anatomy Chapter 11 nervous tissue

7) The cytoplasm that surrounds the nucleus of a neuron is called the A) protoplasm. B) nucleoplasm. C) sarcoplasm. D) neuroplasm. E) perikaryon.

Perikaryon

11) Axons terminate in a series of fine extensions known as A) telodendria. B) knobs. C) collateral branches. D) dendrites. E) synapses.

Telodendria

80) Puffer fish poison blocks voltage-gated sodium channels like a cork. What effect would this neurotoxin have on the function of neurons? A) Neurons would depolarize more rapidly. B) Action potentials would lack a repolarization phase. C) The absolute refractory period would be shorter than normal. D) The axon would be unable to generate action potentials. E) None, because the chemically gated sodium channels would still function.

The axon would be unable to generate action potentials.

71) If the potassium permeability of a resting neuron increases above the resting permeability, what effect will this have on the transmembrane potential? A) The inside of the membrane will become more positive. B) The inside of the membrane will become more negative. C) There will be almost no effect on transmembrane potential. D) The membrane will become depolarized. E) The outside of the membrane will become more positive.

The inside of the membrane will become more negative.

93) Which of the following statements about the action potential is false? A) The rapid depolarization phase is caused by the entry of potassium ions. B) During the repolarization phase, sodium channels close and potassium channels open. C) During the depolarization phase, membrane potential becomes positive. D) In the hyperpolarization phase, membrane potential approaches the potassium equilibrium potential. E) The rapid depolarization phase is caused by the entry of sodium ions.

The rapid depolarization phase is caused by the entry of potassium ions.

81) A shift of the resting transmembrane potential toward 0 mV is called A) depolarization. B) repolarization. C) hyperpolarization. D) non-polarization. E) hypopolarization.

depolarization.

67) Raising the potassium ion concentration in the extracellular fluid surrounding a nerve cell will have which effect? A) depolarize the membrane potential B) hyperpolarize the membrane potential C) increase the magnitude of the potassium equilibrium potential D) repolarize the membrane potential E) increase the magnitude of the sodium equilibrium potential

depolarize the membrane potential

61) The sum of the electrical and chemical forces acting on an ion is known as its ________ gradient. A) osmotic B) chemiosmotic C) concentration D) potential E) electrochemical

electrochemical

102) An action potential traveling along the entire length of an axon demonstrates ________ propagation. A) relative B) saltatory C) continuous D) graded E) degraded

continuous

33) In a(n) ________ neuron, the dendrites and axon are continuous or fused. A) multipolar B) anaxonic C) unipolar D) bipolar E) pseudopolar

33: unipolar

34) ________ neurons are the most common class in the CNS. A) Multipolar B) Anaxonic C) Unipolar D) Bipolar E) Pseudopolar

34: multipolar

65) The equilibrium potential for potassium ions occurs at approximately A) -90 mV. B) -70 mV. C) +66 mV. D) 0 mV. E) -55 mV.

-90mV

103) At a(n) ________ synapse, a neurotransmitter is released to stimulate the postsynaptic membrane. A) electrical B) chemical C) electrochemical D) ionic E) charged

103: chemical

104) In a(n) ________ synapse, current flows directly between cells. A) electrical B) chemical C) electrochemical D) ionic E) charged

104: electrical

105) Which type of synapse is most common in the nervous system? A) chemical B) electrical C) mechanical D) processing E) radiative

105: chemical

15) Which of the following is not contained in the axoplasm of the axon? A) neurotubules B) mitochondria C) vesicles D) neurofibrils E) Nissl bodies

15: nissl bodies

23) ________ monitor the internal environment. A) Endoceptors B) Interoceptors C) Exteroceptors D) Special sensory receptors E) Sensory ganglia

22:interoceptors

28) Neurons that have several dendrites and a single axon are called A) anaxonic. B) unipolar. C) bipolar. D) tripolar. E) multipolar.

28: multipolar

29) Sensory neurons of the PNS are A) anaxonic. B) unipolar. C) bipolar. D) tripolar. E) multipolar.

29; unipolar

63) The Na-K ion exchange pump actively transports A) 1 intracellular sodium ion for 2 extracellular potassium ions. B) 2 intracellular sodium ions for 1 extracellular potassium ion. C) 3 intracellular sodium ions for 1 extracellular potassium ion. D) 3 intracellular sodium ions for 2 extracellular potassium ions. E) 3 extracellular sodium ions for 2 intracellular potassium ions.

