topic 5 review with graph
*Most abundant* class of neuron in the central nervous system is ______. A) anaxonic. B) bipolar. C) multipolar. D) pseudopolar. E) unipolar.
*Multi*polar
Neurons that have *several dendrites* & single axon are called A) anaxonic. B) unipolar. C) bipolar. D) tripolar. E) multipolar.
*Multi*polar
________ account for roughly *half of the volume of nervous system*. A) Axons B) Dendrites C) Neuroglia D) Synapses E) Efferent fibers
*Neuro*glia
Clusters of *RER* & free *Ribosomes* in neurons are called A) neurofilaments. B) neurofibrils. C) perikaryon. D) Nissl bodies. E) microglia.
*Nissl Bodies*
Which of the following is *Not* a recognized structural classification for neurons? A) anaxonic B) bipolar C) multipolar D) pseudopolar E) unipolar
*Pseud*opolar
*R*abies virus travels to the CNS via A) anterograde axoplasmic transport. B) retrograde axoplasmic transport. C) blood vessels. D) subcutaneous connective tissue. E) cerebrospinal fluid.
*R*etrograde Axoplasmic transport
Which of the following statements about the *action potential is false*? A) Rapid depolarization phase is caused by the entry of potassium ions. B) During repolarization phase, sodium channels close and potassium channels open. C) During depolarization phase, membrane potential becomes positive. D) During hyperpolarization phase, the ion pumps re-establish the sodium and potassium concentrations across the cell membrane. E) Repolarization occurs as potassium ions leave the axon.
*Rapid depolarization* phase is caused by the entry of *potassium* ions.
Which of the following is a type of Glial Cell found in Peripheral Nervous System? A) astrocytes B) satellite cells C) oligodendrocytes D) microglia E) ependymal cells
*Satellite Cells*
________ nervous system controls *Skeletal Muscles*. A) sympathetic B) parasympathetic C) afferent D) somatic E) autonomic
*Somatic*
*Axons Terminate* in a series of fine extensions known as _______. A) telodendria. B) terminals. C) collaterals. D) dendrites. E) synapses.
*Tel*odendria = (Greek Tree End)
Deteriorating changes in the distal segment of an axon as a result of a break between it & soma is called ________ degeneration. A) neural B) central C) peripheral D) Wallerian E) conduction
*Wall*erian
*Equilibrium potential* for potassium ion occurs at approximately A) -90 mV. B) -70 mV. C) +66 mV. D) 0 mV. E) +30 mV.
-90 mV
Ions can move across the plasma membrane in which of the following ways? A) through voltage-gated channels as in the action potential B) through passive or leak channels C) by ATP-dependent ion pumps like the sodium-potassium exchange pump D) through chemically gated channels as in neuromuscular transmission E) All of the answers are correct.
All of the answers are correct.
Structures labeled "1" are dendrites. Their membranes contain numerous chemically-gated ion channels. A) first statement is true but the second statement is false. B) first statement is false but the second statement is true. C) Both statements are true. D) Both statements are false.
Both statements are true.
Which type of membrane channels are found at label "3"? A) voltage-gated Na+ channels B) voltage-gated K+ channels C) chemically-gated Na+ & K+ channels D) voltage-gated Ca2+ channels E) both voltage-gated Na+ channels & voltage-gated K+ channels
Both voltage-gated Na+ channels & voltage-gated K+ channels
Stimulus that changes a postsynaptic neuron's membrane from resting potential to -85 mV is a(n) ________ stimulus. A) excitatory B) depolarizing C) temporal D) saltatory E) inhibitory
Inhibitory
When *Potassium* channels *open* & ions diffuse through the membrane, A) inside of the membrane will become more positive. B) inside of the membrane will become more negative. C) there will be almost no effect on transmembrane potential. D) membrane will become depolarized. E) membrane will depolarize to threshold.
