Chapter 12 Quiz and Homework Questions
d
During an action potential of a neuron, what directly causes the different channels to open and close? a. neurotransmitter binding to chemically gated channels b. calcium ions c. sodium and potassium ions d. the transmembrane potential (voltage)
e
A molecule that carries information across a synaptic cleft is a a. synapse. b. receiving neuron. c. sending neuron. d. synaptic cleft. e. neurotransmitter.
d
Around what transmembrane potential does threshold commonly occur? a. -60 V b. -70 mV c. +60 mV d. -60 mV
a
Myelin limits the movement of ions across the axon membrane, so the action potential "jumps" from node to node along the axon. This is an example of what type of propagation? a. saltatory b. graded c. hyperpolarization d. continuous
b
At rest, why is the transmembrane potential of a neuron (-70 mV) closer to the potassium equilibrium potential (-90 mV) than it is to the sodium equilibrium potential (+66 mV)? a. There are more negatively charged proteins inside the cell than outside the cell. b. The membrane is much more permeable to potassium ions than to sodium ions. c. The concentration of potassium ions inside the cell is greater than the concentration of sodium ions outside the cell. d. For each ATP hydrolyzed, the sodium-potassium exchange pump transports more sodium ions out of the cell (three) than it transports potassium ions into the cell (two).
d
Both poliomyelitis and Guillain-Barré syndrome can involve paralysis where control over skeletal muscle function is lost. What is the neurotransmitter that a motor neuron uses to communicate with a skeletal muscle? a. norepinephrine b. dopamine c. gamma aminobutyric acid (GABA) d. acetylcholine
b
Certain details about Mr. Roosevelt's case call into question whether he really suffered from polio. The pathological features that Mr. Roosevelt experienced were much more characteristic of Guillain-Barré syndrome, an autoimmune disease that involves the demyelination of peripheral nerves. Which neuroglia cells form the myelin sheath of motor nerves? a. satellite cells b. Schwann cells c. astrocytes d. ependymal cells
b
Compared to the electrical gradient for sodium at rest, the electrical gradient for potassium at rest is __________. a. in the opposite direction but of the same magnitude. b. in the same direction and of the same magnitude. c. in the same direction but of lesser magnitude. d. in the same direction but of greater magnitude.
a
During an action potential, after the membrane potential reaches +30 mV, which event(s) primarily affect(s) the membrane potential? a. Voltage-gated sodium channels begin to inactivate (close) and voltage-gated potassium channels begin to open. b. Voltage-gated sodium channels begin to inactivate (close). c. Voltage-gated potassium channels begin to open and the sodium-potassium exchange pump begins removing the excess Na+ ions from the inside of the cell. d. Voltage-gated sodium channels begin to inactivate (close) and the sodium-potassium exchange pump begins removing the excess sodium ions from the inside of the cell.
d
Excitatory neurotransmitters cause ___ and inhibitory neurotransmitters cause ___? a. Repolarization/return to resting potential b. Suppression of generation of action potentials/promote generation of action potentials c. Synaptic fatigue/synaptic delay d. Depolarization/hyperpolarization
a
Female gymnasts can contort their bodies in many different ways and land on a 4" beam with accuracy. Which fiber type is responsible for this ability? a. Type A fibers b. Type B fibers c. Type C fibers d. Type D fibers
a
If a nerve cell receives many IPSPs in different locations at the same time, __________. a. it will show spatial summation b. the membrane potential will depolarize c. the nerve cell will approach threshold
d
If a signal from a sending neuron makes the receiving neuron more negative inside, a. the sending neuron becomes more negative inside. b. the sending neuron becomes more positive inside. c. the receiving neuron is more likely to generate an action potential. d. the receiving neuron is less likely to generate an action potential. e. the receiving neuron immediately generates an action potential.
a
In a neuron, sodium and potassium concentrations are maintained by the sodium-potassium exchange pump such that __________. a. the sodium concentration is higher outside the cell than inside the cell and the potassium concentration is higher inside the cell than outside the cell. b. both sodium and potassium concentrations are higher outside the cell compared to inside. c. the sodium concentration is higher inside the cell than outside the cell and the potassium concentration is higher outside the cell than inside the cell. d. the concentration of sodium outside the cell is equal to the concentration of potassium inside the cell.
