Q&A Hero

Q: Where are unmyelinated nerve fibers surrounded by Schwann cells? A. In the PNS B. In the CNS C. In the PNS and CNS D. Nowhere. Unmyelinated nerve fibers are never surrounded by Schwann cells.

Q: Which of the following is true regarding unmyelinated nerve fibers in the PNS? A. A Schwann cell folds its plasma membrane around several fibers . B. A Schwann cells wraps its plasma membrane around each individual fiber as it does with myelinated fibers. C. An oligodendrocyte cells wraps its plasma membrane around each fiber as it does with myelinated fibers. D. Satellite cells cluster around each axon to form a pseudo-myelin sheath.

Q: In PNS nerve fiber regeneration, how is a growing axon directed to its original destination? A. It grows within a regeneration tube. B. The axonal terminals grow towards the soma until the two severed fragments are reunited. C. The axon grows a collateral that is directed by growth factors secreted by the postsynaptic neuron. D. Injured Schwann cells produce a trail of prostaglandins to the original destination.

Q: If the potassium leak channels were suddenly blocked in a resting neuron, what would happen to its resting membrane potential? A. It would become more positive. B. It would become more negative. C. The RMP would be unaffected. D. It would hyperpolarize.

Q: Where does saltatory conduction occur? A. From node to node in myelinated fibers B. From node to node in unmyelinated fibers C. Down the entire length of a myelinated fiber D. Down the entire length of an unmyelinated fiber

Q: Place the following events in synaptic transmission at a cholinergic synapse in order: A - A postsynaptic potential is produced; B - Voltage gated calcium channels open and calcium enters the cell; C - ACh is released and diffuses across the synaptic cleft; D - A nerve signal arrives at a synaptic knob; E - Ligand gated sodium channels open and sodium enters the cell. A. D, B, C, E, A B. D, B, E, A, C C. B, C, D, E, A D. B, D, C, A, E

Q: Place the following events of synaptic transmission at an adrenergic synapse in order: A - ATP is converted to cAMP B - The cell's metabolism is altered C - G protein binds adenylate cylase D - The G protein dissociates E - NE binds the receptor A. E, D, C, A, B B. E, D, A, C, B C. D, E, C, A, B D. D, E, A, C, B

Q: The respiratory center gathers information from a variety of sources in order to set the rate and depth of breathing. This is an example of what type of neural circuit? A. Convergent B. Divergent C. Reverberating D. Parallel after-discharge

Q: Ascending signals in the spinal cord travel via gray matter, while descending signals travel via white matter.

Q: Cervical and lumbar enlargements are wide points in the spinal cord marking the emergence of motor nerves.

Q: Each portion of the spinal cord, from which a spinal nerve emerges, is called a "segment" of the cord.

Q: Nerve fibers in a given white matter tract are similar in origin, destination, and function.

Q: Voluntary motor signals typically begin in an upper motor neuron in the thalamus.

Q: Most nerves are motor nerves.

Q: A nerve fiber is enclosed in its own fibrous sleeve called perineurium.

Q: How does a neuron transport enzymes produced in the soma to its axon terminals? A. Along microtubules B. By diffusion C. Via cytoplasmic streaming D. Through co-transport

Q: Inhibitory postsynaptic potentials (IPSPs) are associated with which of the following? A. Depolarization of the cell membrane B. Repolarization of the cell membrane C. Hyperpolarization of the cell membrane D. No change in the cell membrane potential E. No change of the threshold

Q: The opening of __________ gates produces an __________. A. chloride; IPSP B. sodium; IPSP C. calcium; IPSP D. potassium; EPSP E. calcium and sodium; IPSP

Q: Which of these is an example of an EPSP in a typical neuron? A. A voltage change from 0 mV to +0.35 mV B. A voltage change from -70 mV to -69.5 mV C. A voltage change from -69.5 mV to -70 mV D. A voltage change from +35 mV to 0 mV E. A voltage change from -70 mV to -70.5 mV

Q: A neuron can receive thousands of EPSPs from different neurons, and responds by triggering or not triggering an action potential. This addition and response to the net effect of postsynaptic potentials is called __________. A. temporal summation B. neural summation C. spatial summation D. neuronal coding E. recruitment

Q: What is the opposite of presynaptic inhibition? A. Coding B. Integration C. Recruitment D. Summation E. Facilitation

Q: What type of neural circuit is best for producing a prolonged output? A. A converging circuit B. A diverging circuit C. A reverberating circuit D. A presynaptic pool E. An autonomic pool

Q: Even though all action potentials are the same, the brain can differentiate a variety of stimuli by source and intensity. The mechanism by which the nervous system converts these action potentials into meaningful information is called neural __________. A. recruitment B. pooling C. integration D. facilitation E. coding

Q: Accumulation of Ca2+ in the synaptic knob is called __________, and probably plays an important role in __________. A. synaptic facilitation; short-term memory B. neural coding; immediate memory C. postsynaptic potential; long-term memory D. neural coding; short-term memory E. long-term potentiation; long-term memory

Q: While both systems maintain homeostasis, how does the nervous system differ from the endocrine system? A. The nervous system releases neurotransmitters between cells, while the endocrine system releases hormones into the blood. B. The nervous system releases neurotransmitters into the blood, while the endocrine system releases hormones between cells. C. The nervous system releases hormones between cells, while the endocrine system releases neurotransmitters into the blood. D. The nervous system releases hormones into the blood, while the endocrine system releases neurotransmitters between cells.

