Deck 8: Neurons: Cellular and Network Properties

Question 1

Neurotransmitters are released from the

A) dendrites.
B) axon terminals.
C) collaterals.
D) axon hillock.
E) synapse.

Answer 1

B

Question 2

The brain and spinal cord together compose the

A) central nervous system.
B) autonomic division system.
C) somatic motor division of the nervous system.
D) peripheral nervous system.
E) visceral nervous system.

Answer 2

A

Question 3

The afferent and efferent axons together form the

A) central nervous system.
B) autonomic division system.
C) somatic motor division of the nervous system.
D) peripheral nervous system.
E) visceral nervous system.

Answer 3

D

Question 4

The axon is connected to the cell body by the

A) myelin sheath.
B) axon terminal.
C) collaterals.
D) axon hillock.
E) synapse.

Question 5

Anterograde and retrograde axonal transport are forms of ________ transport.

A) fast
B) slow
C) Neither of these

Question 6

The multiple thin,branched structures on a neuron whose main function is to receive incoming signals are the

A) cell bodies.
B) axons.
C) dendrites.
D) somata.
E) None of the answers are correct.

Question 7

The portions of a neuron that extend off of the roughly spherical cell body are usually collectively called

A) protrusions.
B) processes.
C) prostheses.
D) projections.

Question 8

The cell body of neurons is generally

A) 90% of the cell volume.
B) 50% of the cell volume.
C) 10% of the cell volume.
D) found in the same position on every neuron.

Question 9

The region where the axon terminal meets its target cell is called the

A) collateral.
B) hillock.
C) synapse.
D) nerve.
E) dendrites.

Question 10

Exocrine glands,smooth muscles,and cardiac muscles are controlled by the

A) central nervous system.
B) autonomic nervous system.
C) somatic motor division.
D) peripheral nervous system.
E) enteric nervous system.

Question 11

The enteric nervous system is a network of neurons that function in controlling

A) reproduction.
B) digestion.
C) excretion, particularly urination.
D) the skeletal system.
E) the endocrine system.

Question 12

Information coming into the central nervous system is transmitted along ________ neurons.

A) afferent
B) sensory
C) efferent
D) afferent and sensory
E) sensory and efferent

Question 13

Detailed understanding of the cellular basis of signaling in the nervous system has led to good understanding of consciousness,intelligence,and emotion.

Question 14

Autonomic motor neurons are subdivided into the

A) visceral and somatic divisions.
B) sympathetic and parasympathetic divisions.
C) central and peripheral divisions.
D) visceral and enteric divisions.
E) somatic and enteric divisions.

Question 15

In general,the nervous system is composed of which two types of cells?
1)motor
2)neurons
3)sensory
4)glial
5)associative

A) 1 and 2
B) 1 and 3
C) 2 and 4
D) 3 and 4
E) 3 and 5

Question 16

Interneurons are found

A) only in the brain.
B) only in the spinal cord.
C) only in the CNS.
D) throughout the nervous system.
E) only in spinal nerves.

Question 17

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

A) dendrites.
B) axon terminals.
C) collaterals.
D) axon hillocks.
E) synapses.

Question 18

The collection of axons that carries information between the central nervous system and the peripheral effectors is called the

A) axon hillock.
B) varicosity.
C) axon.
D) dendrite.
E) nerve.

Question 19

The term axonal transport refers to

A) the release of neurotransmitter molecules from the axon.
B) the transport of microtubules to the axon for structural support.
C) vesicle transport of proteins and organelles down the axon.
D) the movement of the axon terminal to synapse with a new postsynaptic cell.
E) None of the answers are correct.

Question 20

Neurotransmitter is stored and released from

A) axon terminals only.
B) axon varicosities only.
C) dendritic spines only.
D) cell bodies only.
E) axon terminals and axon varicosities.

