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1
The central nervous system (CNS) includes the brain and the cranial nerves.
A)True
B)False
2
The nervous system is composed of two principal types of cells - neurons and neuroglia.
A)True
B)False
3
After birth, the neurons do not undergo further division by mitosis, although some neurons can regenerate severed portions or sprout new branches under some conditions.
A)True
B)False
4
The Nissl bodies of the perikaryon contain densely staining areas of active mitochondria.
A)True
B)False
5
A mixed nerve contains both sensory and motor fibers.
A)True
B)False
6
The longer process of a neuron that conducts impulses away from the cell body is called a dendrite.
A)True
B)False
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.
A)True
B)False
8
Association neurons (interneurons) are located entirely within the central nervous system.
A)True
B)False
9
Somatic motor neurons are responsible for both reflex and voluntary control of skeletal muscle.
A)True
B)False
10
The sheaths of Schwann surround all axons in the peripheral nervous system, but not in the central nervous system.
A)True
B)False
11
Gaps of exposed axon between the adjacent Schwann cells for the purpose of producing nerve impulses are called nodes of Ranvier.
A)True
B)False
12
Each Schwann cell can myelinate axons from many neurons.
A)True
B)False
13
Spaces (pores) are found between the endothelial cells lining the capillary wall in the brain. These pores help form the blood-brain barrier.
A)True
B)False
14
Myelin sheaths around the high number of axons in the CNS give this tissue a white color; so is called the white matter of the brain and spinal cord.
A)True
B)False
15
Unlike a Schwann cell, which forms a myelin sheath around only one axon, each oligodendrocyte has extensions like the tentacles of an octopus.
A)True
B)False
16
Experiments suggest that central nervous system axons may neuron nourishing" molecules are present.
A)True
B)False
17
Astrocytes have been shown to be important in the formation of synapses in the developing nervous system.
A)True
B)False
18
Bacterial infection of the brain would stimulate the actions of the microglial cells.
A)True
B)False
19
The tight junctions located between adjacent endothelial cells in brain capillaries that form the blood-brain barrier presents an obstacle to the use of polar drugs in the treatment of many brain diseases, such as Parkinson's disease.
A)True
B)False
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.
A)True
B)False
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.
A)True
B)False
22
The return of the membrane potential toward the resting potential is called hyperpolarization.
A)True
B)False
23
When the inside of the cell becomes more negative due to the inward flow of negative charges, the membrane will be depolarized.
A)True
B)False
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.
A)True
B)False
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+.
A)True
B)False
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.
A)True
B)False
27
Since K+ is positively charged, the diffusion of K+ down its concentration gradient and out of the cell results in hyperpolarization.
A)True
B)False
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.
A)True
B)False
29
The amplitude (height) of an action potential is always the same, resulting in the "all-or-none" law of action potentials.
A)True
B)False
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).
A)True
B)False
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.
A)True
B)False
32
The absolute refractory period occurs before the relative refractory period.
A)True
B)False
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.
A)True
B)False
34
Compared to metal wires, the axon is a very poor electrical conductor.
A)True
B)False
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.
A)True
B)False
36
The high-speed conduction of neural impulses is made possible due to the cable properties of the axon.
A)True
B)False
37
The action potential generated at the end of the axon looks different from that formed at the beginning of the axon.
A)True
B)False
38
Action potentials conducted along thicker, unmyelinated fibers are conducted faster than those along thin, unmyelinated fibers.
A)True
B)False
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) rapid responses of skeletal muscles.
A)True
B)False
40
Saltatory conduction of action potentials is made possible by the interruptions in the myelin sheath along axons, known as nodes of Ranvier.
A)True
B)False
41
A neuron-to-muscle synapse can also be called a myoneural and neuromuscular junction.
A)True
B)False
42
All synaptic transmission is electrical rather than chemical.
A)True
B)False
43
Acetylcholine, discovered by Otto Loewi, was one of the first neurotransmitter chemicals identified and is released from nerve endings to decrease heart rate.