Inside of the membrane will become more *Negative*
If the permeability of a resting axon to *Sodium ion Increases*, A) membrane potential will repolarize. B) membrane potential will hyperpolarize. C) inward movement of sodium ion will increase. D) outward movement of sodium ion will decrease. E) inward movement of sodium will increase and the membrane will depolarize.
Inward movement of sodium will increase & membrane will depolarize.
*Sodium-Potassium Ion Exchange Pump* A) must reestablish 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 & Potassium opposite to the direction of their electrochemical gradients. E) depends on a hydrogen gradient for energy.
Moves Sodium & Potassium opposite to the direction of their electrochemical gradients.
________ neurons are the most common structural class in the CNS. A) Multipolar B) Anaxonic C) Unipolar D) Bipolar E) Sensory
Multipolar
How would a chemical that prevents the opening of voltage-regulated Na+ channels affect the function of a neuron? A) Neuron will only be able to hyperpolarize. B) Neuron will depolarize more rapidly. C) Action potentials will lack a repolarization phase. D) Neuron will automatically and repeatedly produce graded potentials. E) Neuron will only be capable of producing graded potentials.
Neuron will only be capable of producing *graded potentials*
*Cytoplasm* that surrounds the nucleus of a neuron is called _______. A) protoplasm. B) nucleoplasm. C) sarcoplasm. D) neuroplasm. E) perikaryon.
Perikaryon
During Repolarization of a neuron A) sodium ions move out of the cell. B) potassium ions move out of the cell. C) potassium ions move into the cell. D) both sodium and potassium ions move into the cell. E) sodium ions move into the cell.
Potassium ions move out of the cell. *"In Repolarization, you only have Potassium"*
Neurotransmitters ready for release are stored in synaptic ________. A) telodendria. B) terminals. C) vesicles. D) mitochondria. E) neurosomes.
Vesicles
Part of the peripheral nervous system that carries sensory information *to CNS* is designated. A) motor. B) afferent. C) efferent. D) autonomic. E) somatic.
*A*fferent. *Arrive to CNS* *Efferent: Exit CNS*
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.
*An*axonic
________ neurons form the *A*fferent division of the PNS. A) Visceral sensory B) Sensory C) Neural sensory D) Somatic sensory E) Motor
*S*ensory *"SAME - Sensory Afferent Motor Efferent"*
Rapid impulse conduction from *"Node" to "Node"* is called A) spatial propagation. B) saltatory propagation. C) divergent propagation. D) synaptic transmission. E) continuous propagation.
*Salt*atory Propagation
On which structure do most neuron to neuron communications occur? A) 2 B) 1 C) 3 D) 4 E) 5
1
Which area of the graph shows when *Chemically Gated Sodium* channels are open? A) 3 B) 1 C) 2 D) 5 E) 4
1
Which area of the graph occurs when there is a *sudden rush of sodium ions* into the neuron? A) 1 B) 2 C) 3 D) 4
2
Which area of the graph shows when *Voltage-Gated Sodium* channels are open? A) 2 B) 4 C) 1 D) 5 E) 3
2
Which area of the graph shows when *Potassium Channels* open? A) 1 B) 2 C) 3 D) 4
3
Which part(s) of the neuron can *propagate an action potential*? A) 1 B) 1 and 2 C) 2 and 3 D) 3
3
Which point of the graph shows when *Potassium ion outflow exceeds Sodium* ion inflow? A) 1 B) 2 C) 3 D) 4
3
At the *Normal Resting Potential* of a typical neuron, its sodium-potassium exchange pump transports A) 1 intracellular sodium ion for 2 extracellular potassium ions. B) 2 intracellular sodium ions for 1 extracellular potassium ion. C) 3 intracellular sodium ions for 1 extracellular potassium ion. D) 3 intracellular sodium ions for 2 extracellular potassium ions. E) 3 extracellular sodium ions for 2 intracellular potassium ions.
3 intracellular sodium ions for 2 extracellular potassium ions.
