Quiz 11: Introduction to the Nervous System Nervous Tissue

What is NOT a function of the nervous system? A) integrate sensory information B) sense the internal and external environments C) control effectors D) direct long ^-term functions such as growth

Which of the following are organs of the central nervous system? A) brain and cranial nerves B) brain and spinal cord C) spinal cord and spinal nerves D) brain, cranial nerves, spinal cord, and spinal nerves

The two anatomical divisions of the nervous system are the: A) central nervous system and peripheral nervous system. B) sensory division and motor division. C) somatic sensory division and visceral sensory system. D) visceral motor division and somatic motor division.

Upon entering your house, you noticed the smell of cake baking in the oven. What division of the peripheral nervous system is responsible? A) visceral motor division B) somatic motor division C) visceral sensory division D) somatic sensory division

Which nervous system division is responsible for the integration of sensory information? A) visceral motor division B) somatic motor division C) central nervous system D) peripheral nervous system

Which of the following is controlled by the somatic motor division? A) smooth muscle B) cardiac muscle C) skeletal muscle D) glands

Sarah sensed a mosquito land on her arm and swatted it away with her hand. Which specific PNS division was responsible for the movement of Sarah's hand? A) autonomic nervous system B) somatic sensory division C) somatic motor division D) visceral sensory division

The autonomic nervous system does NOT carry signals to: A) cardiac muscle. B) smooth muscle. C) skeletal muscle. D) glands.

Which of the following is NOT a function of neurons? A) integration B) forming the myelin sheath C) transmitting motor information D) carrying sensory information

Determine the direction in which an electrical signal is carried in a typical multipolar neuron. A) axon, cell body, dendrites B) cell body, axon, dendrites C) dendrites, cell body, axon D) dendrites, axon, cell body

Branches that may occur along an axon are called: A) dendrites. B) collaterals. C) hillocks. D) telodendria.

What is the most metabolically active part of a neuron? A) axon hillock B) axon C) dendrites D) cell body

What specific part of the neuron communicates with a target cell and serves as the secretory region of the cell? A) axon terminals (synaptic knobs) B) myelin sheath C) cell body D) dendrites

The conducting region of the neuron is the: A) dendrites. B) axon terminals (synaptic knobs). C) cell body. D) axon.

The most common type of neuron in the human body is: A) unipolar. B) pseudounipolar. C) bipolar. D) multipolar.

Which of the following best describes a bipolar neuron? A) one axon and multiple, highly branched dendrites B) one axon that splits into two processes C) multiple axons and one dendrite D) one axon and one dendrite

What type of neuron is found within the CNS to perform the job of information processing? A) interneurons (association neurons) B) motor (efferent) neurons C) bipolar neurons D) sensory (afferent) neurons

Bundles of axons known as tracts are part of the: A) myelin sheath. B) ganglion. C) peripheral nervous system. D) central nervous system.

Which neuroglial cell helps form the blood ^-brain barrier? A) satellite cell B) oligodendrocyte C) astrocyte D) ependymal cell

Because of their ability to rapidly divide during brain injury, which type of neuroglial cell would be more likely to form a brain tumor? A) oligodendrite B) ependymal cell C) astrocyte D) Schwann cell

Ependymal cells: A) serve as wandering phagocytes during brain injury. B) circulate cerebrospinal fluid. C) help form the blood ^-brain barrier. D) form myelin in the brain and spinal cord.

Which of the following is an effect of myelination? A) Myelination increases the speed of conduction of action potentials. B) Myelination increases the rate of mitosis in damaged neurons. C) Myelination increases the rate at which phagocytosis occurs in the brain. D) Myelination increases the volume of cerebrospinal fluid in circulation.

Myelinated axons in the CNS are known as: A) white matter. B) dark matter. C) internodes. D) gray matter.

Within the PNS, a neuron will regenerate only if: A) the surrounding neuroglia regenerate first. B) the neuron was myelinated. C) the cell body remains intact. D) scar tissue is removed by phagocytosis.