3 intracellular sodium ions for 2 extracellular potassium ions.

31) ________ neurons are small and have no anatomical features that distinguish dendrites from axons. A) Multipolar B) Anaxonic C) Unipolar D) Bipolar E) Pseudopolar

31: anaxonic

32) ________ neurons are short, with a cell body between dendrite and axon, and occur in special sense organs. A) Multipolar B) Anaxonic C) Unipolar D) Bipolar E) Pseudopolar

32: bipolar

84) The following are the main steps in the generation of an action potential. 1. Sodium channels are inactivated. 2. Voltage-gated 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

43) Which of the following are not types of neuroglia? A) ependymal cells B) microglia C) astrocytes D) oligodendrocytes E) interneurons

43: interneurons

44) ________ account for roughly half of the volume of the nervous system. A) Axons B) Dendrites C) Neuroglia D) Synapses E) Efferent fibers

44: neuroglia

45) The largest and most numerous neuroglia in the CNS that absorb and recycle neurotransmitters are the A) astrocytes. B) ependymocytes. C) microglia. D) oligodendrocytes. E) tanycytes.

45: astrocytes

46) The smallest neuroglia of the CNS that act as phagocytes are the A) astrocytes. B) ependymocytes. C) microglia. D) oligodendrocytes. E) tanycytes.

46: microglia

52) After a stroke, what type of glial cell accumulates within the affected brain region? A) Schwann cells B) satellite cells C) oligodendrocytes D) microglia E) ependymal cells

52: microglia

54) The neurilemma of axons in the peripheral nervous system is formed by A) astrocytes. B) satellite cells. C) oligodendrocytes. D) microglia. E) Schwann cells.

54: Schwann cells

55) Glial cells that surround the neurons in ganglia are A) astrocytes. B) satellite cells. C) oligodendrocytes. D) microglia. E) ependymal cells.

55: satellite cells

66) Ion channels that are always open are called ________ channels. A) active B) gated C) leak D) regulated E) local

66: leak

95) The period from when an action potential begins until another action potential could be initiated is known as the ________ period. A) depolarization B) absolute refractory C) relative refractory D) repolarization E) hyperpolarization

95: absolute refractory

4) The ________ nervous system provides involuntary regulation of smooth muscle, cardiac muscle, and glandular activity. A) somatic B) autonomic C) sensory division of the peripheral D) automatic E) special sensory

Autonomic

6) The plasma membrane of an axon is called the A) axon hillock. B) axoplasm. C) axolemma. D) axon terminal. E) axokaryon.

Axolemma

9) The axon is connected to the cell body at the A) telodendria. B) synaptic knobs. C) collateral branches. D) axon hillock. E) synapse.

Axon hillock

2) The ________ nervous system is composed of the brain and spinal cord. A) autonomic B) peripheral C) central D) efferent E) afferent

Central

75) ________ channels open or close in response to binding specific molecules. A) Leak B) Activated C) Chemically gated D) Voltage-gated E) Mechanically-gated

Chemically gated

10) Branches that may occur along an axon are called A) dendrites. B) synaptic knobs. C) collateral branches. D) hillocks. E) synapses.

Collateral branches

1) Which of the following is not a function of the nervous system? A) sense the internal and external environments B) integrate sensory information C) coordinate voluntary and involuntary activities D) direct long-term functions, such as growth E) control peripheral effectors

Direct long-term functions, such as growth

62) Which of the following interactions between electrical and chemical gradients does not lead to the establishment of a neuronʹs resting potential? A) Chemical and electrical forces both favor sodium ions entering the cell. B) Electrical forces push sodium ions out of the cell. C) Chemical forces tend to drive potassium ions out of the cell. D) Potassium ions are attracted to the negative charges inside the cell. E) Potassium ions are repulsed by positive charges outside the cell.

Electrical forces push sodium ions out of the cell.

synaptic terminals

Ends of axons that form one side of the synaptic cleft; the location where neurotransmitters are stored.

41) ________ line the brain ventricles and spinal canal. A) Astrocytes B) Satellite cells C) Oligodendrocytes D) Microglia E) Ependymal cells

Ependymal cells

94) How would the absolute refractory period be affected if voltage-regulated sodium channels failed to inactivate? A) It would last indefinitely. B) It would be much briefer. C) It would be basically unaffected.

It would last indefinitely.

