
D)Both repolarization and relative refractory period are correct.

Question 65

Which ion's movements is responsible for repolarization?

A)influx of K+
B)influx of Na+
C)outward diffusion of K+
D)outward diffusion of Na+

Question 66

Most synapses in the body are electrical.

Question 67

What is NOT true of the relative refractory period?

A)Na+ channels are inactivated
B)many Na+ channels are returning to a closed state
C)K+ is moving out of the axon through its open channels
D)a strong stimulus could cause a depolarization

Question 68

______ synapses occur between axons of presynaptic cells and dendrites of postynaptic cells.

A)Axodendritic
B)Axosomatic
C)Myoneural
D)Axoaxonic

Question 69

Chemical synapses

A)have a delayed impulse transmission.
B)utilize gap junctions.
C)occur when two nerve cells are in direct contact with each other.
D)do not require the release of neurotransmitters.

Question 70

What coding system do neurons use to get a greater response?

A)greater amplitude of stimuli
B)greater Na+ concentration gradient
C)increased frequency of stimuli
D)more active Na+/K+ pump

Question 71

What process is needed to return a membrane to its resting membrane potential with all ions in the correct locations?

A)after-hyperpolarization
B)all-or-none-law
C)Na+/K+ pump
D)refractory period

Question 72

As the intensity of a stimulus increases,more axons will become activated.This process is called

A)threshold.
B)refraction.
C)recruitment.
D)None of the choices is correct.

Question 73

In a myelinated axon,Na⁺ channels are

A)along the whole length of the axon.
B)every 5 mm.
C)concentrated at the nodes of Ranvier.
D)less numerous at the nodes of Ranvier.

Question 74

Chemicals that stimulate action potentials in postsynaptic cells are called

A)hormones.
B)enzymes.
C)neurotransmitters.
D)neurotrophins.

Question 75

Conduction of an action potential in a myelinated axon is called

A)point to point conduction.
B)saltatory conduction.
C)refractory conduction.
D)cable conduction.

Question 76

The greater the number of depolarization regions on an axon,the faster the action potential will be conducted.

Question 77

Action potentials would be conducted most rapidly by

A)a 10 mm diameter myelinated axon.
B)a 10 mm diameter unmyelinated axon.
C)a 40 mm diameter myelinated axon.
D)a 40 mm diameter unmyelinated axon.

Question 78

Sensory neurons for muscle position are the fastest conducting neurons.

Question 79

Electrical synapses are functionally linked by tight junctions.

Question 80

An inactivated ion channel will respond to a strong stimulus.