Question 21

Glial cells

A) only provide structural and metabolic support.
B) only guide neurons during growth and repair.
C) only help maintain homeostasis of the brain's extracellular fluid.
D) provide structural and metabolic support and help maintain homeostasis of the brain's extracellular fluid.
E) All of the answers are correct.

Question 22

The total amount of neurotransmitter released at the axon terminal is directly related to

A) the amplitude of the action potential.
B) the length of the axon.
C) the total number of action potentials.
D) the amplitude of the graded potential.

Question 23

Which of the following is the most common location where action potentials originate?

A) dendrites
B) cell body
C) axon hillock
D) synaptic cleft
E) synaptic bouton

Question 24

Glial cells communicate primarily using

A) electrical signals only.
B) chemical signals only.
C) neurotransmitters only.
D) neuromodulators only.
E) electrical signals and chemical signals.

Question 25

Choose all of the items that are incorrectly matched.

A) inactivation gate - closed at rest
B) activation gate - open at rest
C) inactivation gate - closed during repolarization
D) activation gate - opens during depolarization
E) All of the answers are incorrectly matched.

Question 26

Myelin is formed by

A) axons only.
B) Schwann cells only.
C) oligodendrocytes only.
D) Schwann cells and oligodendrocytes.

Question 27

The Nernst equation predicts

A) intracellular ion concentrations.
B) extracellular ion concentrations
C) the membrane potential resulting from all permeable ions.
D) the membrane potential resulting from permeability to a single ion.
E) the threshold membrane potential.

Question 28

Clusters of nerve cell bodies in the peripheral nervous system are called

A) microglia.
B) neuroglia.
C) glia.
D) ganglia.
E) nodes.

Question 29

The falling phase of the action potential is due primarily to

A) Na⁺ flow in the cell only.
B) Na⁺ flow out of the cell only.
C) K⁺ flow out of the cell only.
D) K⁺ flow into the cell only.
E) Na⁺ flow out of the cell and K⁺ flow into the cell.

Question 30

Which ion(s)is/are higher in concentration inside the cell compared to outside?

A) potassium
B) sodium
C) chloride
D) calcium
E) More than one of the answers is correct.

Question 31

These glial cells may contribute to Lou Gehrig's disease.

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

Question 32

The resting membrane potential results from

A) uneven distribution of ions across the cell membrane only.
B) differences in membrane permeability to Na⁺ and K⁺ only.
C) activity of the sodium/potassium pump only.
D) uneven distribution of ions across the cell membrane and differences in membrane permeability to Na⁺ and K⁺.
E) None of the answers are correct.

Question 33

The point during an action potential when the inside of the cell has become more positive than the outside is known as the

A) depolarization.
B) rising phase.
C) falling phase.
D) overshoot.
E) peak.

Question 34

The channelopathy known as QT syndrome is a result of mutation in ________ channels.

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

Question 35

These glial cells act as scavengers.

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

Question 36

Ion channel inactivation is

A) closing of the channel in response to decrease in the stimulus.
B) closing of the channel even when the stimulus continues.
C) any type of channel closing.
D) None of the answers are correct.

Question 37

Which is the correctly written Nernst equation?

A) 61/z × log [ion]_out / [ion]_in
B) 61/z × log [ion]_in / [ion]_out
C) log 61/z × [ion]_in / [ion]_out
D) log 61/z × [ion]_out / [ion]_in

Question 38

The absolute refractory period of an action potential

A) only ensures one-way travel down an axon.
B) only allows a neuron to ignore a second signal sent that closely follows the first.
C) only prevents summation of action potentials.
D) ensures one-way travel down an axon and allows a neuron to ignore a second signal sent that closely follows the first.
E) ensures one-way travel down an axon, allows a neuron to ignore a second signal sent that closely follows the first, and prevents summation of action potentials.

Question 39

The rising phase of the action potential is due to

A) Na⁺ flow into the cell only.
B) Na⁺ flow out of the cell only.
C) K⁺ flow out of the cell only.
D) K⁺ flow into the cell only.
E) Na⁺ flow out of the cell and K⁺ flow into the cell.