Which of the following is the primary factor in the maintenance of a negative charge during resting membrane potential? A) sodium ^-potassium pump B) ligand ^-gated channels C) leak channels D) voltage ^-gated channels

Resting membrane potential is maintained by the Na⁺/K⁺ pump which brings: A) three potassium ions into the cytosol and three sodium ions into the extracellular fluid. B) three potassium ions into the cytosol and two sodium ions into the extracellular fluid. C) two potassium ions into the cytosol and two sodium ions into the extracellular fluid. D) two potassium ions into the cytosol and three sodium ions into the extracellular fluid.

What channels open or close in response to physical distortion of the membrane surface, such as vibrations or pressure? A) mechanically ^-gated B) chemically ^-gated C) ligand ^-gated D) voltage ^-gated

What type of ion channels is always open? A) active B) local C) leak D) regulated

If a resting axon increases its permeability to sodium ions: A) the outward movement of sodium ions will decrease. B) the membrane potential will hyperpolarize. C) the membrane potential will repolarize. D) the influx of sodium ions will increase and the membrane will depolarize.

The influx of positive charges makes the membrane potential more positive and is known as: A) polarization. B) hyperpolarization. C) depolarization. D) repolarization.

A series of measurements with a voltmeter show a neuron's membrane potential becoming more negative, from ^-70 mV to ^-85 mV. This neuron is experiencing a: A) polarization phase. B) depolarization phase. C) repolarization phase. D) hyperpolarization phase.

Graded potentials: A) cause repolarization. B) produce an effect that spreads actively across the membrane surface. C) produce an effect that increases with distance from the point of stimulation. D) may cause either a depolarization or a hyperpolarization.

Using the information provided in this graph, which statement best summarizes the activity in this neuron? A) The cell gains chloride ions, making the cell hyperpolarize. B) Positive charges are lost from the cell, making the inside more negative. C) The cells gains negative charges, making the inside more negative. D) The cell gains positive charges, making the inside less negative.

What is more likely to promote an action potential? A) repolarization B) absolute refractory period C) hyperpolarization D) depolarization

Which statement best describes the all ^-or ^-none principle? A) All neurons conduct an action potential together, or none do. B) All voltage ^-gated sodium channels will open or none will open. C) An action potential happens completely, or it doesn't happen at all. D) Local, or graded, potentials will always become action potentials.

What membrane potential must generally be met in order to achieve threshold? A) ^-55 mV B) ^-30 mV C) ^-85 mV D) ^-70 mV

Which of the following is correct about threshold? A) Threshold is more positive than the resting potential. B) The membrane begins to hyperpolarize. C) Voltage ^-gated potassium channels inactivate. D) Voltage ^-gated potassium channels begin to close.

During repolarization of a neuron: A) potassium ions move into the cell. B) sodium ions move out of the cell. C) potassium ions move out of the cell. D) sodium ions move into the cell.

Voltage ^-gated sodium channels have both an activation gate and: A) a leak gate. B) a swinging gate. C) a threshold gate. D) an inactivation gate.

Place these steps of the action potential in the correct order. 1. Sodium ions channels return to the resting state and repolarization continues. 2) Voltage ^-gated sodium ion channels activate, sodium ions enter, and the axon section depolarizes. 3) As potassium ion channels return to resting state, the axolemma may hyperpolarize before returning to the resting membrane potential. 4) A local potential depolarizes the axolemma of the trigger zone to threshold. 5) Sodium ion channels inactivate, and voltage ^-gated potassium ion channels activate, so sodium ions stop entering and potassium ions leave, beginning repolarization. A) 2, 4, 5, 1, 3 B) 4, 2, 5, 1, 3 C) 4, 2, 3, 5, 1 D) 4, 2, 1, 3, 5

Which number on the graph represents when voltage ^-gated sodium channels are open? A) 1 B) 2 C) 3 D) 4

Which area on the graph shows when the neuron is in the refractory period? A) 1 B) 2 C) 3 D) 4

Determine the membrane potential (mV) during the relative refractory period. A) ⁺30 mV B) ^-85 mV C) ^-55 mV D) ⁺15 mV

Voltage ^-gated sodium channels are activated: A) during repolarization. B) only if the cell is depolarized to threshold. C) during hyperpolarization. D) after voltage ^-gated potassium channels are activated.

When is the generation of an action potential impossible, no matter the strength of the stimulus? A) absolute refractory period B) relative refractory period C) depolarization D) threshold

During saltatory conduction, action potentials are generated: A) only at nodes of Ranvier of myelinated axons. B) when the entire axolemma is depolarized. C) along the entire length of the unmyelinated axon. D) regardless if threshold is reached.

