Chapter 48 & 49: Nervous System Flashcards
1
Q
Nerve Net
A
A weblike system of neurons, charac- teristic of radially symmetrical animals, such as hydras.
2
Q
Nerves
A
A fiber composed primarily of the bundled axons of PNS neurons.
3
Q
Reflexes
A
An automatic reaction to a stimulus, mediated by the spinal cord or lower brain.
4
Q
Central Canal
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The narrow cavity in the center of the spinal cord that is continuous with the fluid-filled ventricles of the brain.
5
Q
Ventricle
A
A space in the vertebrate brain, filled with cerebrospinal fluid.
6
Q
Cerebrospinal Fluid
A
Blood-derived fluid that surrounds, protects against infection, nourishes, and cushions the brain and spinal cord.
7
Q
Gray Matter
A
Regions of dendrites and clustered neuron cell bodies within the CNS.
8
Q
White Matter
A
Tracts of axons within the CNS.
9
Q
Motor System
A
An efferent branch of the vertebrate peripheral nervous system composed of motor neurons that carry signals to skeletal muscles in response to external stimuli.
10
Q
Autonomic Nervous System (ANS)
A
An efferent branch of the vertebrate peripheral nervous system that regulates the internal environment; consists of the sympathetic, parasympathetic, and enteric divisions.
11
Q
Sympathetic Division
A
One of three divisions of the autonomic nervous system; generally increases energy expenditure and prepares the body for action.
12
Q
Parasympathetic Division
A
One of three divi- sions of the autonomic nervous system; gener- ally enhances body activities that gain and conserve energy, such as digestion and reduced heart rate.
13
Q
Enteric Division
A
One of three divisions of the autonomic nervous system; consists of networks of neurons in the digestive tract, pancreas, and gallbladder; normally regulated by the sympathetic and parasympathetic divisions of the autonomic nervous system.
14
Q
Reticular Formation
A
A diffuse network of neurons in the core of the brain- stem that filters information traveling to the cerebral cortex.
15
Q
Biological Clock
A
An internal timekeeper that controls an organism’s biological rhythms. The biological clock marks time with or without environmental cues but often requires signals from the environment to remain tuned to an appropriate period. See also circadian rhythm.
16
Q
Suprachiasmatic Nucleus (SCN)
A
A group of neurons in the hypothalamus of mammals that functions as a biological clock.
17
Q
Amygdala
A
A structure in the temporal lobe of the vertebrate brain that has a major role in the processing of emotions.
18
Q
Lateralization
A
Segregation of functions in the cortex of the left and right cerebral hemispheres.
19
Q
Neural Plasticity
A
The capacity of a nervous system to change with experience.
20
Q
Short-Term Memory
A
The ability to hold information, anticipations, or goals for a time and then release them if they become irrelevant.
21
Q
Long-Term Memory
A
The ability to hold, associate, and recall information over one’s lifetime.
22
Q
Long-Term Potential
A
An enhanced responsiveness to an action potential (nerve signal) by a receiving neuron.
23
Q
Schizophrenia
A
A severe mental disturbance characterized by psychotic episodes in which patients have a distorted perception of reality.
24
Q
Major Depressive Disorder
A
A mood disorder characterized by feelings of sadness, lack of self-worth, emptiness, or loss of interest in nearly all things.
25
Bipolar Disorder
A depressive mental illness characterized by swings of mood from high to low; also called manic-depressive disorder.
26
Alzheimer's Disease
An age-related dementia (mental deterioration) char- acterized by confusion and memory loss.
27
Parkinsons Disease
A progressive brain disease characterized by difficulty in initiating move- ments, slowness of movement, and rigidity.
28
Corpus Callosum
The thick band of nerve fibers that connects the right and left cerebral hemispheres in mammals, enabling the hemispheres to process information together.
29
Pons
A portion of the brain that participates in certain automatic, homeostatic functions, such as regulating the breathing centers in the medulla.
30
Medulla Oblangata
The lowest part of the vertebrate brain, commonly called the medulla; a swelling of the hindbrain anterior to the spinal cord that controls autonomic, homeostatic functions, including breathing, heart and blood vessel activity, swallowing, digestion, and vomiting.
31
Reticular Formation
A diffuse network of neurons in the core of the brain- stem that filters information traveling to the cerebral cortex.
32
Brainstem
A collection of structures in the verte- brate brain, including the midbrain, the pons, and the medulla oblongata; functions in homeostasis, coordination of movement, and
conduction of information to higher brain
centers.
33
Cerebellum
Part of the verte- brate hindbrain located dorsally; functions in unconscious coordination of movement and balance.
34
Thalamus
An integrating center of the vertebrate forebrain. Neurons with cell bodies in the thalamus relay neural input to specific areas in the cerebral cortex and regulate what information goes to the cerebral cortex.
