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1 | |
The central nervous system (CNS) includes the spinal nerves arising from the spinal cord(p. 150) |
| | A) | True |
| | B) | False |
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2 | |
The nervous system is composed of two principal types of cells--neurons and neuroglia. (p. 150) |
| | A) | True |
| | B) | False |
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3 | |
Neurons cannot divide by mitosis, although some neurons can regenerate severed portions or sprout new branches under some conditions. (p. 150) |
| | A) | True |
| | B) | False |
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4 | |
The Nissl bodies of the perikaryon contain densely staining areas of active mitochondria. (p. 151) |
| | A) | True |
| | B) | False |
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5 | |
In the brain, neurons outnumber neuroglia, or glial cells five to one. (p. 150) |
| | A) | True |
| | B) | False |
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6 | |
The longer process of a neuron that conducts impulses away from the cell body is the dendrite.(p. 152) |
| | A) | True |
| | B) | False |
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7 | |
Orthograde (forward flow)and retrograde (reverse flow) transport in neurons is characteristic of the more rapid form of molecular movement in the neuron called axonal transport. (p. 151) |
| | A) | True |
| | B) | False |
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8 | |
Association neurons (interneurons) are located entirely within the central nervous system (CNS).(p. 152) |
| | A) | True |
| | B) | False |
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9 | |
Autonomic motor neurons are responsible for both reflex and voluntary control of skeletal muscle. (p.152) |
| | A) | True |
| | B) | False |
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10 | |
All axons in the CNS, but not in the peripheral nervous system (PNS), are surrounded by the sheaths of Schwann. (p. 153) |
| | A) | True |
| | B) | False |
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11 | |
Gaps of exposed axon between the adjacent Schwann cells for the purpose of producing nerve impulses are called nodes of Ranvier. (p. 154) |
| | A) | True |
| | B) | False |
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12 | |
Oligodendrocytes are able to myelinate multiple axons. (p. 154) |
| | A) | True |
| | B) | False |
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13 | |
Spaces (pores) are found between the endothelial cells lining the capillary wall in the brain. These pores help form the blood-brain barrier. (p. 157) |
| | A) | True |
| | B) | False |
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14 | |
Myelin sheaths around the high number of axons in the CNS give this tissue a gray color; so is called the gray matter region of the brain and spinal cord. (p. 154) |
| | A) | True |
| | B) | False |
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15 | |
Unlike a Schwann cell, which forms a myelin sheath around only one axon, each oligodendrocyte has extensions like the tentacles of an octopus. (p. 154) |
| | A) | True |
| | B) | False |
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16 | |
Experiments suggest that central nervous system axons may regenerate if chemicals such as nerve growth factor (NGF) and other neurotrophins ("neuron nourishing" molecules) are present. (p. 157) |
| | A) | True |
| | B) | False |
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17 | |
The most abundant of the neurological cells in the CNS, constituting up to 90% of the nervous tissue in some areas of the brain are the oligodendrocytes. (p. 157) |
| | A) | True |
| | B) | False |
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18 | |
Astrocytes can take up glutamic acid and gamma-aminobutyric acid (GABA) neurotransmitters from the extracellular fluid (ECF), break them down, and produce glutamine molecules that are released for general distribution to other neurons. (p. 157) |
| | A) | True |
| | B) | False |
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19 | |
The blood-brain barrier or tight junctions located between adjacent endothelial cells in brain capillaries presents an obstacle to the use of certain drugs in the treatment of many brain diseases, such as Parkinson's disease.(p. 158) |
| | A) | True |
| | B) | False |
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20 | |
Although all cells have a membrane potential, only muscle fibers, neurons, and a few other cell types are able to alter their membrane potential in response to stimulation. (p. 158) |
| | A) | True |
| | B) | False |
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21 | |
The instrument that displays images of the upward and downward changes in the membrane potential on a cathode-ray fluorescent screen is called a voltmeter. (p. 158) |
| | A) | True |
| | B) | False |
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22 | |
The return of the membrane potential toward the resting potential is called hyperpolarization. (p. 159) |
| | A) | True |
| | B) | False |
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23 | |
When the inside of the cell becomes more negative due to the inflow of negative charges, the resting membrane potential will deflect downward, hyperpolarizing the membrane. (p. 159) |
| | A) | True |
| | B) | False |
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24 | |
During depolarization, that potential at which the Na+ gates open causing a sudden and very rapid change in the membrane potential as Na+ ions diffuse down their concentration gradient, is known as the threshold potential. (p. 160) |
| | A) | True |
| | B) | False |
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25 | |
During neuron stimulation, a fraction of a second after the Na+ gates open, they close again. Meanwhile, the resulting depolarization causes the K+ gates to open, allowing the efflux (outward flow) of K+. (p. 160) |
| | A) | True |
| | B) | False |
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26 | |
A negative feedback loop is created as the rate of Na+ entry increases as the rate of membrane depolarization increases in an explosive fashion. (p. 160) |
| | A) | True |
| | B) | False |
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27 | |
