 |
| 1 | |
A neuron generally has all of the following principle areas except |
| | A) | microvilli. |
| | B) | a cell body. |
| | C) | dendrites. |
| | D) | an axon. |
|
|
|
| 2 | |
Which of the following is not a function of neurons? |
| | A) | Respond to physical and chemical stimuli. |
| | B) | Conduct electrical impulses. |
| | C) | Release specific chemical regulators. |
| | D) | All of these are neuron functions. |
|
|
|
| 3 | |
Densely staining areas or Nissl bodies of the cell body are composed of |
| | A) | mitochondria. |
| | B) | rough endoplasmic reticulum. |
| | C) | Golgi apparatus. |
| | D) | microfilaments and microtubules. |
|
|
|
| 4 | |
A grouping of cell bodies located within the central nervous system is known as a |
| | A) | tract. |
| | B) | nerve. |
| | C) | nucleus. |
| | D) | ganglion. |
|
|
|
| 5 | |
The numerous, small extensions from the soma are known as the |
| | A) | axons. |
| | B) | axon hillocks. |
| | C) | axon collaterals. |
| | D) | dendrites. |
|
|
|
| 6 | |
A(n) ____ neuron transmits impulses from the periphery to the central nervous system. |
| | A) | association |
| | B) | sensory |
| | C) | motor |
| | D) | ganglion |
|
|
|
| 7 | |
Involuntary effectors (glands, smooth or cardiac muscle) are innervated (stimulated by) |
| | A) | autonomic neurons. |
| | B) | efferent neurons. |
| | C) | motor neurons. |
| | D) | association neurons. |
|
|
|
| 8 | |
Structurally, the type of neurons that act as sensory neurons are the ____ neurons. |
| | A) | bipolar |
| | B) | multipolar |
| | C) | pseudounipolar |
|
|
|
| 9 | |
Myelin sheaths around axons located within the CNS are formed by |
| | A) | Schwann cells. |
| | B) | microglia. |
| | C) | astrocytes. |
| | D) | oligodendrocytes. |
|
|
|
| 10 | |
Which of the following cell types is not a supporting cell or glial cell of the nervous system? |
| | A) | Schwann cell |
| | B) | oligodendrocyte |
| | C) | astrocyte |
| | D) | association neuron |
|
|
|
| 11 | |
The glial cells in the CNS which are capable of phagocytosis are |
| | A) | astrocytes. |
| | B) | oligodendrocytes. |
| | C) | satellite cells. |
| | D) | microglia. |
|
|
|
| 12 | |
Within the central nervous system astrocytes are responsible for |
| | A) | myelinateing axons. |
| | B) | producing cerebrospinal fluid. |
| | C) | phagocytizing particulate matter |
| | D) | aid in synapse formation. |
|
|
|
| 13 | |
The specialized cells of the PNS that are surrounded by a basement membrane that is capable of forming a regeneration tube through which a severed peripheral axon can regrow are the |
| | A) | Schwann cells. |
| | B) | oligodendrocytes. |
| | C) | microglia. |
| | D) | astrocytes. |
|
|
|
| 14 | |
In the developing fetal nervous system, development of the sensory neurons requires the actions of |
| | A) | glial-derived neurotropic factor. |
| | B) | neurotrophin-3. |
| | C) | neurtrophin-4. |
| | D) | neurotrophin-5. |
|
|
|
| 15 | |
The production and release of lactate to provide energy to the neurons is a function of the |
| | A) | microglia. |
| | B) | astrocytes. |
| | C) | oligodendrocytes. |
| | D) | satellite cells. |
|
|
|
| 16 | |
The brain cells forming perivascular feet that interact with blood capillaries and thereby contribute to the structure and function of the blood-brain barrier are the |
| | A) | microglia. |
| | B) | astrocytes. |
| | C) | oligodendrocytes. |
| | D) | satellite cells. |
|
|
|
| 17 | |
In the absence of stimuli, all cells in the body maintain a potential difference across the membrane called the _____, in which the inside of the cell is negatively charged in comparison to the outside of the cell. |
| | A) | action potential |
| | B) | threshold potential |
| | C) | resting membrane potential |
| | D) | graded potential |
|
|
|
| 18 | |
If a resting neuron is stimulated and there is an inward flow of negative charges into the cell, the line recorded on an oscilloscope will |
| | A) | move upward away from the resting potential and toward zero. |