Determine the fiber type in which propagation of an action potential will occur most quickly. A) myelinated type B fiber B) type C fiber C) myelinated type A fiber D) unmyelinated type B fiber

Which type of fiber has the largest diameter? A) type A B) type B C) type C D) type D

The majority of synapses in the nervous system are: A) electrical. B) mechanical. C) chemical. D) voltage.

The presence of a synaptic cleft between cells is characteristic of: A) chemical synapse. B) electrical synapse. C) both chemical and electrical synapses. D) neither chemical nor electrical synapses.

A neuron that receives neurotransmitters from another neuron is called: A) the postsynaptic neuron. B) an oligodendrocyte. C) the presynaptic neuron. D) a Schwann cell.

What is NOT associated with a chemical synapse? A) presynaptic neuron B) gap junction C) synaptic cleft D) neurotransmitter

What type of synapse must have receptors to transmit signals? A) electrical synapse B) chemical synapse C) both chemical and electrical synapses D) neither chemical nor electrical synapses

What ion triggers synaptic vesicles to release neurotransmitters into the synaptic cleft? A) magnesium B) sodium C) chlorine D) calcium

If the receptor site for a neurotransmitter were completely blocked: A) a weaker action potential would result. B) synaptic transmission would fail. C) neurotransmitter release would stop. D) the presynaptic neuron would release a different neurotransmitter.

Which of the following must happen first in the order events at a chemical synapse? A) Neurotransmitter binds to receptors on the postsynaptic neuron. B) Ion channels respond to the neurotransmitter and lead to a local potential, or possibly an action potential. C) Calcium ion channels in the axon terminal open. D) Calcium ions cause synaptic vesicles to release neurotransmitters into the synaptic cleft.

Which of the following is most likely to produce an action potential? A) opening of potassium ion channels B) hyperpolarization C) inhibitory postsynaptic potential (IPSP) D) excitatory postsynaptic potential (EPSP)

What would most likely lead to an IPSP? A) closure of chloride ion channels B) opening of calcium ion channels C) opening of sodium ion channels D) opening of potassium ion channels

A local hyperpolarization that changes a postsynaptic neuron's membrane from resting potential to ^-85 mV is: A) a saltatory stimulus. B) a temporal stimulus. C) an inhibitory postsynaptic potential (IPSP). D) an excitatory postsynaptic potential (EPSP).

Which of the following would NOT terminate the effects of the neurotransmitter? A) degradation of the neurotransmitter by enzymes B) presence of calcium ions in the presynaptic neuron C) reuptake of neurotransmitter into the presynaptic neuron D) diffusion of the neurotransmitter into the extracellular fluid

When a second EPSP arrives at a single synapse before the effects of the first have disappeared, what results? A) hyperpolarization B) spatial summation C) inhibition of the impulse D) temporal summation

Summation that results from the cumulative effect of multiple synapses at multiple places on the neuron is designated: A) hyperpolarization. B) spatial summation. C) temporal summation. D) impulse transmission.

The same ________ can have different effects depending on the properties of the _. A) receptor; neurotransmitter B) neurotransmitter; receptor C) substrate; enzyme D) hormone; neurotransmitter

Neurotransmitters that bind ionotropic receptors control: A) the activation of G ^-proteins inside the postsynaptic neuron. B) some metabolic process inside the postsynaptic neuron. C) the formation of a second messenger inside the postsynaptic neuron. D) the movement of ions into or out of the postsynaptic neuron.

Cholinergic synapses use the neurotransmitter: A) norepinephrine. B) serotonin. C) acetylcholine. D) epinephrine.

After acetylcholinesterase (AChE) acts, the presynaptic neuron: A) reabsorbs the acetate. B) reabsorbs the choline. C) reabsorbs synaptic vesicles. D) reabsorbs acetylcholine.

Which of the following is the most important excitatory neurotransmitter in the CNS? A) dopamine B) GABA C) glutamate D) glycine

Which neuropeptide neurotransmitter is released from fibers transmitting sensory information about pain and temperature? A) substance P B) opioids C) neuropeptide Y D) endorphin

Where are neuronal pools located? A) within nerves B) within the CNS C) within the PNS D) within ganglia

Neuronal pools are collections of: A) efferent neurons. B) interneurons. C) motor neurons. D) bipolar neurons.