35
Cerebrum
The dorsal portion of the vertebrate forebrain, composed of right and left hemispheres; the integrating center for memory, learning, emotions, and other highly complex fu
36
Hypothalamus
The ventral part of the vertebrate forebrain; functions in maintaining homeostasis, especially in coordinating the endocrine and nervous systems; secretes hormones of the posterior pituitary and releasing factors that regulate the anterior pituitary.
37
Cerebral Cortex
The surface of the cerebrum; the largest and most complex part of the mammalian brain, containing nerve cell
bodies of the cerebrum; the part of the verte-
brate brain most changed through evolution.
38
Cerebral Hemisphere
The right or left side of the cerebrum.
39
What are electrical synapses and how are they different from chemical synapses?
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40
How is Calcium involved in the chemical synapse?
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41
What are ligand-gated ion channels?
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42
Differentiate between excitatory and inhibitory post-synaptic potential.
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43
Explain the principal of summation.
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44
What is the euro-muscular junction?
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45
What are some examples of neurotransmitters? Explain how the work.
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46
How might pharmaceutical drugs mimic these neurotransmitters?
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47
How does Botox or other neurotoxins affect neurotransmitters?
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48
How do gases such as NO and CO get used by the nervous and endocrine system?
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49
Describe the basic pathway of information flow through neutrons that causes you to turn your head when someone calls your name.
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50
How might increased branching of an axon help coordinate responses to signals communicated by the nervous system?
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51
Consider how communication occurs in a colony of bacteria. In what general ways is that communication similar to and different from transmission of nerve impulse by a neuron?
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52
Under what circumstances could ions flow through ion channels from regions of low ion concentrated to regions of high ion concentration?
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53
Suppose a cell's membrane potential shifts from -70mv to -50mv. What changes in the cell's permeability to K+ and Na+ could cause such a shift?
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54
Oubain, a plant substance used in some cultures of poison hunting arrows, disables the Na-K pump. What changes in the resign potential would you expect to see if you treated a neuron with oubain? Explain.
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55
What is Equilibrium potential? How is it calculated?
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56
In multiple sclerosis, myelin sheaths harden and deteriorate. How would this affect nervous system function?
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57
Suppose a mutation caused gated sodium channels to remain inactivated longer after an action potential. How would this affect the frequency at which action potentials could be generated? Explain.
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58
How is it possible for a particular neurotransmitter to produce opposite effects in different tissues?
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59
What is the difference between Excitatory Post-Synaptic Potentials (EPSPs) and Inhibitory Post Synaptic Potentials (IPSPs)?
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60
Organophosphate pesticides work by inhibiting acetylcholinesterase, the enzyme that breaks down the neurotransmitter acetylcholine. Explain how these toxins would affect EPSPs produced by acetyl choline.
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61
What do the neurotransmitters Glutamate and GABA do in the CNS?
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62
If a drug mimicked the activity of GABA in the CNS, what general effect on behaviour might you expect? Explain.
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63
Neuron
A nerve cell; the fundamental unit of the nervous system, having structure and properties that allow it to conduct signals by taking advantage of the electrical charge across its plasma membrane.
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Brain
Organ of the central nervous system where information is processed and integrated.
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Ganglia
Clusters (functional groups) of nerve cell bodies in a centralized nervous system.
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Central Nervous System
The portion of the nervous system where signal integration occurs; in vertebrate animals, the brain and spinal cord.
67
Peripheral Nervous System
The sensory and motor neurons that connect to the central nervous system.
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Sensory Neurons
A nerve cell that receives infor- mation from the internal or external environ- ment and transmits signals to the central nervous system.
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Interneurons
An association neuron; a nerve cell within the central nervous system that forms synapses with sensory and/or motor neurons and integrates sensory input and motor output.
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Motor Neurons
A nerve cell that transmits signals from the brain or spinal cord to muscles or glands.
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Cell Body
The part of a neuron that houses the nucleus and most other organelles.
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Dendrite
One of usually numerous, short, highly branched extensions of a neuron that receive signals from other neurons.
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Axon
A typically long extension, or process, of a neuron that carries nerve impulses away from the cell body toward target cells.
74
Synapse
The junction where a neuron communicates with another cell across a nar- row gap via a neurotransmitter or an electrical coupling.
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Neurotransmitter
A molecule that is released from the synaptic terminal of a neuron at a chemical synapse, diffuses across the synaptic cleft, and binds to the postsynaptic cell, triggering a response.
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Glia Cells (Glia)
Cells of the nervous system that support, regulate, and augment the functions of neurons.
77
Membrane Potential
The difference in electrical charge (voltage) across a cell’s plasma membrane due to the differential distribution of ions. Membrane potential affects the activity of excitable cells and the transmembrane movement of all charged substances.