| | B) | move downward away from the resting potential away from zero. |
| | C) | stay constant at the resting potential. |
| | D) | oscillate up and down in a wave-like fashion. |
|
|
|
| 19 | |
The term "voltage regulated" means that the membrane |
| | A) | voltage gated ion channels open and close with changes in the membrane potential. |
| | B) | potential is controlled by the Na+/K+ pumps. |
| | C) | gates will not respond unless the voltage is "regular." |
| | D) | potential can only be controlled by an oscilloscope. |
|
|
|
| 20 | |
Arrange these action potential events in their proper sequence:
- threshold voltage is reached
- K+ gates begin to open
- K+ gates close
- Na+ gates begin to open
- Na+ gates begin to close
- membrane repolarization begins
|
| | A) | 1, 2, 4, 3, 5, 6 |
| | B) | 4, 6, 3, 2, 1, 5 |
| | C) | 4, 6, 2, 1, 5, 3 |
| | D) | 1, 4, 2, 5, 6, 3 |
|
|
|
| 21 | |
Which statement about the action potential or nerve impulse is false? |
| | A) | Only a relatively small number of Na+ and K+ ions actually diffuse across the membrane. |
| | B) | This event includes both positive and negative feedback loops. |
| | C) | The Na+/K+ pumps are directly involved in creating the action potential. |
| | D) | During an action potential, the Na+ and K+ total concentrations are not significantly changed. |
|
|
|
| 22 | |
The diffusion of K+ out of the cell makes the inside of the cell less positive, or more negative, and acts to restore the original resting membrane potential -a process called |
| | A) | depolarization. |
| | B) | hyperpolarization. |
| | C) | repolarization. |
| | D) | overshoot. |
|
|
|
| 23 | |
Both the depolarization and repolarization changes that occur during the action potential are produced by |
| | A) | simple diffusion of ions down their concentration gradients. |
| | B) | active transport pumps along the neuron membrane. |
| | C) | negative feedback loops. |
| | D) | carrier mediated transport. |
|
|
|
| 24 | |
Local anesthetics |
| | A) | block the closure of voltage regulated potassium ion channels. |
| | B) | stimulate the opening of voltage regulated potassium ion channels. |
| | C) | block the opening of voltage regulated sodium ion channels. |
| | D) | stimulate the opening of voltage regulated sodium ion channels. |
|
|
|
| 25 | |
As the intensity of stimulation increases, more and more nerve fibers will become activated -a process called |
| | A) | frequency modulation. |
| | B) | amplitude modulation. |
| | C) | cable properties of the neuron. |
| | D) | recruitment. |
|
|
|
| 26 | |
During the absolute refractory period along an axon membrane of a neuron, |
| | A) | the potassium gates are open and K+ is diffusing down its concentration gradient. |
| | B) | the sodium gates are closed and Na+ is diffusing down its concentration gradient. |
| | C) | the neuron is unable to respond to a stimulus of any intensity. |
| | D) | the membrane is most sensitive to stimuli. |
|
|
|
| 27 | |
Nerve impulses (action potentials) are conducted along an axon without decrement. This means the action potentials are conducted without |
| | A) | decreasing velocity. |
| | B) | altering the threshold potential. |
| | C) | decreasing amplitude. |
| | D) | altering the Na+ or K+ concentrations in the neuron. |
|
|
|
| 28 | |
Which of the following statements about the conduction velocity of action potentials along myelinated axons as compared to that along unmyelinated axons, is false? |
| | A) | Conduction velocity is very fast, approaching 225 miles per hour. |
| | B) | Cable properties within the axon help increase the conduction velocity. |
| | C) | Nodes of Ranvier increase the conduction velocity by saltatory conduction. |
| | D) | Thinner fibers conduct action potentials faster than thicker fibers. |
|
|
|
| 29 | |
Which of the following is not a neuron-neuron synapse? |
| | A) | neuromuscular junction |
| | B) | axosomatic synapse |
| | C) | axoaxonic synapse |
| | D) | dendrodentritic synapse |
|
|
|
| 30 | |
Electrical synapses |