a
In a typical neuron, what is the equilibrium potential for potassium? a. -90 mV b. -70 mV c. +66 mV d. 0 mV
d
In a typical neuron, what is the equilibrium potential for sodium? a. -70 mV b. -90 mV c. +30 mV d. +66 mV
c
In what part of the neuron does the action potential typically initiate? a. soma (cell body) b. dendrites c. initial segment of the axon d. axon terminals
d
In which cell does a graded potential occur? a. adipocytes b. epithelial cells c. neurons d. It occurs in all the cell types listed.
d
Josh and a bunch of friends decided to see how many people they could squeeze into a small car for a charity event. Once inside, Josh felt it get hot, smelly, and like the air was getting squished out of his lungs. He also noticed aches and pains in his joints. Which of the following statements best describes the type of sensory neurons involved? a. His interoceptors were monitoring his respiratory system. b. His exteroceptors were bringing in information from the outside world. c. The proprioceptors were monitoring the position of his skeletal muscles and joints. d. The interoceptors, exteroceptors, and proprioceptors were all monitoring his condition.
b
Leak channels allow the movement of potassium and sodium ions by what type of membrane transport? a. simple diffusion b. channel-mediated diffusion c. facilitated diffusion d. active transport
b
Norepinephrine, dopamine, and serotonin are all members of which category of neurotransmitter? a. Hormones b. Biogenic amines c. Amino acids d. Neuropeptides
d
Poliomyelitis is caused by a virus that spreads easily in human populations. Most people with polio infections show no symptoms of disease. However, in a small percentage of victims, the virus enters the central nervous system and attacks the motor neurons of the spinal cord. Motor neurons are an example of what type or class of neuron? a. an anaxonic neuron that has processes that are all dendrites b. a unipolar neuron that has a single elongated process, with the cell body located off to the side c. a bipolar neuron that has two processes separated by the cell body d. a multipolar neuron that has two or more dendrites and a single axon
c
Saltatory propagation occurs in _________ axons, in which action potentials _________. a. unmyelinated; move from one node of Ranvier to another b. unmyelinated; spread by depolarizing the adjacent region of the axon membrane c. myelinated; move from one node of Ranvier to another d. myelinated; move continuously along the axon toward the axon hillock
c
The effects of a neurotransmitter on the postsynaptic membrane depends upon ___. a. The time involved in calcium influx b. ACh being broken down into AChE c. The properties of the receptor, not the nature of the neurotransmitter d. None of these is correct
c
The electrochemical gradient for potassium ions when the transmembrane potential is at the resting potential (-70 mV) is caused by what? a. chemical and electrical gradients both going out of the cell b. a chemical gradient going into the cell and an electrical gradient going out of the cell c. a chemical gradient going out of the cell and an electrical gradient going into the cell d. chemical and electrical gradients both going into the cell
d
The electrochemical gradient for sodium ions in a neuron when the transmembrane potential is at the resting potential is caused by what? a. a chemical gradient going into the cell and an electrical gradient going out of the cell b. chemical and electrical gradients both going out of the cell c. a chemical gradient going out of the cell and an electrical gradient going into the cell d. chemical and electrical gradients both going into the cell
c
The generation of an action potential in a neuron requires the presence what type of membrane channels? a. leakage channels b. chemically gated channels c. voltage-gated channels d. membrane channels are not required
b
Which type of gated channel responds to physical distortion of the membrane surface? a. Chemically regulated channels b. Mechanically regulated channels c. Voltage-gated channels d. Passive channels
b
The small space between the sending neuron and the receiving neuron is the a. vesicle. b. synaptic cleft. c. synaptic terminal. d. calcium channel. e. neurotransmitter.
c
The sodium-potassium exchange pump transports potassium and sodium ions in which direction(s)? a. Sodium and potassium ions are both transported into the cell. b. Sodium ions are transported into the cell. Potassium ions are transported out of the cell. c. Sodium ions are transported out of the cell. Potassium ions are transported into the cell. d. Sodium and potassium ions are both transported out of the cell.