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Resting Potential
The membrane potential char- acteristic of a nonconducting excitable cell, with the inside of the cell more negative than the outside.
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Ion Channel
A transmembrane protein channel that allows a specific ion to diffuse across the membrane down its concentration or electrochemical gradient.
80
Equilibrium Potential (Eion)
The magnitude of a cell’s membrane voltage at equilibrium;
| calculated using the Nernst equation.
81
Gated Ion Channels
A gated channel for a specific ion. The opening or closing of such channels may alter a cell’s membrane potential.
82
Hyperpolarization
A change in a cell’s membrane potential such that the inside of the membrane becomes more negative relative to the outside. Hyperpolarization reduces the chance
that a neuron will transmit a nerve impulse.
83
Depolarization
A change in a cell’s membrane potential such that the inside of the mem- brane is made less negative relative to the outside. For example, a neuron membrane is depolarized if a stimulus decreases its voltage from the resting potential of 70 mV in the direction of zero voltage.
84
Graded Potential
In a neuron, a shift in the membrane potential that has an amplitude proportional to signal strength and that decays as it spreads.
85
Action Potential
An electrical signal that propa- gates (travels) along the membrane of a neuron or other excitable cell as a nongraded (all-or- none) depolarization.
86
Voltage-Gated Ion Channels
A specialized ion channel that opens or closes in response to changes in membrane potential.
87
Threshold
The potential that an excitable cell membrane must reach for an action potential to be initiated.
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Refractory Period
The short time immediately after an action potential in which the neuron cannot respond to another stimulus, owing to the inactivation of voltage-gated sodium channels.
89
Myelin Sheath
Wrapped around the axon of a neuron, an insulating coat of cell membranes from Schwann cells or oligoden- drocytes. It is interrupted by nodes of Ranvier, where action potentials are generated.
90
Oligodendrocytes
A type of glial cell that forms insulating myelin sheaths around the axons of neurons in the central nervous system.
91
Schwann Cells
A type of glial cell that forms insulating myelin sheaths around the axons of neurons in the peripheral nervous system.
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Node of Ranvier
Gap in the myelin sheath of certain axons where an action poten- tial may be generated. In saltatory conduction, an action potential is regenerated at each node, appearing to “jump” along the axon from node to node.
93
Saltatory Conduction
Rapid transmission of a nerve impulse along an axon, resulting from the action potential jumping from one node of Ranvier to another, skipping the myelin-sheathed regions of membrane.
94
Ligan-Gated Ion Channels
A transmembrane
protein containing a pore that opens or closes as it changes shape in response to a signaling
molecule (ligand), allowing or blocking the flow of specific ions; also called an ionotropic receptor.
95
Temporal Summation
A phenomenon of neural integration in which the membrane potential of the postsynaptic cell in a chemical synapse is determined by the combined effect of EPSPs or IPSPs produced in rapid succession.
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Spatial Summation
A phenomenon of neural integration in which the membrane potential of the postsynaptic cell is determined by the combined effect of EPSPs or IPSPs produced nearly simultaneously by different synapses.
97
Acetylcholine
One of the most common neurotransmitters; functions by binding to receptors and altering the perme- ability of the postsynaptic membrane to specific ions, either depolarizing or hyperpolarizing the membrane.
98
Glutamate
An amino acid that functions as a neurotransmitter in the central nervous system.
99
Gamma-Aminobutyric Acid (GABA)
An amino acid that functions as a CNS neurotransmitter in the central nervous system of vertebrates.
100
Biogenic Amines
A neurotransmitter derived from an amino acid.
101
Norepinephrine
A catecholamine that is chemically and functionally similar to epinephrine and acts as a hormone or neurotransmitter; also known as noradrenaline.
102
Dopamine
A neurotransmitter that is a catecholamine, like epinephrine and norepinephrine.
103
Serotonin
A neurotransmitter, synthesized from the amino acid tryptophan, that functions in the central nervous system.
set point In homeostasis in animals, a value
104
Neuropeptide
A relatively short chain of amino acids that serves as a neurotransmitter.
105
Endorphin
Any of several hormones produced in the brain and anterior pituitary that inhibit pain perception.
106
Inhibitory Postsynaptic Potential (IPSP)
An electrical change (usually hyperpolarization) in the membrane of a postsynaptic neuron caused by the binding of an inhibitory neurotransmitter from a presynaptic cell to a post-synaptic receptor; makes it more difficult for a postsynaptic neuron to generate an action potential.
107
Excitatory Postsynaptic Potential (EPSP)
An electrical change (depolarization) in the membrane of a postsynaptic cell caused by the binding of an excitatory neurotransmitter from a presynaptic cell to a postsynaptic receptor; makes it more likely for a postsynaptic cell to generate an action potential.