| | A) | occur when two cells are joined by integrin proteins. |
| | B) | are characterized by a synaptic cleft. |
| | C) | occur between two cells of unequal size. |
| | D) | require the presence of gap junctions. |
|
|
|
| 31 | |
The small membrane-enclosed compartments that hold and release the neurotransmitter molecules from within the presynaptic neuron, are called |
| | A) | synaptic vesicles. |
| | B) | synaptic clefts. |
| | C) | terminal boutons. |
| | D) | gap junctions. |
|
|
|
| 32 | |
As the intensity of the stimulus in a presynaptic neuron increases, the number of vesicles undergoing exocytosis ___, and the number of released neurotransmitter molecules ____. |
| | A) | increases; increases |
| | B) | increases; decreases |
| | C) | decreases; increases |
| | D) | decreases; decreases |
|
|
|
| 33 | |
The ion that must flow into the presynaptic neuron ending through voltage-regulated channels to activate the release of neurotransmitter chemicals from synaptic vesicles is |
| | A) | sodium. |
| | B) | potassium. |
| | C) | calcium. |
| | D) | iron. |
|
|
|
| 34 | |
Which event is not involved in the release of neurotransmitter chemicals from the presynaptic terminal boutons following the arrival of action potentials? |
| | A) | Phosphorylation of synapsin proteins in the membrane of the synaptic vesicles. |
| | B) | Turning off the Na+/K+ membrane pumps. |
| | C) | Activation of intracellular enzymes (protein kinases) by calmodulin regulatory protein. |
| | D) | Exocytosis of membrane-bound vesicles. |
|
|
|
| 35 | |
When the neurotransmitter molecules released from the presynaptic axon terminals have diffused across the synaptic cleft and have reached the postsynaptic membrane, they |
| | A) | activate electrical synapses or gap junctions. |
| | B) | open voltage-regulated Ca2+ channels promoting the influx of calcium ions. |
| | C) | bind to specific receptor proteins which stimulates the opening of chemically-regulated ion channels. |
| | D) | are absorbed by endocytosis into the postsynaptic membrane and reutilized. |
|
|
|
| 36 | |
If a neurotransmitter binds to a receptor on the target cell and produces depolarizations, the neurotransmitter |
| | A) | was probably stimulating the flow of K+ ions out of the cell. |
| | B) | produced an excitatory postsynaptic potential. |
| | C) | produced an inhibitory postsynaptic potential. |
| | D) | was probably stimulating the flow of Cl- ions into the cell. |
|
|
|
| 37 | |
All of these neurons release acetylcholine as a neurotransmitter except |
| | A) | specific CNS neuron endings. |
| | B) | somatic motor neurons at the neuromuscular junction. |
| | C) | specific autonomic neuron endings, may be either excitatory or inhibitory. |
| | D) | specific cardiac and smooth muscle fibers. |
|
|
|
| 38 | |
Which of the following is not a property of chemically regulated gates? |
| | A) | They respond best to membrane potential changes, such as depolarization. |
| | B) | They are located on the postsynaptic membrane. |
| | C) | They may allow Na+ and K+ diffusion through ion channels simultaneously. |
| | D) | They are activated by neurotransmitters binding to specific receptor molecules. |
|
|
|
| 39 | |
Which of the following statements describes nicotinic acetylcholine (ACh) receptors, as opposed to muscarinc ACh receptors? |
| | A) | Nicotinic receptors have only a single subunit, binding only one ACh molecule. |
| | B) | Nicotinic receptors activate G-protein complexes located in the cell membrane. |
| | C) | Nicotinic receptors do not contain an ion channel. |
| | D) | Nicotinic receptors are closed until ACh molecules bind to the receptor proteins. |
|
|
|
| 40 | |
Acetylcholinesterase is an enzyme located on or immediately outside the |
| | A) | presynaptic membrane. |
| | B) | postsynaptic membrane. |
| | C) | axon terminal cytoplasm. |
| | D) | vesicles released by exocytosis. |
|
|
|
| 41 | |
Which of the following statements about excitatory postsynaptic potentials (EPSPs) is false? |