Since K+ is positively charged, the diffusion of K+ down its concentration gradient and into the cell results in hyperpolarization. (p. 161) |
| | A) | True |
| | B) | False |
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28 | |
A neuron poisoned with cyanide so that no ATP can be made will still produce action potentials for a period of time since active transport of ions is not directly involved in impulse conduction. (p. 160) |
| | A) | True |
| | B) | False |
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29 | |
The amplitude of an action potential (or spike potential) refers to its height and is always the same, resulting in the "all-or-none" law of action potentials. (p. 161) |
| | A) | True |
| | B) | False |
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30 | |
The greater the strength of the stimulus the greater the amplitude of action potentials; therefore the code for stimulus strength is amplitude modulated (AM), not frequency modulated (FM). (p. 162) |
| | A) | True |
| | B) | False |
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31 | |
A low-intensity stimulus to a collection of axons (or a nerve) will only activate those few fibers in the group with lower thresholds, whereas a high-intensity stimulus can activate many more fibers including those with higher thresholds. (p. 162) |
| | A) | True |
| | B) | False |
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32 | |
The relative refractory period occurs before the absolute refractory period.(p. 162) |
| | A) | True |
| | B) | False |
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33 | |
The term cable properties of neurons refers to the ability of a neuron to transmit charges through its cytoplasm; a property that is quite poor due to the cell's high internal resistance. (p. 162) |
| | A) | True |
| | B) | False |
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34 | |
Compared to metal wires, the axon is a very poor electrical conductor. (p. 162) |
| | A) | True |
| | B) | False |
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35 | |
Every patch of membrane in an unmyelinated axon contains Na+ and K+ gates that must regenerate or remake a separate, completely new action potential that will move along the axon, usually in a direction away from the cell body. (p. 163) |
| | A) | True |
| | B) | False |
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36 | |
The high-speed conduction of neural impulses is made possible due to the cable properties of the axon. (p. 163) |
| | A) | True |
| | B) | False |
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37 | |
The action potential generated at the end of the axon looks different from that formed at the beginning of the axon. (p. 163) |
| | A) | True |
| | B) | False |
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38 | |
Action potentials conducted along thicker, unmyelinated fibers are conducted faster than those along thin, unmyelinated fibers; and are substantially faster if the axon is myelinated. (p. 163) |
| | A) | True |
| | B) | False |
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39 | |
As opposed to thin, unmyelinated nerve fibers, thick myelinated fibers would be expected to mediate (to come in the middle of or to control) slow responses in the viscera (internal organs and smooth muscle).(p. 163) |
| | A) | True |
| | B) | False |
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40 | |
Saltatory conduction of action potentials is made possible by the interruptions in the myelin sheath along axons, known as nodes of Ranvier. (p. 163) |
| | A) | True |
| | B) | False |
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41 | |
Myoneural and neuromuscular junctions mean the same thing - that is they refer to a neuron-to-muscle synapse. (p. 164) |
| | A) | True |
| | B) | False |
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42 | |
All synaptic transmission is electrical rather than chemical. (p. 164) |
| | A) | True |
| | B) | False |
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43 | |
Acetylcholine (ACh), discovered by Otto Loewi, was one of the first neurotransmitter chemicals identified and is released from nerve endings in the heart, ACh slowed the heart rate. (p. 164) |
| | A) | True |
| | B) | False |
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44 | |
Gap junctions are characteristic features of smooth and cardiac muscle cells (fibers), brain neurons, and even many embryonic tissues. (p. 165) |
| | A) | True |
| | B) | False |
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45 | |
The synaptic cleft refers to the swollen ending of the presynaptic axon terminal. (p. 166) |
| | A) | True |
| | B) | False |
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46 | |
Voltage-regulated channels are found in the postsynaptic membrane and open in response to binding of neurotransmitter molecules (ligands) to their postsynaptic receptor proteins. (p. 166) |
| | A) | True |
| | B) | False |
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47 | |
The deadly botulinum toxin contains enzymes that prevent the release of neurotransmitter molecules by cleaving and inactivating specific synapsin proteins that are required for exocytosis. (p. 166) |
| | A) | True |
| | B) | False |
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48 | |
Depolarization of the postsynaptic membrane by specific neurotransmitter chemicals (ligands) results in an EPSP, whereas hyperpolarization of the postsynaptic membrane results in an IPSP. (p. 167) |
| | A) | True |
| | B) | False |
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49 | |
At autonomic nerve endings, the effects of acetylcholine (ACh) can be either excitatory or inhibitory, depending on the subtype of ACh receptors present in that organ. (p. 168) |
| | A) | True |
| | B) | False |
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50 | |
The two major subtypes of acetylcholine receptors are nicotinic and muscarinic, named after the particular toxins that bind and interact with each subtype of receptor. (p. 168) |
| | A) | True |
| | B) | False |
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51 | |
ACh is transported into the postsynaptic cell cytoplasm, where it produces its effects, such as opening ion channels. (p. 169) |
| | A) | True |
| | B) | False |