Q: Which body system(s) is(are) dedicated to maintaining stable internal conditions by detecting and responding to stimuli? A. Nervous and endocrine B. Nervous C. Endocrine D. Nervous, endocrine, and integumentary

Q: What property of neurons allows them to respond to changes in the environment? A. Excitablity B. Conductivity C. Secretion D. Permeability

Q: If a neuron is prevented from sending a neurotransmitter across a synapse to another cell, which neuron property is being inhibited? A. Secretion B. Excitability C. Conductivity D. Permeability

Q: Which of these happens first in an adrenergic synaptic transmission? A. ATP is converted to cyclic AMP B. Adenylate cyclase is activated C. G protein dissociates from the NE receptor D. G protein binds to adenylate cyclase E. Cyclic AMP induces several effects in the cell

Q: Some antidepressant drugs act by inhibiting monoamine oxidase (MAO). What is the function of this enzyme? A. It binds to chloride gates. B. It breaks down monoamines. C. It blocks sodium channels. D. It converts ATP to cyclic AMP. E. It degrades acetylcholine.

Q: Which of these does not contribute to the cessation of the signal in a synaptic transmission? A. Synaptic vesicles secrete neurotransmitter by exocytosis. B. Neurotransmitter escapes from the synapse into the nearby extracellular fluid. C. Neurotransmitters are no longer released. D. The synaptic knob reabsorbs some neurotransmitters by endocytosis. E. Enzymes in the postsynaptic cell break down some neurotransmitters.

Q: Which neurotransmitter excites skeletal muscle and inhibits cardiac muscle? A. Norepinephrine B. Dopamine C. Histamine D. Acetylcholine E. b-endorphin

Q: A neuron receives a stimulus. Which of the following events happens next? A. A local potential develops B. Threshold is reached C. Hyperpolarization of the membrane D. Repolarization of the membrane E. A resting membrane potential is established

Q: In an action potential, which event directly follows repolarization? A. Threshold is reached B. Hyperpolarization of the membrane C. Depolarization of the membrane D. Hypopolarization of the membrane E. The resting membrane potential is reinstated

Q: Local potentials are __________, whereas action potentials are __________. A. irreversible; reversible B. self-propagating; local C. graded; all or none D. nondecremental; decremental E. produced by voltage-regulated channels; produced by gated channels

Q: What occurs during hyperpolarization of a neuron membrane? A. Sodium ions are entering the cells B. Sodium ions are leaving the cell C. Potassium ions are entering the cell D. Potassium ions are leaving the cell E. Both sodium and potassium ions are leaving the cell

Q: During the absolute refractory period which of the following is true? A. If a neuron reaches threshold, the action potential goes to completion. B. The neuron fires at its maximum voltage if a stimulus depolarizes the neuron to threshold. C. The signal grows weaker with distance. D. It is possible to trigger a new action potential, but only with an unusually strong stimulus. E. No stimulus of any strength will trigger a new action potential.

Q: A traveling wave of excitation is known as a(n) __________. A. local potential B. graded potential C. action potential D. nerve signal E. depolarizing signal

Q: What would be the best explanation for why myelinated fibers conduct signals faster than unmyelinated fibers? A. There are no internodes in unmyelinated fibers. B. There are more internodes in unmyelinated fibers. C. Facilitated diffusion of sodium and potassium is faster in myelinated fibers. D. Active transport of sodium and potassium is faster in myelinated fibers. E. Diffusion of ions along the axoplasm is faster.

Q: All of the following are typical characteristics of neurotransmitters except __________. A. they are synthesized by a presynaptic neuron B. they are released in response to stimulation C. they are released into the bloodstream before reaching the postsynaptic cell D. they bind to specific receptors on the postsynaptic cell E. they alter the physiology of the postsynaptic cell

Q: A cholinergic synapse uses __________ as its neurotransmitter. A. monoamine B. acetylcholine C. epinephrine D. norepinephrine E. catecholamine

Q: What is the most common inhibitory neurotransmitter in the brain? A. g-aminobutyric acid (GABA) B. Noradrenaline C. Epinephrine D. Acetylcholine E. Norepinephrine

Q: Which of these happens first in an cholinergic synaptic transmission? A. Acetylcholine diffuses across the synaptic cleft B. A postsynaptic potential is produced C. Sodium enters the postsynaptic cell D. The synaptic vesicles release acetylcholine E. Acetylcholine binds to ligand-regulated gates

Q: In a neuron, the opening of sodium gates typically leads to __________. A. repolarization of the plasma membrane B. hyperpolarization of the plasma membrane C. depolarization of the plasma membrane D. drifting of plasma membrane voltage toward a more negative value E. plasma membrane voltage returning to the resting membrane potential

