Lecture 4: Organization and Cells of the Nervous System

During the transmission of an action potential along the neurilemma of a myelinated neuron, as one node is repolarizing, the next node is depolarizing. A) True B) False

A) True

Myelinated axons transmit action potentials more rapidly than unmyelinated axons. A) True B) False

A) True

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

A) True

The blood-brain barrier may prevent medications from reaching brain tissue. A) True B) False

A) True

The inflow of sodium ions into the intracellular fluid causes depolarization of the neuron's inner cell membrane. A) True B) False

A) True

The nerve impulse is an electrical current that travels along dendrites or axons. A) True B False

A) True

The sodium-potassium pump is involved in establishing the resting membrane potential. A) True B) False

A) True

Threshold is the minimum current required for the cell membrane to generate an action potential. A) True B) False

A) True

Muscarinic ACh receptors act through ____________ activation of K+ channels. A) G-protein B) M-protein C) cGMP D) ATP

A) G-protein

An inhibitory postsynaptic potential would be produced by a neurotransmitter opening Cl- channels. A) True B) False

A) True

Which division of the nervous system innervates involuntary effectors? A) autonomic nervous system B) central nervous system C) somatic nervous system D) associative nervous system

A) autonomic nervous system

Excitotoxicity is caused by A) excessive synaptic release of glutamate. B) GABA inhibition. C) insufficient synaptic release of glutamate. D) insufficient synaptic release of ACh.

A) excessive synaptic release of glutamate.

Where is glycine released? A) in the CNS B) in the PNS C) at the diaphragm D) at skeletal muscleds

A) in the CNS

Which of the following is NOT a structural classification of neurons? A) motor neuron B) bipolar neuron C) multipolar neuron D) pseudounipolar neuron

A) motor neuron

The membrane of resting nerve cells is more permeable to ____________ ions than ____________ ions. A) potassium, sodium B) sodium, potassium C) calcium, potassium D) chloride, potassium

A) potassium, sodium

The average resting membrane potential of an axon is A) -85mV. B) -70mV. C) 0 mV D) +30mV.

B) -70mV.

Action potentials can travel in both directions on the axon. A) True B) False

B) False

Axons require ATP to produce an action potential. A) True B) False

B) False

Both neurons and neuroglia will easily divide by mitosis. A) True B) False

B) False

Cocaine blocks the release of dopamine, norepinephrine, and serotonin. A) True B) False

B) False

Nerve cells depolarize due to the influx of K+. A) True B) False

B) False

Nicotinic receptors utilize G-proteins to regulate the opening of ion channels. A) True B) False

B) False

Which gas(es) can function as a neurotransmitter? A) carbon monoxide B) nitric oxide and carbon monoxide. C) nitric oxide D) carbon dioxide

B) nitric oxide and carbon monoxide.

The period of time when Na+ channels are recovering from their inactive state and K+ channels are still open is the A) relative refractory period. B) Repolarization and relative refractory period are correct. C) repolarization. D) absolute refractory period.

B) Repolarization and relative refractory period are correct.

Absolute refractory period causes... A) action potential propagation to increase B) action potential propagation to occur in one direction C) action potential propagation to occur in both directions D) action potential propagation to cease E) action potential propagation to begin

B) action potential propagation to occur in one direction

Neurotransmitter release would be inhibited by A) blocking repolarization of the axon terminal. B) blocking Ca2+ influx in the axon terminal. C) stimulating protein kinase activity. D) stimulating repolarization of the axon terminal.

B) blocking Ca2+ influx in the axon terminal.

An action potential _____. A) causes the inside of the neuron cell membrane to become neutrally charged in reference to the outside. B) causes the inside of the neuron cell membrane to become positively charged in reference to the outside. C) causes the outside of the neuron cell membrane to become positively charged in reference to the inside. D) causes the inside of the neuron cell membrane to become negatively charged in reference to the outside. E) causes the neuron cell membrane to become unable to alter its charge.

B) causes the inside of the neuron cell membrane to become positively charged in reference to the outside.

Excitatory postsynaptic potentials are produced by A) gamma-aminobutyric acid. B) glutamic acid. C) glycine. D) benzodiazepines.

B) glutamic acid

Depolarization occurs because A) more K+ diffuse out of the cell than Na+ diffuse into it B) more Na+ diffuse into the cell than K+ diffuse out of it C) both Na+ and K+ diffuse into the cell D) more K+ diffuse into the cell than Na+ diffuse out of E) more Na+ diffuse out of the cell than K+ diffuse into it

B) more Na+ diffuse into the cell than K+ diffuse out of it

Which of the following is NOT a type of glutamate receptor? A) NMDA receptor B) muscarinic receptor C) kainate receptor D) All of the choices are correct.