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52 | |
Neurotransmitter ligands operating chemically regulated gates, do not directly result in action potentials, but rather produce graded potentials such as EPSPs and IPSPs first. (p. 170) |
| | A) | True |
| | B) | False |
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53 | |
Acetylcholinesterase (AChE) is an enzyme on the surface of the postsynaptic membrane that inactivates ACh, thus removing the ligand from the synaptic cleft and interrupting the electrochemical conduction of the nerve impulse. (p. 172) |
| | A) | True |
| | B) | False |
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54 | |
The bond between the ligand, ACh and its receptor protein is an exceptionally strong and lasting bond.(p. 169) |
| | A) | True |
| | B) | False |
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55 | |
Unlike action potentials, excitatory postsynaptic potentials (EPSPs) have no threshold potential, cannot be summed, and have no refractory period. (p. 170) |
| | A) | True |
| | B) | False |
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56 | |
Curare , a drug first used on poison darts by South American Indians, interrupts neuromuscular transmission at the synapse and thereby results in a spastic (causes muscles to spasm, or tighten) form of paralysis. (p. 173) |
| | A) | True |
| | B) | False |
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57 | |
If the strength of the stimulus and the subsequent depolarization of a neuron is adequate, EPSPs will reach the threshold potential and become action potentials at the initial segment of the axon. (p. 174) |
| | A) | True |
| | B) | False |
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58 | |
Somatic motor neurons only make synapses with skeletal muscle fibers, resulting in postsynaptic depolarizations called end plate potentials. (p. 172) |
| | A) | True |
| | B) | False |
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59 | |
The most common cause of senile dementia, Alzheimer's disease, is thought to be caused by a loss of CNS neurons that release the neurotransmitter called serotonin. (p. 174) |
| | A) | True |
| | B) | False |
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60 | |
Serotonin is derived from the amino acid, L-tryptophan. (p. 174) |
| | A) | True |
| | B) | False |
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61 | |
Epinephrine is also known as adrenalin, a hormone secreted by the adrenal cortex. (p. 174) |
| | A) | True |
| | B) | False |
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62 | |
Epinephrine (adrenaline) is both a hormone and a neurotransmitter molecule. (p. 174) |
| | A) | True |
| | B) | False |
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63 | |
Dopamine is only a neurotransmitter molecule and not a hormone. (p. 174) |
| | A) | True |
| | B) | False |
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64 | |
Drugs that inhibit the action of the specific neurotransmitter degrading enzymes MAO (and COMT), ultimately end up promoting the effects of monoamine neurotransmitter action on the postsynaptic membrane. (p. 174) |
| | A) | True |
| | B) | False |
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65 | |
Instead of opening ionic channels directly in the postsynaptic membrane, monoamine neurotransmitters act through a second messenger molecule, such as cyclic adenosine monophosphate (cAMP). (p. 175) |
| | A) | True |
| | B) | False |
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66 | |
Schizophrenia may be caused, in part, by the mesolimbic dopaminergic pathways in the brain secreting too much dopamine or by the presence of increased numbers of D2 dopamine receptors in the forebrain. (p. 177) |
| | A) | True |
| | B) | False |
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67 | |
Sympathetic neurons of the peripheral nervous system (PNS) use norepinephrine as the neurotransmitter at their synapses with smooth muscles, cardiac muscle, and glands. (p. 177) |
| | A) | True |
| | B) | False |
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68 | |
Certain amino acids (such as glycine) act as excitatory neurotransmitters in the CNS by forming EPSPs, while others (such as glutamic acid) inhibit CNS neurons by producing IPSPs. (p. 178) |
| | A) | True |
| | B) | False |
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69 | |
GABA (gamma-amino butyric acid) and glycine are excitatory neurotransmitters in the central nervous system, depolarizing the postsynaptic membrane and forming EPSPs. (p. 178) |
| | A) | True |
| | B) | False |
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70 | |
Most inhibitory neurotransmitters act to hyperpolarize the postsynaptic membranes of their target cells, producing inhibitory postsynaptic potentials (IPSPs). (p. 178) |
| | A) | True |
| | B) | False |
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71 | |
Animals poisoned with curare die from asphyxiation because their glycine receptor proteins are specifically blocked and they are unable to relax the diaphragm muscle (spastic paralysis). (p. 178) |
| | A) | True |
| | B) | False |
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72 | |
Interestingly, many polypeptides that function as hormones secreted by the small intestine and other endocrine glands, can also be made and serve as neurotransmitters in the brain. (p. 178) |
| | A) | True |
| | B) | False |
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73 | |
It has been suggested that some neurons in both the PNS and CNS produce not only a traditional neurotransmitter (ACh or catecholamine) but a polypeptide neuromodulator as well. (p. 178) |
| | A) | True |
| | B) | False |
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74 | |
Naloxone is a drug that mimics (imitates) the analgesic (pain-relieving) action of the opioids, endogenous opium-like compounds produced by certain neurons of the brain. (p. 179) |
| | A) | True |
| | B) | False |
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75 | |
The family of polypeptides produced by the brain and pituitary gland called opioids include β-endorphin, the enkephalins, and the neurotransmitter, dynorphin. (p. 178) |
| | A) | True |
| | B) | False |
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2002 McGraw-Hill Higher Education