Chapter 2: Structure and Function of the Nervous System Flashcards
(134 cards)
1
Q
Embryonic stem cells destined to form the nervous system become two primary types: […]
A
neurons and glial cells (supporting cells)
2
Q
Glial cells provide (3)…
A
metabolic support, protection, and insulation for neurons
3
Q
Sensory neurons are sensitive to […].
A
environmental stimuli
4
Q
Interneurons consist of…
A
nerve cells within the brain and spinal cord
5
Q
Interneurons form complex interacting neural circuits and are responsible for (5)…
A
- conscious sensation
- recognition
- memory
- decision making
- cognition
6
Q
Motor neurons direct a […] appropriate for the situation.
A
biobehavioral response
7
Q
Neurons have what three major external features?
A
- soma
- dendrites
- axon
8
Q
Neurons are enclosed by a […] and are filled with salty, gelatinous fluid– […].
A
semipermeable membrane; cytoplasm
9
Q
T/F: Neurons have mitochondria.
A
true; they contain a lot because of the energy (ATP) requirement
10
Q
Synapse:
A
gap between dendrites and the soma
11
Q
Convergence:
A
when a neuron receives and integrates a vast amount of information from many cells
12
Q
Divergence:
A
when integrated information is transmitted to a few neurons or to thousands of other neurons
13
Q
Dendrites are usually covered with short […] this dramatically increases the receiving […].
A
dendritic spines; surface area
14
Q
T/F: Dendrites and their spines exhibit constant modification.
A
true due to new associations with external interactions
15
Q
How do the dendrites in someone who is intellectually impaired appear?
A
smaller and immature
16
Q
Describe the appearance of dendrites/dendritic spines of someone who has schizophrenia:
A
dendritic size is normal; dendritic spine density is reduced
*particularly in the prefrontal cortex
17
Q
Axons transmit information that is generated by the […].
A
axon hillock
18
Q
Axon collaterals:
A
branching of neuron ends to influence many more cells
19
Q
At the end of axons, there are small enlargements called […] which are located near the […] or […] of other cells.
A
terminal buttons; dendrites; somas
20
Q
Terminal buttons are also called:
A
axon terminals or boutons
21
Q
What is contained in terminal buttons?
A
synaptic vesicles of neurochemicals called neurotransmitters
22
Q
How is myelin created?
A
concentric layers of glial cells
23
Q
What are the two types of glial cells that create myelin sheath?
A
- Schwann cells
2. oligodendroglia cells
24
Q
Schwann cells myelinate […] that serves […], organs, and […].
A
peripheral nerves; muscles; glands
25
Nodes of Ranvier:
bare spots along the axon
26
The thicker the myelin...
the quicker the conduction
27
How does myelination save energy?
reducing the effort required to restore the neuron to its resting state after transmission of the electrical signal
28
MS is an [...] disease in which the immune system attacks a [...] in the [...] produced by [...] only.
autoimmune; protein; myelin; oligodendrocytes
29
MS symptoms:
fatigue, numbness, poor coordination/balance, vision problems, bladder, bowel, and sexual dysfunction, cognitive function, and depression
30
The cell body is responsible for the [...] of the neuron.
metabolic care
31
One of the most important functions of the soma is the synthesis of [...] which are needed throughout the cell for [...] and [...].
proteins; growth; maintenance
32
What are the proteins included in the soma's synthesis?
1. enzymes
2. receptors
3. components of the cell membrane
33
Chromosomes:
long strands of DNA
34
Genes:
small portions of chromosomes that code for the manufacture of a specific protein
35
Transcription factors are [...] that direct [...].
nuclear proteins; protein production
36
Where do transcription factors bind?
promoter region
37
DNA methylation:
attachment of methyl group to a gene that causes a decrease in expression
38
Epigenetic modification. Is this pre or postnatal?
both; modifications can be created and passed on to future generations depending on the external conditions
39
What are some of the external conditions that can cause epigenetic modifications?