a
What causes repolarization of the membrane potential during the action potential of a neuron? a. potassium efflux (leaving the cell) b. sodium efflux (leaving the cell) c. sodium influx (entering the cell) d. potassium influx (entering the cell)
a
What effect would blocking voltage-regulated calcium channels at a cholinergic synapse have on synaptic communication? a. Communication would cease. b. Communication would be enhanced. c. Communication would be misdirected. d. Communication would continue as before.
a
What ion causes repolarization of the neuron during an action potential? a. K+ (potassium) b. Ca2+ (calcium) c. Na+ (sodium) d. Mg2+ (magnesium)
d
What ion is responsible for the depolarization of the neuron during an action potential? a. K+ (potassium) b. Ca2+ (calcium) c. Cl- (chloride) d. Na+ (sodium)
c
What is primarily responsible for the brief hyperpolarization near the end of the action potential? a. voltage-gated sodium channels taking some time to recover from inactivation b. voltage-gated potassium channels opening as the membrane potential becomes more negative (repolarized) c. voltage-gated potassium channels taking some time to close in response to the negative membrane potential d. the sodium/potassium exchange pump taking some time to restore the normal ion concentrations
d
What is the electrochemical gradient of an ion? a. the direction an ion would diffuse (either outward or inward) when the neuron is at rest, regardless of the transmembrane potential b. the difference between the concentrations of an ion inside and outside the cell c. the transmembrane potential at which the electrical and chemical gradients are equal in magnitude, but opposite in direction d. the sum of the electrical and chemical gradients for that ion
c
What is the typical duration of a nerve action potential? a. 200 ms b. 0.2 ms c. 2 ms d. 20 ms
a
What type of membrane transport causes the depolarization phase of the action potential in neurons? a. facilitated diffusion b. active transport c. filtration d. simple diffusion
c
What would damage to the afferent division of the PNS affect? a. Ability to learn new facts b. Ability to experience motor stimuli c. Ability to experience sensory stimuli d. Ability to remember past events
d
When a person has a stroke, blood leaks into the brain tissue. Which type of neuroglia cells would repair the damage? a. oligodendrocytes b. satellite cells c. ependymal cells d. astrocytes
d
When calcium ions enter the synaptic terminal, a. they cause an action potential in the sending neuron. b. neurotransmitter molecules are quickly removed from the synaptic cleft. c. the inside of the receiving neuron becomes more negative. d. they cause vesicles containing neurotransmitter molecules to fuse to the plasma membrane of the sending neuron. e. the inside of the receiving neuron becomes more positive.
a
When neurotransmitter molecules bind to receptors in the plasma membrane of the receiving neuron, a. ion channels in the plasma membrane of the receiving neuron open. b. the receiving neuron becomes more positive inside. c. the receiving neuron becomes more negative inside. d. ion channels in the plasma membrane of the sending neuron open. e. vesicles in the synaptic terminal fuse to the plasma membrane of the sending neuron.
d
When you take a pain reliever, which of the following best describes, in general terms, how this affects the threshold of neurons? a. Taking a pain reliever affects the all-or-none principle of neurons. So, neurons reaching threshold send an action potential at 50%. b. Taking a pain reliever does not affect the threshold of neurons. c. Taking a pain reliever decreases the threshold. d. Taking a pain reliever increases the threshold.
b
Which ion triggers synaptic vesicles to discharge neurotransmitter into the synaptic cleft? a. potassium b. calcium c. magnesium d. sodium
d
Which of the CNS neuroglial cells plays a role in maintaining the blood-brain barrier and repairing damaged neural tissue? a. Satellite cells b. Microglia c. Oligodendrocytes d. Astrocytes
d
Which of the following is/are correct concerning structural classifications of neurons? a. Multipolar neurons control skeletal muscles. b. Bipolar neurons function in the senses of hearing, smell, and vision. c. Anaxonic neurons have indistinguishable axons and dendrites d. All of the above are correct.
b
Which structure of a neuron is capable of propagating an electrical impulse? a. Dendrites b. Axon c. Cell body d. Perikaryon
d
Why is it impossible for continuous propagation to occur along myelinated axons? a. Myelin increases resistance to the flow of ions across the membrane. b. Only nodes along a myelinated axon can respond to a depolarizing stimulus. c. Continuous propagation uses less energy and fewer sodium ions must be pumped out. d. Both a and b are correct.