When is the neuron in the refractory period? A) 1 B) 2 C) 3 D) 4
4
Which area of the graph shows when membrane potential approaches the potassium *equilibrium* potential? A) 1 B) 2 C) 3 D) 4
4
Any stimulus that opens a ________ ion channel will produce a graded potential. A) voltage-gated B) chemically gated C) sodium D) mechanically gated E) All of the answers are correct.
All of the answers are correct.
Axoplasm of the axon contains which of the following? A) neurotubules B) mitochondria C) vesicles D) neurofibrils E) All of the answers are correct.
All of the answers are correct.
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.
Function of *Astrocytes* in CNS includes which of the following? A) adjusting composition of interstitial fluid B) guiding neuron development C) maintaining blood-brain barrier D) repairing damaged neural tissue E) All of the answers are correct.
All of the answers are correct.
*Axon is connected* to the soma at _______. A) telodendria. B) synaptic terminal. C) collaterals. D) axon hillock. E) synapse.
Axon *Hill*ock
Following are the main steps in the generation of an action potential. 1. Sodium channels are inactivated. 2. Voltage-gated potassium channels open & potassium moves out of the cell, initiating repolarization. 3. Sodium channels regain their normal properties. 4. Graded depolarization brings an area of an excitable membrane to threshold. 5. Temporary hyperpolarization occurs. 6. Sodium channel activation occurs. 7. Sodium ions enter the cell & 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
B) 4, 6, 7, 1, 2, 3, 5
Neurons that have 1 axon & 1 dendrite, with soma in between, are called A) anaxonic. B) unipolar. C) bipolar. D) tripolar. E) multipolar.
Bipolar.
Raising the potassium ion concentration in the extracellular fluid surrounding a nerve cell will have what effect? A) depolarize it B) hyperpolarize it C) increase the magnitude of the potassium equilibrium potential D) decrease the magnitude of the potassium equilibrium potential E) Both hyperpolarize it & decrease magnitude of potassium equilibrium potential
Both hyperpolarize it & decrease magnitude of potassium equilibrium potential
Integral membrane proteins that connect electrical synapses are called A) connexons. B) receptors. C) desmosomes. D) sodium channels. E) synapsins.
Connexons
Opening of sodium channels in the axon membrane causes A) depolarization. B) repolarization. C) hyperpolarization. D) increased negative charge inside the membrane. E) inhibition.
Depolarization
Threshold stimulus is A) depolarization necessary to cause an action potential. B) peak of an action potential. C) hyperpolarization of an axon. D) resting potential. E) electrical current that crosses the synaptic cleft.
Depolarization necessary to cause an action potential
Which of the following is not a function of the nervous system? A) sense the internal and external environments B) integrate sensory information C) coordinate voluntary and involuntary activities D) direct long-term functions, such as growth E) control peripheral effectors
Direct long-term functions, such as growth
Which of the following is *Not* true regarding establishment of a *neuron's resting potential*? A) Chemical and electrical forces both favor sodium ions entering the cell. B) Electrical forces push sodium ions into the cell. C) Chemical gradient for potassium ions tends to drive them out of the cell. D) Ion pumps in the plasma membrane eject sodium ions as fast as they cross the membrane. E) Resting membrane permeability to Na+ is very low.
Electrical forces push sodium ions into the cell
What is occurring at the area labeled #4? A) An inhibitory stimulus has occurred. B) Chemically gated potassium channels have opened. C) Excessive potassium has diffused out causing hyperpolarization. D) Sodium ions have been pumped out of the neuron. E) Excessive depolarization of the axon has occurred.
Excessive potassium has diffused out causing *Hyperpolarization*.
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*
Voltage-gated channels are present A) at the motor end plate. B) on the surface of dendrites. C) in the membrane that covers axons. D) on the soma of neurons. E) along the perikaryon of neurons.
In the membrane that covers axons.