| | A) | EPSPs are all-or-none events. |
| | B) | EPSPs may result from the opening Na+ gates upon stimulation. |
| | C) | EPSPs at nicotinic ACh synapses are inhibited by the drug curare, but not by tetrodotoxin. |
| | D) | Acetylcholine opens ion gates that produce EPSPS. |
|
|
|
| 42 | |
Curare reduces the size of end plate potentials on the membrane of muscle fibers by |
| | A) | competing with acetylcholine for attachment to the postsynaptic receptor proteins. |
| | B) | blocking the release of acetylcholine from presynaptic vesicles. |
| | C) | enhancing the breakdown of acetylcholine by acetylcholinesterase. |
| | D) | blocking the flow of Na+ through open ion channels. |
|
|
|
| 43 | |
Myasthenia gravis is a disease producing muscle weakness caused by |
| | A) | immune system antibodies that block and destroy acetylcholine receptors. |
| | B) | blocking the release of acetylcholine from presynaptic vesicles. |
| | C) | enhancing the breakdown of acetylcholine by acetylcholinesterase. |
| | D) | blocking the flow of Na+ through open ion channels. |
|
|
|
| 44 | |
The first voltage-regulated gates encountered along the neuron membrane, which initiate the formation of action potentials, are located on the neuron near the |
| | A) | postsynaptic membrane of the dendrite. |
| | B) | cell body. |
| | C) | axon hillock. |
| | D) | axon terminal. |
|
|
|
| 45 | |
All of the following regulatory molecules are neurotransmitters in the chemical family known as monoamines, except |
| | A) | acetylcholine. |
| | B) | epinephrine. |
| | C) | dopamine. |
| | D) | serotonin. |
|
|
|
| 46 | |
Which of the following actions is not normally used to inhibit the stimulatory effects of monoamines released from presynaptic vesicles? |
| | A) | reuptake into the presynaptic neuron ending |
| | B) | enzyme degradation (breakdown) by monoamine oxidase enzymes |
| | C) | blockade of the receptor and inhibition by specific receptor antagonists |
| | D) | enzyme degradation by catecholamine-O-methyltransferase enzymes |
|
|
|
| 47 | |
Activation of protein kinase by cyclic adenosine monophosphate in response to norepinephrine results in |
| | A) | degradation of norepinephrine by converting it into inactive metabolites. |
| | B) | phosphorylation of other proteins that open postsynaptic membrane channels and have other effects in the postsynaptic cell . |
| | C) | activation of phosphodiesterase. |
| | D) | catalyzes the conversion of ADP and phosphate to active ATP. |
|
|
|
| 48 | |
Cocaine stimulates the synapses of specific neurons that release dopamine and other monoamines, by |
| | A) | inhibiting enzyme inactivation of dopamine or monoamines. |
| | B) | blocking the dopamine or monoamine reuptake into the presynaptic axon ending. |
| | C) | mimicking the effects of dopamine or monoamines on the postsynaptic cell. |
| | D) | facilitating the release of dopamine or monoamines from the presynaptic cell terminal. |
|
|
|
| 49 | |
Parkinson's disease is caused by loss of neurons that secrete the neurotransmitter |
| | A) | acetylcholine. |
| | B) | norepinephrine. |
| | C) | serotonin. |
| | D) | dopamine. |
|
|
|
| 50 | |
Drugs known as amphetamines stimulate neural pathways causing mental arousal and peripheral nervous system effects that duplicate sympathetic nerve activation. The neurotransmitter that amphetamines mimic in this way, is |
| | A) | acetylcholine. |
| | B) | norepinephrine. |
| | C) | serotonin. |
| | D) | dopamine. |
|
|
|
| 51 | |
Which of the following neurotransmitters is inhibitory, causing the chloride (Cl-) channels to open in the postsynaptic membrane and forming IPSPs? |
| | A) | glycine |
| | B) | aspartic acid |
| | C) | norepinephrine |
| | D) | glutamic acid |
|
|
|
| 52 | |
_________ is/are lipid-like compound(s) produced by the brain that are believed to act as analgesics. |
| | A) | Carbon monoxide |
| | B) | Neuropeptide Y. |
| | C) | Endorphins. |
| | D) | Endocannabinoids |
|
|
|
| 53 | |