Question 40

What does the Goldman-Hodgkin-Katz equation take into account that the Nernst equation does NOT?

A) the electrical charges of the ions
B) the permeabilities of the ions
C) the solubilities of the ions
D) the sizes of the ions
E) the temperature

Question 41

The sodium-potassium exchange pump

A) must re-establish ion concentrations after each action 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 in the direction of their chemical gradients.
E) requires ATP to function.

Question 42

Voltage-regulated channels are located

A) within the cytosol only.
B) in the membranes of dendrites only.
C) in the membranes of axons only.
D) on the neuron cell body only.
E) in the membranes of dendrites, in the membranes of axons, and on the neuron cell body.

Question 43

A chemical synapse ALWAYS includes ________.
1)axon terminal
2)presynaptic cell
3)synaptic cleft
4)postsynaptic cell
5)dendrite

A) 1, 2, 3, 4, 5
B) 1, 2, 3, 4
C) 2, 3, 4
D) 2, 3, 4, 5
E) 1, 3, 4

Question 44

Which of the following will best increase the conduction rate of action potentials?

A) Increase the diameter of the axon, decrease the resistance of the axon membrane to ion leakage.
B) Increase the diameter of the axon, increase the resistance of the axon membrane to ion leakage.
C) Decrease the diameter of the axon, decrease the resistance of the axon membrane to ion leakage.
D) Decrease the diameter of the axon, increase the resistance of the axon membrane to ion leakage.

Question 45

Action potentials are primarily associated with the membranes of

A) dendrites only.
B) cell bodies only.
C) axons only.
D) dendrites and axons.
E) cell bodies and axons.

Question 46

Which type of synapse is most prevalent in the nervous system?

A) chemical
B) electrical
C) mechanical
D) processing
E) radiative

Question 47

Graded potentials may

A) initiate an action potential.
B) depolarize the membrane to the threshold voltage.
C) hyperpolarize the membrane.
D) be called EPSPs or IPSPs.
E) All of the statements are true.

Question 48

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 action potentials of identical magnitude.
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.

Question 49

To increase the amount of neurotransmitter released onto a postsynaptic cell,the presynaptic cell would have to

A) send action potentials with higher voltage (higher amplitude).
B) send action potentials with longer durations.
C) send action potentials with higher frequency.
D) do nothing; no change is possible since the all-or-none law is in effect.

Question 50

Some neurotoxins work essentially the same way as some local anesthetics,which is to

A) inactivate the enzyme that destroys the neurotransmitter only.
B) bind to Na⁺ channels and inactivate them only.
C) prevent depolarization by blocking Na⁺ entry into the cell only.
D) inactivate the enzyme that destroys the neurotransmitter and bind to Na⁺ channels and inactivate them.
E) bind to Na⁺ channels and inactivate them and prevent depolarization by blocking Na⁺ entry into the cell.

Question 51

In the membrane of a resting nerve cell,when chemically gated Cl^- channels open,

A) Cl^- ions enter the cell.
B) Cl^- ions leave the cell.
C) the cell becomes depolarized.
D) Cl^- ions enter the cell and the cell becomes depolarized.
E) Cl^- ions leave the cell and the cell becomes depolarized.

Question 52

Which of the following does NOT influence the time necessary for a nerve impulse to be conveyed by a particular neuron?

A) length of the axon
B) presence or absence of a myelin sheath
C) diameter of the axon
D) presence or absence of nodes of Ranvier
E) whether axon is sensory or motor

Question 53

The ion necessary to initiate the release of acetylcholine into the synaptic cleft is

A) sodium.
B) potassium.
C) calcium.
D) chloride.
E) zinc.

Question 54

Ion concentrations are first significantly affected after ________ action potential(s).