Voltage-gated sodium channels have both an activation gate & a(n) ________ gate. A) inactivation B) ion C) swinging D) repolarization E) threshold
Inactivation
________ are the most numerous type of neuron in the CNS. A) Sensory neurons B) Motor neurons C) Unipolar neurons D) Bipolar neurons E) Interneurons
Interneurons
If the sodium-potassium pumps in the plasma membrane fail to function, all of the following occur *Except* A) intracellular concentration of potassium ions will increase. B) neuron will slowly depolarize. C) membrane will slowly lose its capacity to generate action potentials. D) inside of the membrane will have a resting potential that is more positive than normal. E) intracellular concentration of sodium ions will increase
Intracellular concentration of potassium ions will increase.
Which of the following is true about *Threshold* for an Action potential? A) It is more positive than the resting potential. B) Voltage-gated potassium channels begin to close. C) Voltage-gated potassium channels begin to open. D) The membrane begins to hyperpolarize. E) Threshold for a typical neuron is approximately -30 mV.
It is *more positive* than Resting Potential
How would the *Absolute refractory period* be affected if voltage-regulated sodium channels failed to inactivate? A) It would last indefinitely. B) It would be much briefer. C) It would be basically unaffected.
It would last *indefinitely*
________ 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 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) interior of the plasma membrane has an excess of negative charges.
Membrane permeability for sodium ions greater than potassium ions
Structure labeled "2" is a(n) A) neurofilament. B) dendrite. C) initial segment. D) perikaryon. E) axon.
Neurofilament.
In CNS, glia cell include:
Oligodendrocytes. Ependymal Cells. Astrocytes.
Oligodendroglia FCN
Provide the insulation (myelin) to neurons in CNS
Schwann Cell FCN
Provide the insulation (myelin) to neurons in PNS
In PNS, glia cell include:
Schwann cells in nerves Satellite cells in ganglia.
Which of the following activities or sensations is/are not monitored by *interoceptors*? A) sight B) taste C) activities of the digestive system D) cardiovascular activities E) urinary activities
Sight
What is occurring in the area between #2 & #3? A) Excitatory graded potential is occurring. B) Potassium ions are entering the axon & causing depolarization. C) Chemically gated sodium channels are open & sodium is diffusing into the axon. D) Sodium ions are entering the axon & causing depolarization. E) Repolarization of the axon due to sodium ions leaving the axon is occurring.
Sodium ions are entering the axon & causing depolarization.
How does blocking retrograde axoplasmic transport in an axon affect the activity of a neuron? A) The neuron becomes unable to produce neurotransmitters. B) The neuron becomes unable to produce action potentials. C) The soma becomes unable to export products to the synaptic terminals. D) The soma becomes unable to respond to changes in the distal end of the axon. E) The neuron becomes unable to depolarize when stimulated.
Soma becomes unable to respond to changes in the distal end of the axon.
If the axolemma becomes more permeable to potassium ion, A) membrane will depolarize to threshold. B) stronger stimulus will be required to cause an action potential. C) membrane will depolarize to +30 mV. D) sodium ions will enter the cell to replace the lost potassium ions. E) inside of the membrane will have a positive charge.
Stronger stimulus will be required to cause an action potential.
Site of intercellular communication* between a neuron & another cell* is _______. A) telodendria. B) synaptic terminals. C) collateral. D) hillock. E) synapse.
Synapse
Identify the structure labeled "5." A) axons B) telodendria C) dendritic spines D) synaptic terminals E) collateral branch
Synaptic terminals
Identify the structure labeled "4." A) synaptic terminals B) telodendria C) dendritic spines D) collateral branches E) axons
Telodendria
In a(n) ________ neuron, the dendrites & axon are continuous or fused. A) multipolar B) anaxonic C) unipolar D) bipolar E) interneuron
Unipolar
Neurons in which dendritic & axonal processes are continuous & 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
*Glial cells (aka Neuroglia)*
are non-neuronal cells that maintain homeostasis, form myelin. provide support. protection for neurons in the central nervous system. peripheral nervous system.