1. stress
2. abuse
3. starvation/overeating
4. environmental toxins
etc
40
Explain epigenetic modifications a child could experience if they're overeating.
the child will undergo modifications that over-expresses the genes for obesity and under-expresses those for longevity
41
T/F: Maternal experiences influence the fetus.
true
42
T/F: Environmental events occurring before conception can also impact the health/behavior of offspring.
true
a stressed parent before conception can contribute to mental and physical difficulties of the offspring
43
Axoplasmic transport:
transportation of proteins produced in the soma of neurons
44
What does axoplasmic depend on?
cytoskeleton structure
45
Cytoskeleton: a matrix composed of [...]. These include [...] and [...] that form a mesh-like mass that provides shape of the cell.
tubular structures; microtubules; neurofilaments
46
Microtubules run [...] down the axon. It provides a [...] along which small packets of newly synthesized [...] are carried by specialized [...].
longitudinally; stationary track; proteins; motor proteins
47
Newly synthesized proteins are packaged in the [...] and transported in an [...] toward the axon terminals.
soma; anterograde direction
48
Abnormalities of the cytoskeleton constitute one of several pathological features of the brain in people with...
Alzheimer's disease
49
Neurofibrillary tangles:
found in people who have Alzheimer's
hyperphosphorylation causes tau to separate from the microtubules and leads to entanglement of the usually parallel tubules
50
Neurofibrillary tangles evidently lead to the microtubules becoming...
disintegrated and destroys the material transport system which stops neuron communication
51
Because the membrane is not [...] to charged molecules, special devices are needed to move molecules such as [...], [...], and metabolic products across the membrane.
readily permeable; amino acids; glucose
52
Special devices to move molecules (AA; GLU; metabolites) are...
transporter proteins and charged particles/ion channels
53
Ion channels are [...] molecules that penetrate through the cell membrane and have a [...] through which ions pass.
protein; water-filled pore
54
List the 3 ways that ion channels allow passage.
1. ligand binds to receptor on the channel
2. voltage gate opened due to electrical potential across the membrane near the channel is altered
3. modification of a channel by a secondary messenger (phosphate group)
55
Ion channel important characteristics:
1. relatively specific for particular ions
| 2. normally closed that are momentarily open by specific stimuli
56
List the two types of channels:
1. ligand gated
| 2. voltage gated
57
Direction of ion travel across a membrane:
high to low concentration
58
If an open gate allows the passage of Na, Cl, and Ca to enter the cell, what moves out?
K
59
Glial cells have a significant role in neuron function because they provide [...] to neurons, maintain the [...] of neurons, and provide [...] function.
physical support; chemical environment; immunological
60
What are the 4 principal types of glial cells?
1. oligodendroglia
2. Schwann cells
3. astrocytes
4. microglia
61
Schwann cells produce myelin sheath for the [...] while oligodendroglia produces for the [...].
PNS; CNS
62
Each oligodendroglia in the [...] send out [...] that wrap around segments of [...] nearby axons to form myelin sheath.
CNS; multiple sheetlike arms; multiple
63
Which myelin sheath producer releases nerve growth factors when an axon is damaged or needs to grow?
Schwann cells
64
Describe astrocytes:
large, star-shaped cells that have numerous extensions
65
Astrocytes [...] with neurons and provide [...]; in addition, they help to maintain the [...] around neurons and modulate the [...] as well by taking up excess [...] that might otherwise damage cells.
intertwine; structural support; ionic environment; chemical environment; neurochemicals
66
Which glial cell is most likely to help necessary material to move from the blood to nerve cells?
astrocytes
67
Microglial:
small scavengers that collect at sites of neuron damage to remove dying cells
68
Which glial cell is the primary source of immune response in the CNS?
microglial
69
Which glial cell is responsible for the inflammation reaction that occurs after brain damage?
microglia
70
Which glial cell inhibits re-growth of axons following neuron damage?
oligodendroglia
71
Which glial cell performs gliosis?
astrocytes
72
Which glial cell provides a channel to guide axons to target?
Schwann cells
73
Which glial cell has a potential role in the etiology of schizophrenia?
microglia
74
When the normal resting electrical charge of a neuron is distributed sufficiently by incoming signals from other cells...
a threshold is reached that initiates the action potential to convey a message along the axon to the terminal
75
Resting membrane potential:
electrical charge inside the cell
76
The inside of the neuron is more [...] than the outside, making the neuron [...] in its resting state.
negative; polarized
77
What would the voltmeter read when measuring the inside resting potential?