A)True
B)False
44
Gap junctions are characteristic features of smooth and cardiac muscle cells (fibers), brain neurons, and even many embryonic tissues.
A)True
B)False
45
The term terminal boutons refers to the swollen ending of the presynaptic axon terminal.
A)True
B)False
46
Chemically-regulated channels are found in the postsynaptic membrane and open in response to binding of neurotransmitter molecules (ligands) to their postsynaptic receptor proteins.
A)True
B)False
47
Botulinum toxin contains enzymes that prevent the release of neurotransmitter molecules by cleaving and inactivating specific synapsin proteins that are required for exocytosis.
A)True
B)False
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.
A)True
B)False
49
At autonomic nerve endings, the effects of acetylcholine can be either excitatory or inhibitory, depending on the subtype of acetylcholine receptors present in that organ.
A)True
B)False
50
The two major subtypes of acetylcholine receptors are nicotinic and muscarinic, named after the particular toxin that bind and interact with each subtype of receptor.
A)True
B)False
51
Acetylcholie is transported into the postsynaptic cell cytoplasm, where it produces its effects, such as opening ion channels.
A)True
B)False
52
When neurotransmitters bind to the appropriate receptor on the postsynaptic cell the direct response is not an action potential, but rather ae graded potentials such as an EPSP or an IPSP.
A)True
B)False
53
Acetylcholinesterase is an enzyme found in the presynaptic cell that degrades acetylcholine.
A)True
B)False
54
The bond between the ligand, actylcholine and its receptor protein is relatively weak bond.
A)True
B)False
55
Unlike action potentials, excitatory postsynaptic potentials (EPSPs) have no threshold potential, can be summed, and have no refractory period.
A)True
B)False
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.
A)True
B)False
57
Exposure to nerve gas would lead to spastic paralysis.
A)True
B)False
58
Somatic motor neurons only make synapses with skeletal muscle fibers, resulting in postsynaptic depolarizations called end plate potentials.
A)True
B)False
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 dopamine.
A)True
B)False
60
Some antidepressant drugs act to block the reuptake of serotonin.
A)True
B)False
61
Epinephrine is also known as adrenalin, a hormone secreted by the adrenal cortex.
A)True
B)False
62
As a neurotransmitter, norepinephrine binds to a G-coupled receptor.
A)True
B)False
63
Of the catecholamines, dopamine acts only as a neurotransmitter molecule and not as a hormone.
A)True
B)False
64
Drugs that inhibit the action of the enzymes that breakdown catecholamines, ultimately end up promoting the effects of monoamine neurotransmitter action on the postsynaptic membrane.
A)True
B)False
65
Instead of opening ionic channels directly in the postsynaptic membrane, monoamine neurotransmitters act through a second messenger molecule, such as cyclic adenosine monophosphate.
A)True
B)False
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.
A)True
B)False
67
Parasympathetic neurons of the peripheral nervous system use norepinephrine as the neurotransmitter at their synapses with smooth muscles, cardiac muscle, and glands.
A)True
B)False
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.
A)True
B)False
69
GABA (gamma-amino butyric acid) and glycine are excitatory neurotransmitters in the central nervous system, depolarizing the postsynaptic membrane and forming EPSPs.
A)True
B)False
70
Most inhibitory neurotransmitters act to hyperpolarize the postsynaptic membranes of their target cells, producing inhibitory postsynaptic potentials (IPSPs).
A)True
B)False
71
Animals poisoned with strychnine die from asphyxiation because their glycine receptor proteins are specifically blocked and they are unable to relax the diaphragm muscle (spastic paralysis).
A)True
B)False
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.
A)True
B)False
73
Synaptic plasticity is believed to be due in part to the release of neuromodulators and neurotransmitters from the same presynaptic cell.
A)True
B)False
74
Excessive release of glutamate may produce excitotoxicity.
A)True
B)False
75
The family of polypeptides produced by the brain and pituitary gland called opioids include β-endorphin, the enkephalins, and the neurotransmitter, dynorphin.
A)True
B)False
76
Spacial summation requires the actions of two synapses.
A)True
B)False





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