76) ________ channels open or close in response to physical distortion of the membrane surface. A) Voltage-gated B) Chemically gated C) Active D) Mechanically gated E) Leak

Mechanically gated

70) Which of the following is not involved in creating the resting potential of a neuron? A) diffusion of potassium ions out of the cell B) diffusion of sodium ions into the cell C) Membrane permeability for sodium ions is greater than for potassium ions. D) Membrane permeability for potassium ions is greater than for sodium ions. E) The interior of the plasma membrane has an excess of negative charges.

Membrane permeability for sodium ions is greater than for potassium ions.

5) The basic functional unit of the nervous system is the A) brain. B) spinal cord. C) nerve. D) glial cell. E) neuron.

Neuron

8) Clusters of RER and free ribosomes in neurons are called A) neurofilaments. B) neurofibrils. C) perikaryon. D) Nissl bodies. E) microglia.

Nissl bodies

14) Which of the following is not associated with the cytoskeleton of the perikaryon? A) neurofilaments B) axon C) dendrite D) nucleus E) neurofibrils

Nucleus

87) Which of the following statement is false when comparing neurons and muscle tissue? A) Muscle tissue and nerves are both excitable. B) Muscle tissue and neurons both have a resting membrane potential. C) Muscle tissue and neurons both have refractory periods. D) Resting membrane potentials are greater (more positive) in muscle compare to neurons. E) Action potentials last longer in muscle tissues compared to neurons.

Resting membrane potentials are greater (more positive) in muscle compare to neurons.

3) The ________ nervous system controls the skeletal muscles. A) sympathetic B) parasympathetic C) afferent D) somatic E) autonomic

Somatic

13) The site of intercellular communication between neurons is the A) telodendria. B) synaptic knob. C) collateral branch. D) hillock. E) synapse.

Synapse

79) Which is not true of voltage-gated sodium channels? A) They have both an activation gate and an inactivation gate that work independent of each other. B) They open and close in response to changes in the membrane potential. C) They are found on excitable membranes. D) They have both an activation gate and an inactivation gate that work dependent of each other. E) None of these is false.

They have both an activation gate and an inactivation gate that work dependent of each other.

12) Neurotransmitter for release is stored in synaptic A) telodendria. B) knobs. C) vesicles. D) mitochondria. E) neurosomes.

Vesicles

98) The period during which an excitable membrane cannot respond to further stimulation is the A) hyperpolarization. B) depolarization. C) relative refractory period. D) repolarization. E) absolute refractory period.

absolute refractory period

107) Cholinergic synapses release the neurotransmitter A) norepinephrine. B) epinephrine. C) serotonin. D) acetylcholine. E) GABA.

acetylcholine

86) The all-or-none principle states that A) all stimuli will produce identical action potentials. B) all stimuli great enough to bring the membrane to threshold will produce identical action potentials. C) the greater the magnitude of the stimuli, the greater the magnitude 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.

97) The ________ principle states that the size and speed of an action potential are independent of the stimulus strength. A) threshold B) all-or-none C) graded potential D) saltatory propagation E) summation

all-or-none

25) Neurons that are rare, small, and lack features that distinguish dendrites from axons are called A) anaxonic. B) unipolar. C) bipolar. D) tripolar. E) multipolar.

anaxonic

38) The glial cells in the central nervous system that form scar tissue after central nervous system injury are the A) astrocytes. B) satellite cells. C) oligodendrocytes. D) microglia. E) ependymal cells.

astrocytes

59) Which part(s) of the neuron can conduct an action potential? A) dendrites B) dendrites and cell body C) cell body and axon D) axon and telodendria E) dendrites and telodendria

axon and telodendria

27) Neurons that have one axon and one dendrite, with the soma in between, are called A) anaxonic. B) unipolar. C) bipolar. D) tripolar. E) multipolar

bipolar

69) If the permeability of sodium ions increases in an axon, A) the membrane potential will depolarize. B) the membrane potential will hyperpolarize. C) inward movement of sodium ions will increase. D) outward movement of sodium ions will decrease. E) both the inward movement of sodium ions will increase and the membrane potential will depolarize.

both the inward movement of sodium ions will increase and the membrane potential will depolarize.

106) The ion that triggers the release of acetylcholine into the synaptic cleft is A) sodium. B) potassium. C) calcium. D) chloride. E) magnesium.

calcium.

39) Functions of astrocytes include all of the following except A) maintaining the blood-brain barrier. B) conducting action potentials. C) absorbing excess neurotransmitter. D) responding to neural tissue damage. E) forming a three-dimensional framework for the CNS.

conducting action potentials.