Q: Which of the following will cause the plasma membrane to hyperpolarize when at its RMP? A. An inflow of sodium B. An inflow of potassium C. An inflow of calcium D. An inflow of chloride E. An outflow of chloride

Q: Local potentials are __________, meaning they vary in magnitude according to the strength of the stimulus. A. stabile B. graded C. self propagating D. excitatory E. inhibitory

Q: An inhibitory local potential causes which of the following? A. Depolarization of the plasma membrane B. Hyperpolarization of the plasma membrane C. Repolarization of the plasma membrane D. Neutralization of the plasma membrane E. Drifting of the membrane potential towards the resting membrane potential

Q: While a neuron membrane is depolarizing its __________. A. chloride gates are partially open B. chloride gates are fully open C. potassium gates are fully open D. sodium gates are partially open E. sodium gates are fully open

Q: Which glial cell is found wrapped around nerve fibers in the PNS? A. Oligodendrocytes B. Schwann cells C. Satellite cells D. Nodes of Ranvier E. Ependymal cells

Q: In which part of a neuron is the postsynaptic membrane usually found? A. Synaptic knob B. Axon C. Dendrite D. Perikaryon E. Axon collateral

Q: What is the primary site on a neuron for receiving signals from other neurons? A. The synaptic knobs B. The axons C. The axon collaterals D. The somas E. The dendrites

Q: Which cells form myelin in the spinal cord? A. Schwann cells B. Astrocytes C. Satellite cells D. Oligodendrocytes E. Microglia

Q: A myelin sheath is composed primarily of __________. A. lipids B. carbohydrates C. glycoproteins D. proteins E. polysaccharides

Q: Conduction of a nerve impulse would be the fastest in which of the following? A. A large diameter myelinated fiber B. A small diameter myelinated fiber C. A large unmyelinated fiber D. A small unmyelinated fiber E. A small fiber with multiple Schwann cells

Q: In order to regenerate, a peripheral nerve fiber must have which of the following? A. All dendrites intact B. At least half the length of the fiber intact C. At least the entire axon and neurilemma intact D. The soma and at least some neurilemma intact E. At least part of the soma intact

Q: Which of the following ions has the greatest influence on the resting membrane potential? A. Sodium B. Chloride C. Calcium D. Phosphate E. Potassium

Q: Where do most local potentials form in a neuron? A. The dendrites B. The somas C. The axon hillock D. The trigger zone E. The Schwann cells

Q: What is another name for the autonomic nervous system? A. Visceral sensory division B. Somatic sensory division C. Visceral motor division D. Somatic motor division E. Central nervous system

Q: Nerves are __________ of the nervous system. A. organs B. tissues C. organ systems D. organelles E. cells

Q: Some __________ neurons are specialized to detect stimuli, whereas __________ neurons send signals to the effectors of the nervous system. A. efferent; afferent B. afferent; efferent C. motor; sensory D. efferent; association E. afferent; association

Q: About 90% of the neurons in the nervous system are __________ neurons. A. sensory B. motor C. afferent D. efferent E. association

Q: What is the most common type of neuron? A. Multipolar B. Bipolar C. Unipolar D. Anaxonic E. Dendritic

Q: The term "nerve fiber" refers to a(n) __________. A. nerve cell B. organelle in nerve cells C. organ D. axon E. bundle of macromolecules in nerve cells

Q: Most metabolic and regulatory functions in a neuron happen where? A. The axon B. The soma C. The dendrites D. The axon hillock E. The Schwann cell

Q: Acetylcholine triggers the synthesis of the second messenger cAMP only in neurons of the PNS.

Q: Nitric oxide (NO) acts as a neuromodulator by altering synaptic function.

Q: Any two EPSPs will override one IPSP.

Q: Memories are formed by neural pathways of modified synapses.

Q: The __________ division carries signals to the smooth muscle in the large intestine. A. visceral sensory B. somatic sensory C. visceral motor D. somatic motor E. afferent

Q: The __________ division tends to prepare the body for action. A. sensory afferent B. motor afferent C. somatic motor D. parasympathetic E. sympathetic

Q: Which of the following are effectors? A. Receptors B. Stimuli C. Reflexes D. Glands E. Sense organs

Q: Most neurons have multiple dendrites.

Q: Neurons move material away from the soma by retrograde transport.

Q: Unipolar neurons have only a single process leading away from the soma.

Q: Oligodendrocytes serve the same purpose in the CNS that satellite cells do in the PNS.

Q: Ependymal cells line the inner cavities of the CNS.

Q: In the brain, neurons are more abundant than neuroglia.

Q: An action potential never occurs in dendrites. TRUE Gradable: automatic 9. When a neuron is stimulated, Na+ gates open and allow Na+ to exit the cell. FALSE Gradable: automatic

Q: In a myelinated fiber, only the initial segment in the trigger zone has voltage-regulated channels.

Q: Norepinephrine is a monoamine.