What best describes a converging circuit? A) One neuron communicates with multiple parts of the brain. B) Axon terminals from multiple input neurons join onto a single postsynaptic neuron. C) An increasing number of neurons are excited down the pathway of the circuit. D) One axon of an input neuron branches to make contact with multiple postsynaptic neurons.

The sensory, or afferent, division of the peripheral nervous system carries information from the brain and spinal cord to effector organs.

The autonomic nervous system carries signals to cardiac muscle, smooth muscle, and glands.

Neurons are responsible for sending and receiving signals referred to as action potentials while neuroglial cells serve a variety of supportive functions.

Bipolar neurons have one axon and one dendrite.

The conduction of an action potential is faster in unmyelinated axons than in myelinated axons.

Regeneration of neural tissue in the PNS is possible only if the neuron's cell body remains intact.

During depolarization, the membrane potential becomes more positive.

During the absolute refractory period, production of an action potential is not possible.

Saltatory conduction is slow due to the presence of insulating myelin around an axon.

Axons with a smaller diameter can conduct nerve impulses more quickly than axons with a larger diameter.

Electrical synapses are faster than chemical synapses due to the presence of gap junctions between cells.

Calcium ion entry into the axon terminal is necessary for the release of neurotransmitter into the synaptic cleft.

Neurotransmitters can be either excitatory or inhibitory depending upon the receptor present on the postsynaptic neuron.

Converting neural circuits are opposite to diverging neural circuits.

Summarize the differences between the somatic motor division and the autonomic nervous system.

Rabies is caused by a virus that attacks the central nervous system. The virus is normally introduced by an animal bite that breaks the surface of the skin. Since the virus is not motile, how does it travel to the central nervous system?

Since Jerry's accident, he has had no sensations in his injured leg. Based on the functional classifications of neurons, explain the type of neuron that has been damaged. Why has he not regained lost nerve function?

Discuss the neuroglial cells that form the myelin sheaths in the CNS and the PNS and some of their differences.

Discuss the type of glial cell that becomes activated within a brain region affected by stroke.

Relate the speed of conduction of an action potential to myelination.

Explain how leak channels and gated channels differ.

Discuss the two main factors involved in the generation of a neuron's resting membrane potential.

The porcupinefish produces a toxin that binds voltage ^-gated sodium channels. Determine the effect of the toxin on nerve function.

Why is a neuron unable to produce an additional action potential during the absolute refractory period?

Discuss the two main factors to influence conduction speed of an action potential.

Discuss the role of calcium ions in the transmission of an action potential at the synapse.

What type of postsynaptic potential would be more likely to promote an action potential ^- an ^IPSP or ^EPSP? Explain.

A postsynaptic neuron is bombarded by synaptic inputs from several hundred presynaptic neurons. However, this neuron does not appear to transmit an impulse. Propose an explanation of why this could occur.

Acetylcholine (ACh) may excite postsynaptic neurons in the CNS; however, it may inhibit some postsynaptic neurons in the PNS. Explain how acetylcholine can be both excitatory and inhibitory.

Kelly takes an antihistamine for allergies. Explain why sleepiness is a side effect of this medicine.

Receptors on a postsynaptic CNS neuron bind glutamate. Describe how the postsynaptic neuron responds.

Explain the purpose of a neuronal pool.

While driving home, Henry watched as a large truck drifted into his lane from oncoming traffic. Henry's central nervous system integrated this information to determine the position of his own vehicle, and then he made a decision to swerve his vehicle closer to the side of the road to avoid a head ^-on collision. From this scenario, determine the sensory information and his motor functions.

Multiple sclerosis (MS) is a disease in which the myelin sheaths are destroyed in the brain and spinal cord. With what process does this interfere and what would be the consequences?

Does a local potential guarantee the creation of an action potential? Explain.

Explain how a polarized neuron differs from a hyperpolarized neuron.

The nerve agent, sarin, was developed during World War II to block the effects of acetylcholinesterase. Explain the effects of this nerve agent on the synapse.

Describe the type of neural circuit that controls skeletal muscle movement.