A) one
B) a few dozen
C) a few hundred
D) a few thousand
E) a few million

Question 55

All of the following must occur before a second action potential can begin,EXCEPT

A) the Na⁺ and K⁺ ions that moved in/out of the cell must move back to their original compartments.
B) the Na⁺ inactivation gate must open and the Na⁺ activation gate must close.
C) the absolute refractory period must occur.
D) the Na⁺ and K⁺ ions that moved in/out of the cell must move back to their original compartments; the Na⁺ inactivation gate must open; and the Na⁺ activation gate must close.
E) None of the answers are correct.

Question 56

When voltage-gated Na⁺ channels of a resting neuron open,

A) Na⁺ enters the neuron.
B) Na⁺ leaves the neuron.
C) the neuron depolarizes.
D) Na⁺ enters the neuron and the neuron depolarizes.
E) Na⁺ leaves the neuron and the neuron depolarizes.

Question 57

The term hyperkalemia specifically indicates too much potassium in which fluid compartment?

A) blood
B) intracellular
C) interstitial
D) extracellular
E) All of the answers are correct.

Question 58

When voltage-gated K⁺ channels of a resting neuron open,

A) K⁺ enters the neuron.
B) K⁺ leaves the neuron.
C) the neuron depolarizes.
D) K⁺ enters the neuron and the neuron depolarizes.
E) K⁺ leaves the neuron and the neuron depolarizes.

Question 59

In order to signal a stronger stimulus,action potentials become

A) higher in amplitude only.
B) more frequent only.
C) longer-lasting only.
D) higher in amplitude and more frequent.
E) higher in amplitude and longer-lasting.

Question 60

The major determinant of the resting potential of all cells is

A) Ca²⁺ concentration in the blood and interstitial fluid.
B) Na⁺ concentration in the blood and interstitial fluid.
C) K⁺ gradient between the blood and interstitial fluid.
D) K⁺ concentration inside cells.
E) Na⁺ concentration inside cells.

Question 61

The site of information integration in the nervous system is the

A) chemical synapse.
B) electrical synapse.
C) trigger zone.
D) dendritic membrane.
E) axon terminal.

Question 62

In response to binding a neurotransmitter,a postsynaptic cell can

A) only open chemically gated ion channels, causing graded potentials known as fast synaptic potentials.
B) only close ion channels via G proteins and second messenger systems, producing slow responses.
C) only regulate protein synthesis and affect the metabolic activities of the postsynaptic cell.
D) open chemically gated ion channels, causing graded potentials known as fast synaptic potentials and regulate protein synthesis and affect the metabolic activities of the postsynaptic cell.
E) open chemically gated ion channels, causing graded potentials known as fast synaptic potentials, close ion channels via G proteins and second messenger systems, producing slow responses, and regulate protein synthesis and affect the metabolic activities of the postsynaptic cell.

Question 63

When a second EPSP arrives at a single synapse before the effects of the first have disappeared,what occurs?

A) spatial summation
B) temporal summation
C) inhibition of the impulse
D) hyperpolarization
E) decrease in speed of impulse transmission

Question 64

Presynaptic facilitation makes a pathway

A) less likely to be in use, just through hyperpolarization of selected neurons.
B) more likely to be in use, just through depolarization of selected neurons.
C) capable of alteration, just through training and conditioning.
D) less likely to be in use, just through hyperpolarization of selected neurons and capable of alteration, just through training and conditioning.
E) more likely to be in use, just through depolarization of selected neurons and capable of alteration, just through training and conditioning.

Question 65

Excitatory neurotransmitters of the CNS usually act by opening ________ channels.

A) Na⁺
B) K⁺
C) Cl^-
D) H⁺
E) Ca²⁺

Question 66

Which is/are the most common inhibitory neurotransmitter(s)of the CNS?

A) GABA only
B) glycine only
C) glutamate only
D) GABA and glycine
E) All of the answers are correct.