B) muscarinic receptor

Endocannabinoids are retrograde neurotransmitters, meaning they are A) released from presynaptic neurons and diffuse to the postsynaptic neuron. B) released from postsynaptic neurons and diffuse to the presynaptic neuron. C) released from presynaptic neurons and diffuse back to the presynaptic cell body. D) None apply.

B) released from postsynaptic neurons and diffuse to the presynaptic neuron.

Opening of sodium channels and sodium influx causes _____. A) repolarization of the neurons inner cell membrane. B) sodium ions diffusing through the intracellular fluid of the internode to the next node. C) the neuron's outer cell membrane returning to resting membrane potential. D) the EPSP causing the next node to become more positive. E) the neuron's inner cell membrane returning to resting membrane potential.

B) sodium ions diffusing through the intracellular fluid of the internode to the next node.

Nitric oxide A) is a chemical messenger activating adenylate cyclase. B) stimulates the dilation of blood vessels. C) is produced from L-asparagine. D) All apply.

B) stimulates the dilation of blood vessels.

Which of the following statements about the resting membrane potential is TRUE? A) the exterior of the cell has a net negative charge and the interior is neutral B) the exterior of the cell has a net positive charge and the interior has a net negative charge C) the exterior of the cell has a net positive charge and the interior is neutral D) the exterior of the cell is neutral and the interior has a net negative charge E) the exterior of the cell has a net negative charge and the interior has a net positive charge

B) the exterior of the cell has a net positive charge and the interior has a net negative charge

The minimum depolarization needed to open Na+ gates is called the A) repolarization. B) threshold. C) refractory period. D) All-or-none law.

B) threshold

What is NOT true of the relative refractory period? A) K+ is moving out of the axon through its open channels B) a strong stimulus could cause a depolarization C) Na+ channels are inactivated D) many Na+ channels are returning to a closed state

C) Na+ channels are inactivated

Upon arriving at the node of a myelinated neuron, the excitatory postsynaptic potential (EPSP) ____. A) causes the neurons inner cell membrane potential to peak. B) causes the neurons outer cell membrane to become more positively charged. C) causes the neurons inner cell membrane to become more positively charged. D) causes sodium channels to open and sodium to flow into the neuron. E) causes potassium channels to open and potassium to flow out of the neuron.

C) causes the neurons inner cell membrane to become more positively charged.

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

C) myelinated axons in the CNS.

Fetal neuron growth requires the actions of a group of chemicals known as A) glutamates. B) endorphins. C) neurotrophins. D) synapsins.

C) neurotrophins.

Addictive drugs, as well as nicotine, activate dopamine release in the A) basal nuclei. B) corpus callosum. C) nucleus accumbens. D) corpus striatum.

C) nucleus accumbens.

What type of cells produce the myelin sheath in the central nervous system (CNS)? A) astrocytes B) microglia C) oligodendrocytes D) Schwann cells

C) oligodendrocytes

Which ion's movements is responsible for repolarization? A) outward diffusion of Na+ B) influx of K+ C) outward diffusion of K+ D) influx of Na+

C) outward diffusion of K+

Depolarization of the postsynaptic membreane by an excitatory postsynaptic potential (EPSP) causes ____. A) the potassium channels open and potassium ions pour into the extracellular fluid. B) sodium ions diffuse through the neuron's intracellular fluid of the internode. C) the sodium channels open and sodium ions pour into the intracellular fluid. D) repolarization of the neurons inner cell membrane occurs. E) the neurons inner cell membrane potential increases.

C) the sodium channels open and sodium ions pour into the intracellular fluid.

What amino acid are dopamine, norepinephrine, and epinephrine derived from? A) tryptophan B) histidine C) tyrosine D) serine

C) tyrosine

What is present at the axon hillock that allows the production of action potentials? A) ligand-gated channels B) chemical-gated channels C) voltage-gated channels D) muscarinic receptors

C) voltage-gated channels

During depolarization, which of the following statements about voltage-gated ion channels is TRUE? A) K+ gates open before Na+ gates B) Na+ and K+ gates open at the same time C) Na+ gates open while K+ gates remain closed D) Na+ gates open before K+ gates E) K+ gates open while Na+ gates remain closed

D) Na+ gates open before K+ gates

Cholinergic fibers use ____ as the neurotransmitter. A) norepinephrine B) serotonin C) dopamine D) acetylcholine

D) acetylcholine

Enhancing the excitability of a synapse so that transmission is favored along certain pathways is called A) excitotoxicity. B) synaptic plasticity. C) summation. D) long-term potentiation.

D) long-term potentiation.

An action potential generates local currents that tend to _____ the membrane immediately adjacent to the action potential. A) neutralize B) stabilize C) hyperpolarize D) repolarize E) depolarize

E) depolarize