82) Opening of sodium channels in the axon membrane causes A) hyperpolarization and decreased positive charge inside the membrane. B) repolarization and increased positive charge inside the membrane. C) hyperpolarization and increased negative charge inside the membrane. D) depolarization and increased negative change inside the membrane. E) depolarization and increased positive charge inside the membrane.

depolarization and increased positive charge inside the membrane.

101) In the process of continuous propagation, all of the following are true except A) the action potential is triggered by graded depolarization of the initial segment. B) at threshold, sodium channels begin to open rapidly. C) local currents depolarize the region just adjacent to the active zone. D) depolarization of the axonal membrane only occurs at nodes. E) each step takes about one millisecond.

depolarization of the axonal membrane only occurs at nodes.

78) Ions can move across the plasma membrane in all of the following ways except A) through voltage-gated channels along the axolemma. B) through passive or leak channels. C) by ATP-dependent ion pumps like the sodium-potassium exchange pump. D) through chemically-gated channels as in neuromuscular transmission. E) diffusion directly through the plasma membrane.

diffusion directly through the plasma membrane.

21) ________ provide information about the external environment. A) Proprioceptors B) Interoceptors C) Exteroceptors D) Somatic sensory receptors E) Interneurons

exteroceptors

49) Damage to ependymal cells would most likely affect the A) formation of myelin sheaths. B) formation of cerebrospinal fluid. C) formation of ganglia. D) repair of axons. E) transport of neurotransmitters within axons.

formation of cerebrospinal fluid.

57) In the peripheral nervous system, Schwann cells participate in the repair of damaged nerves by A) producing new axons. B) regenerating cell bodies for the neurons. C) forming a cellular cord that directs axonal regrowth. D) clearing away cellular debris. E) producing more satellite cells that fuse to form new axons.

forming a cellular cord that directs axonal regrowth.

35) Neuron cell bodies in the PNS are clustered together in masses called A) nerves. B) ganglia. C) the spinal cord. D) peripheral nerves. E) nuclei.

ganglia

51) Regions of the CNS where neuron cell bodies dominate constitute the ________ matter. A) white B) grey C) clear D) dark E) yellow

grey

74) Voltage-gated channels are present A) at the motor end plate. B) on the surface of dendrites. C) in the membrane that covers axons. D) on the soma of neurons. E) along the perikaryon of neurons.

in the membrane that covers axons.

73) Opening of each of the following types of channels will contribute toward a graded potential except A) closed voltage-gated sodium channel. B) chemically gated acetylcholine receptor. C) sodium leak channel. D) mechanically gated sodium channel. E) inactivated voltage-gated sodium channel

inactivated voltage-gated sodium channel

36) ________ are the most numerous type of neuron in the CNS. A) Sensory neurons B) Motor neurons C) Unipolar neurons D) Bipolar neurons E) Interneurons

interneurons

20) ________ monitor the digestive, respiratory, cardiovascular, urinary, and reproductive systems. A) Proprioceptors B) Interoceptors C) Exteroceptors D) Somatic sensory receptors E) Special sense receptors

interoceptors

68) If the sodium-potassium pumps in the plasma membrane fail to function, all of the following occur except that the A) intracellular concentration of potassium ions will increase. B) neuron will slowly depolarize. C) membrane will slowly lose its capacity to generate action potentials. D) inside of the membrane will have a resting potential that is more positive than normal. E) intracellular concentration of sodium ions will increase.

intracellular concentration of potassium ions will increase.

64) The resting membrane potential exists mainly due to passive ________ channels. A) leak B) active C) chemically gated D) voltage-gated E) mechanically-gated

leak

83) Graded potentials A) produce an effect that increases with distance from the point of stimulation. B) produce an effect that spreads actively across the membrane surface without diminishing. C) may be either a depolarization or a hyperpolarization. D) are often all-or-none. E) always cause repolarization.

may be either a depolarization or a hyperpolarization.

37) Which of the following is not a function of the neuroglia? A) support B) memory C) secretion of cerebrospinal fluid D) maintenance of blood-brain barrier E) phagocytosis

memory

42) Small, wandering cells that engulf cell debris and pathogens in the CNS are called A) astrocytes. B) satellite cells. C) oligodendrocytes. D) microglia. E) ependymal cells.

microglia

72) The sodium-potassium ion exchange pump A) is not involved in producing the resting membrane potential. B) transports sodium ions into the cell during depolarization. C) transports potassium ions out of the cell during repolarization. D) moves sodium and potassium opposite to the direction of their electrochemical gradients. E) depends on a hydrogen gradient for energy.

moves sodium and potassium opposite to the direction of their electrochemical gradients.

