Anatomy Chapter 12 Practice Questions

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

Schwann cells

Which neurotransmitter has widespread effects on a person's attention and emotional state? A) dopamine B) norepinephrine C) serotonin D) GABA E) endorphins

Serotonin

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

Somatic

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

Spatial summation

At a synapse the 0.2-0.5 milliseconds it takes for calcium influx and neurotransmitter release is called A) latency period. B) synaptic delay. C) recovery period. D) repolarization. E) synaptic diffusion.

Synaptic delay

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

Central

Most neurons lack ________ and so are permanently blocked from undergoing cell division. A) ribosomes B) endoplasmic reticula C) a nucleus D) centrioles E) cytoplasm

Centrioles

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

Conducting action potentials

________ nerves are nerves that connect to the brain. A) Spinal B) Unmyelinated C) Myelinated D) Cranial E) Interneural

Cranial

The following are the steps involved in transmission at a cholinergic synapse. What is the correct sequence for these events? 1. Chemically-gated sodium channels on the postsynaptic membrane are activated. 2. Calcium ions enter the synaptic terminal. 3. Acetylcholinesterase hydrolyzes acetylcholine. 4. An action potential depolarizes the synaptic terminal at the presynaptic membrane. 5. The pre-synaptic terminal reabsorbs choline. 6. Acetylcholine is released from storage vesicles by exocytosis. 7. Acetylcholine binds to receptors on the postsynaptic membrane. 8. Calcium ions are removed from the cytoplasm of the pre- synaptic terminal. A) 4, 2, 6, 7, 8, 5, 3, 1 B) 4, 2, 6, 7, 1, 8, 3, 5 C) 2, 4, 6, 7, 1, 8, 3, 5 D) 2, 5, 4, 6, 7, 1, 8, 3 E) 6, 4, 2, 7, 1, 8, 3, 5

4, 2, 6, 7, 1, 8, 3, 5

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. What is the proper sequence of these events? A) 4, 6, 7, 3, 2, 5, 1 B) 4, 6, 7, 1, 2, 3, 5 C) 6, 7, 4, 1, 2, 3, 5 D) 2, 4, 6, 7, 1, 3, 5 E) 4, 2, 5, 6, 7, 3, 1

4, 6, 7, 1, 2, 3, 5

The period during which an excitable membrane cannot respond to further stimulation is the ________ period. A) relative refractory B) absolute refractory C) resting D) lag E) stationary

Absolute refractory

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

Acetylcholine

The part of the peripheral nervous system that carries sensory information to the CNS is designated A) motor. B) afferent. C) efferent. D) autonomic. E) somatic.

Afferent

The effect that a neurotransmitter has on the postsynaptic membrane depends on the A) frequency of neurotransmitter release. B) nature of the neurotransmitter. C) characteristics of the receptors. D) quantity of neurotransmitters released. E) All of the answers are correct.

All of the answers are correct

The efferent division of the peripheral nervous system innervates ________ cells. A) skeletal muscle B) smooth muscle C) heart muscle D) glandular E) All of the answers are correct.

All of the answers are correct

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

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

All-or-none

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

IPSPs (inhibitory postsynaptic potentials) A) are local depolarizations. B) are local hyperpolarizations. C) increase membrane permeability to sodium ions. D) block the efflux of potassium ions. E) block the efflux of calcium ions.

Are local hyperpolarizations

The axon is connected to the soma at the A) telodendria. B) synaptic terminal. C) collaterals. D) axon hillock. E) synapse.

Axon hillock

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

A threshold stimulus is the A) depolarization necessary to cause an action potential. B) peak of an action potential. C) hyperpolarization of an axon. D) resting membrane potential. E) electrical current that crosses the synaptic cleft.

Depolarization necessary to cause an action potential

A deficiency in which neurotransmitter would cause Parkinson's-like symptoms? A) dopamine B) norepinephrine C) serotonin D) GABA E) endorphins

Dopamine

________ provide information about the external environment. A) Spinal nerves B) Anaxonic neurons C) Internoceptors D) Exteroceptors E) Proprioceptors

Exteroceptors

A neuron whose membrane potential shifts closer to threshold is said to be A) hyperpolarized. B) depolarized. C) facilitated. D) repolarized. E) at equilibrium.

Facilitated

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

Regions of the CNS where neuron cell bodies dominate constitute the ________ matter. A) white B) gray C) neural D) brain E) ganglion

Gray

Voltage-gated sodium channels have both an activation gate and a(n) ________ gate. A) inactivation B) ion C) swinging D) repolarization E) threshold

Inactivation

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

Leak

________ 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

Which of the following is not involved in creating the resting membrane 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 greater than potassium ions D) membrane permeability for potassium ions greater than sodium ions E) The interior of the plasma membrane has an excess of negative charges.

Membrane permeability for sodium ions greater than potassium ions

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

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

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

Multipolar

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

Multipolar

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

Nissl bodies

The tiny gaps between adjacent Schwann cells are called A) neurillema. B) nodes of Ranvier. C) axolemma. D) terminals. E) vesicles.

Nodes of Ranvier

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

Oligodendrocytes

The nervous tissue outside of the central nervous system composes the ________ nervous system. A) somatic B) peripheral C) autonomic D) afferent E) parasympathetic

Peripheral

The release of GABA and subsequent inhibition of voltage gated calcium channels is associated with A) presynaptic inhibition. B) presynaptic facilitation. C) spatial summation. D) temporal summation. E) spatial facilitation.

Presynaptic inhibition

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

Relative refractory

Rapid impulse conduction from "node" to "node" is called A) spatial propagation. B) saltatory propagation. C) divergent propagation. D) synaptic transmission. E) continuous propagation.

Saltatory propagation

Axons terminate in a series of fine extensions known as A) telodendria. B) terminals. C) collaterals. D) dendrites. E) synapses.

Telodendria

When a second EPSP (excitatory postsynaptic potential) 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

Temporal summation

Sensory information from skeletal muscles travels over ________ fibers. A) type A B) type B C) type C D) type D E) type E

Type A

Which of the following types of nerve fiber possesses the fastest speed of impulse propagation? A) type A B) type B C) type C D) type D E) type E

Type A

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

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

Unipolar

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

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