Question 67

The neurotransmitter thought to be involved in learning and memory is

A) norepinephrine.
B) glutamate.
C) acetylcholine.
D) GABA.
E) glycine.

Question 68

If a hyperpolarizing graded potential and a depolarizing graded potential of similar magnitudes arrive at the trigger zone at the same time,what is most likely to occur?

A) An action potential is fired off more quickly than usual.
B) Nothing. They will cancel each other out.
C) The cell becomes hyperpolarized.
D) The cell becomes easier to excite.
E) The cell dies.

Question 69

When two or more graded potentials arrive at the trigger zone,which of the following could happen?

A) An excitatory and inhibitory signal can cancel each other out.
B) Two excitatory stimuli may be additive, and summation could occur.
C) Two inhibitory stimuli may be additive, resulting in lower excitability.
D) An excitatory and inhibitory signal can cancel each other out and two excitatory stimuli may be additive, and summation could occur.
E) An excitatory and inhibitory signal can cancel each other out; two excitatory stimuli may be additive, and summation could occur; and two inhibitory stimuli may be additive, resulting in lower excitability.

Question 70

Identify the FALSE statement.

A) EPSPs that reach threshold can initiate an action potential.
B) The trigger zone is the integrating center of the neuron.
C) IPSPs depolarize the membrane.
D) All of the statements are true.

Question 71

Inhibitory postsynaptic potentials (IPSPs )

A) result in local depolarizations.
B) result in local hyperpolarizations.
C) increase membrane permeability to sodium ions.
D) prevent the escape of potassium ions.
E) prevent the escape of calcium ions.

Question 72

Once the action potential reaches the axon terminal,what happens next?

A) exocytosis of a neurocrine
B) release of the neurotransmitter into the synaptic cleft
C) release of a neurohormone into the blood
D) Any of the above could happen next.

Question 73

Spatial summation refers to

A) electrical signals reaching neurons from outer space.
B) multiple graded potentials arriving at one location simultaneously.
C) repeated graded potentials reaching the trigger zone one after the other.
D) suprathreshold potentials triggering action potentials that are extra large.
E) All of the answers are correct.

Question 74

Once the stimulus alters the receptor on the cell's membrane,what happens next?

A) Ion channels open, allowing ions to enter or exit.
B) The membrane permeability is altered.
C) A second messenger is activated on the inside of the cell.
D) Any of these actions could happen next.

Question 75

In order for a synapse to be an effective means of cellular communication,slow removal or inactivation of neurotransmitter molecules from the synapse is important.

Question 76

Calcium is important in the synapse because it

A) is necessary for acetylcholine synthesis.
B) signals the exocytosis of the neurotransmitter.
C) binds to receptors on the postsynaptic cell, opening ion channels, and triggering graded potentials.
D) leaves the axon terminal, hyperpolarizing the cell.

Question 77

An excitatory postsynaptic potential (EPSP)

A) depolarizes a neuron, decreasing the likelihood of an action potential.
B) hyperpolarizes a neuron, decreasing the likelihood of an action potential.
C) depolarizes a neuron, increasing the likelihood of an action potential.
D) hyperpolarizes a neuron, increasing the likelihood of an action potential.

Question 78

Which of the following is NOT a known drug effect on synaptic function?

A) interfere with neurotransmitter synthesis
B) alter the rate of neurotransmitter release
C) prevent neurotransmitter inactivation
D) prevent neurotransmitter binding to receptors
E) change the type of neurotransmitter found in the synaptic vesicle

Question 79

When multiple,possibly even conflicting signals reach a neuron,the neuron evaluates the signals and may respond or not.This property is called

A) temporal summation.
B) spatial summation.
C) postsynaptic integration.
D) graded potentials.
E) EPSPs.

Question 80

The inhibitory neurotransmitters of the CNS,GABA and glycine,act by opening ________ channels.

A) only Na⁺
B) only Cl^-
C) only K⁺
D) only Ca²⁺
E) Na⁺ and K⁺