The neurotransmitter that appears to be involved in diseases that affect the motor control of muscles, such as Huntington's chorea, status epilepticus (seizures), and perhaps, severe alterations in mood and emotions, is known as |
| | A) | actylcholine. |
| | B) | norepinephrine. |
| | C) | serotonin. |
| | D) | GABA. |
|
|
|
| 54 | |
Which of the following is not a brain neurotransmitter that may have opioid (pain relieving) properties? |
| | A) | enkaphalin peptides. |
| | B) | dynorphin polypeptides. |
| | C) | ß-endorphins. |
| | D) | catecholamines. |
|
|
|
| 55 | |
Which of the following statements about nitric oxide (NO) is false? |
| | A) | NO acts locally to relax the smooth muscles of blood vessels. |
| | B) | NO is occasionally used by dentists as an anesthetic. |
| | C) | NO acts as a neurotransmitter of certain neurons in both the PNS and CNS. |
| | D) | NO stimulates the production of cyclic guanosine monophosphate (cGMP). |
|
|
|
| 56 | |
EPSPs produced by many different presynaptic fibers converging on a single postsynaptic neuron, causing summation on the postsynaptic dendrites and cell body, best describes |
| | A) | synaptic plasticity. |
| | B) | temporal summation. |
| | C) | synaptic inhibition. |
| | D) | spatial summation. |
|
|
|
| 57 | |
The neural mechanism that may represent a form of "learning" when transmission along frequently used nerve pathways results in improved efficiency of synaptic transmission, is called |
| | A) | long-term potentiation. |
| | B) | synaptic inhibition. |
| | C) | presynaptic inhibition. |
| | D) | synaptic plasticity. |
|
|
|
| 58 | |
Which of the following is not characteristic of presynaptic inhibition? |
| | A) | The axon of a second neuron synapses with the axon (rather than the dendrite) of the original neuron. |
| | B) | The second neuron axon has a direct inhibitory effect on the original neuron axon. |
| | C) | The first neuron is partially depolarized by the release of a neurotransmitter from the second neuron. |
| | D) | Lesser amounts of a neurotransmitter is released by a neuron due to a second neuron that reduces the number of action potentials arriving at the original neuron terminal. |
|
|
|
| 59 | |
The blood-brain barrier is composed of two cells types, endothelial cells and __________. |
| | A) | oligodendrites |
| | B) | microglia |
| | C) | Schwann cells |
| | D) | astrocytes |
|
|
|
| 60 | |
What is the name of the time period during the course of an action potential when no degree of depolarization can initiate another action potential? |
| | A) | relative refractory period |
| | B) | absolute refractory period |
| | C) | overshoot |
| | D) | threshold |
|
|
|
| 61 | |
Along the myelinated sections between nodes in a myelinbated axon, electrical signals are conducted by |
| | A) | active transport. |
| | B) | saltatory conduction. |
| | C) | cable properties. |
| | D) | neurotransmitters. |
|
|
|
| 62 | |
The velocity of an axon potential across an axon will be greatest in which type of axon? |
| | A) | myelinated, thin |
| | B) | myelinated, thick |
| | C) | unmyelinated, thin |
| | D) | unmyelinated, thick |
|
|
|
| 63 | |
When an action potential arrives at the synaptic ending, there is an increase in the _____________ concentration of calcium at the synaptic ending. The increased diffusion of this ion across the cell membrane is produced by the opening of a _______________ gate. |
| | A) | extracellular, voltage-regulated |
| | B) | intracellular, voltage-regulated |
| | C) | extracellular, chemically-regulated |
| | D) | intracellular, chemically-regulated |
|
|
|
| 64 | |
Benzodiazepines have sedative properties because they |
| | A) | keep GABA receptors open longer than normal. |
| | B) | close GABA receptors. |
| | C) | keep GABA receptors open more frequently. |
| | D) | inhibit the reuptake of glutamate. |
|
|
|
| 65 | |
Which glial cells are responsible for myelination of axons in the CNS? |
| | A) | astrocytes |
| | B) | microglia |
| | C) | oligodendrites |
| | D) | Schwann cells |
|
|
.