24) The most abundant class of neuron in the central nervous system is A) anaxonic. B) bipolar. C) multipolar. D) pseudopolar. E) unipolar.

multipolar

58) The tiny gaps between adjacent Schwann cells are called A) gap junctions. B) synapses. C) myelinated. D) nodes. E) internodes.

nodes

40) The myelin sheath that covers many CNS axons is formed by A) astrocytes. B) satellite cells. C) oligodendrocytes. D) microglia. E) ependymal cells.

oligodendrocytes.

60) The separation of plus and negative charges across the membrane creates a ________ difference, or voltage. A) kinetic B) potential C) concentration D) gradient E) graded

potential

22) ________ monitor the position of skeletal muscles and joints. A) Proprioceptors B) Interoceptors C) Exteroceptors D) Somatic sensory receptors E) Special sensory receptors

propriopceptors

19) Which of the following is not a recognized structural classification for neurons? A) anaxonic B) bipolar C) multipolar D) pseudopolar E) unipolar

pseudopolar

48) Extensive damage to oligodendrocytes in the CNS could result in A) loss of the structural framework of the brain. B) a breakdown of the blood-brain barrier. C) inability to produce scar tissue at the site of an injury. D) decreased production of cerebrospinal fluid. E) reduced speed of nerve impulses.

reduced speed of nerve impulses.

99) The period during which an excitable membrane can respond again, but only if the stimulus is greater than the threshold stimulus, is the A) refractory period. B) depolarization. C) relative refractory period. D) repolarization. E) absolute refractory period.

relative refractory period

53) Which of the following is a type of glial cell found in the peripheral nervous system? A) astrocytes B) satellite cells C) oligodendrocytes D) microglia E) ependymal cells

satellite cells

30) Which of the following activities or sensations is not monitored by interoceptors? A) sight B) joint movement C) activities of the digestive system D) cardiovascular activities E) urinary activities

sight

47) Many medications introduced into the bloodstream cannot directly affect the neurons of the CNS because A) oligodendrocytes form a continuous myelin sheath around the axons. B) the astrocytes isolate the CNS by forming a blood-brain barrier. C) the neurilemma is impermeable to most molecules. D) ependymal cells restrict the flow of interstitial fluid between the capillaries and the neurons. E) Schwann cells form a capsule around neurons

the astrocytes isolate the CNS by forming a blood-brain barrier.

96) The minimum stimulus required to trigger an action potential is known as the A) graded potential. B) resting potential. C) threshold. D) refractory period. E) membrane potential.

threshold

26) Neurons in which dendritic and axonal processes are continuous and the soma lies off to one side are called A) anaxonic. B) unipolar. C) bipolar. D) tripolar. E) multipolar.

unipolar

77) A gated channel that responds to changes in transmembrane potential is called a(n) ________ channel. A) leak-gated B) voltage-gated C) chemically gated D) mechanically gated E) ATP

voltage-gated

85) Which type of membrane channels are found in axons? A) voltage-gated Na+ channels B) voltage-gated K+ channels C) chemically gated Na+ and K+ channels D) voltage-gated Ca2+ channels E) voltage-gated Na+ and K+ channels

voltage-gated Na+ and K+ channels

56) Deteriorating changes in the distal segment of an axon as a result of a break between it and the soma is called ________ degeneration. A) neural B) central C) peripheral D) Wallerian E) conduction

wallerian

100) Which of the following does not influence the time necessary for a nerve impulse to be transmitted? A) length of the axon B) presence or absence of a myelin sheath C) diameter of the axon D) presence or absence of nodes E) whether or not the impulse begins in the CNS

whether or not the impulse begins in the CNS

50) Regions of the CNS with an abundance of myelinated axons constitute the ________ matter. A) white B) grey C) clear D) dark E) yellow

white

16) Most CNS neurons lack centrioles. This observation explains A) why CNS neurons grow such long axons. B) why CNS neurons cannot divide. C) the ability of neurons to generate an action potential. D) the ability of neurons to communicate with each other. E) the ability of neurons to produce a resting potential.

why CNS neurons cannot divide.