Graded potentials A) produce an effect that increases with distance from the point of stimulation. B) produce an effect that spreads actively across the membrane surface. C) may be either a depolarization or a hyperpolarization. D) are often all-or-none. E) cause repolarization.
may be either a depolarization or a hyperpolarization.
In PNS, glia derive from the _____.
neural crest
In CNS, glia develop from _____.
neural tube
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
Most *CNS neurons lack centrioles*. This observation explains A) why CNS neurons grow such long axons. B) why CNS neurons cannot divide to regenerate damaged tissue. C) ability of neurons to generate an action potential. D) ability of neurons to communicate with each other. E) ability of neurons to produce a resting potential.
why CNS neurons *cannot divide* to regenerate damaged tissue.
*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) 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.
________ neurons are small and have *no anatomical features that distinguish dendrites from axons*. A) Multipolar B) Anaxonic C) Unipolar D) Bipolar E) Sensory
*An*axonic
Neuroglial cells that participate in *maintaining Blood-Brain Barrier* are A) astrocytes. B) ependymal cells. C) microglia. D) oligodendrocytes. E) Schwann cells.
*Astrocytes*
________ neurons are short, with a *cell body between dendrite & axon*, & occur in special sense organs. A) Multipolar B) Anaxonic C) Unipolar D) Bipolar E) Motor
*Bi*polar
Branches that may occur *Along an Axon* are called A) telodendria. B) synaptic terminals. C) collaterals. D) hillocks. E) synapses.
*Collaterals*
Microglia FCN
*Digest* parts of *dead* neurons.
Ion channels that are *always open* are called ________ channels. A) active B) gated C) leak D) regulated E) local
*Leak*
Puffer fish poison blocks voltage-gated sodium channels like a cork. What effect would this neurotoxin have on the function of neurons? A) Neurons would depolarize more rapidly. B) Action potentials would lack a repolarization phase. C) absolute refractory period would be shorter than normal. D) Axon would be unable to generate action potentials. E) None, because the chemically gated sodium channels would still function.
Axon would be unable to generate action potentials
________ nervous system is composed of the brain & spinal cord. A) autonomic B) peripheral C) central D) efferent E) afferent
Central
________ open or close in response to binding specific molecules. A) Leak channels B) Activated channels C) Chemically gated channels D) Voltage-gated channels E) Voltage-gated and chemically gated channels
Chemically gated channels
If acetylcholine (ACh) causes inhibition of a postsynaptic neuron, to what type of membrane channel did the ACh bind? A) mechanically-regulated channel B) voltage-regulated sodium channel C) voltage-regulated calcium channel D) chemically-regulated potassium channel E) chemically-regulated sodium channel
Chemically-regulated potassium channel
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
What is contained inside the structure labeled "5"? A) neuroglia B) sodium ions C) acetylcholinesterase D) calcium ions E) neurotransmitter molecules
Neurotransmitter molecules
Largest & most numerous of Glial cells in the central nervous system are A) astrocytes. B) satellite cells. C) oligodendrocytes. D) microglia. E) ependymal cells.
*Astro*cytes
After a stroke, what type of *Glial Cell* accumulates within the affected brain region? A) Schwann cells B) satellite cells C) oligodendrocytes D) microglia E) ependymal cells
*Micro*glia
Same ________ can have different effects depending on the properties of the ________. A) neurotransmitter; receptor B) receptor; neurotransmitter C) substrate; receptor D) hormone; neurotransmitter E) propagation; neurotransmitter
Neurotransmitter; receptor
Which of the following is not a function of Neuroglia? A) support B) memory C) secretion of cerebrospinal fluid D) maintenance of blood-brain barrier E) phagocytosis
Memory
Satellite Cells FCN
Physical support to neurons in PNS