-70 mV
78
What is responsible for creating a membrane potential?
uneven distribution of ions and selective permeability of the membrane
79
If the inside is more negative at the resting potential, what contributes to the negative charge?
negatively charged AA and proteins that cannot leave the cell
80
Electrostatic potential explains why...
K ion is pulled into the cell
81
Equilibrium potential for potassium:
when the two forces on K are balance
inward electrostatic pressure and outward concentration gradient
82
For every 3 ions of Na pumped out...
two K ions are pumped in
83
Na-K pump:
energy dependent pump that contributes to the resting potential
84
Which ion has a greater ability to move freely through ungated channels?
K
85
Action potential can be generated when the membrane potential...
is changed from -70 mV to the threshold for firing -50 mV
86
What happens at -50mV?
voltage-gated Na channels open and generate a rapid change in membrane potential
87
List characteristics of hyperpolarization (5):
1. more negative inside the cell
2. membrane potential is farther from threshold
3. ISPS caused by Cl channel open/entry
4. ISPS cause by K channel open/entry
5. greater stimulation produces larger hyperpolarizations
88
List characteristics of depolarization (4):
1. more positive inside the cell
2. membrane potential moves toward threshold
3. EPSP caused by Na channel open/entry
4. greater stimulation produces larger polarizations
89
Local potentials are induced by...
small, local changes in ion distribution/electrical potential differences
90
If Na ions enter the cell the membrane potential is brought closer to...
reaching the threshold for firing
91
Depolarization is [...] and hyperpolarization is [...].
excitatory; inhibitory
92
Neurotransmitters act on the [...] membrane.
postsynaptic
93
List the significant characteristics of local potentials:
1. graded-- the larger the stimulus, the greater is the magnitude of hyper/depolarization
2. rapidly decay once the stimulus stops
3. integration-- summation; they can add to amplify change or cancel each other out
94
Where in the neuron does integration occur?
within the axon hillock
95
The summation of local potentials at the axon hillock is responsible for generation of the [...].
action potential
96
At the voltage -50mV, the [...] occurs, causing [...] ions to be driven in the cell and changing the membrane potential to [...].
action potential; Na; +40mV
97
Absolute refractory period is the time that...
the Na ion channels are closed and cannot be open, regardless of the amount of excitation
98
What is the maximum number of action potentials that can occur?
1200 impulses/second
99
During the rising phase, the change in membrane potential due to [...] entry causes the voltage-gated [...] channels to open and move [...] of the cell.
Na ion; K ion; K ions
100
The membrane potential actually [...] the resting potential. This means the membrane is [...] for a short amount of time.
overshoots; hyperpolarized
101
What can relieve the membrane when it is hyperpolarized?
Until the excess K ion diffuses away or is exchanged for Na ion by the Na-K pump
102
The brief hyperpolarizing phase is called the ...
relative refractory period
103
T/F: The size of an action potential is related to the amount of stimulation.
false the two are unrelated (all-or-none)
104
Does the action potential decrease in size as it moves down an axon?
no, it is nondecremental
105
In myelinated axons (compared to unmylelinated), the speed of conduction is as much as [...] times quicker.
15
106
Saltatory conduction:
the jump of conduction along a myelinated axon; action potential occurs only at the nodes of Ranvier in these types of axons
107
Myelinated axons use [...] energy because the Na/K pump only has to work [...].
less; at the nodes rather than all along the axon
108
Anesthetics impair axonal conduction by...
blocking voltage-gated Na channels
109
Blocking the Na channel means an [...] cannot occur, and transmission of the pain signal cannot [...].
action potential; reach the brain
110
Several antiepileptic drugs also block [...] channels. It [...] to close these channels so it can prolong the [...] state of the channel, slowing down the [...].
Na ion; selectively binds; refractory; firing rate
111
PNS can be divided into:
somatic and autonomic nervous system
112
Somatic nervous system:
controls voluntary muscles with both spinal nerves and cranial nerves
113
Autonomic nervous system:
autonomic nerves and some cranial nerves that control the function of organs and glands (EDIT)
114
The autonomic nervous system has both the...
sympathetic and parasympathetic divisions
115
The somatic nervous system can be referred to [...] nerves as each spinal nerve consists of [...] or [...] neurons.
sensory; motor
116
Within each mixed nerve, sensory information is carried from the [...] and from [...] into the [...] of the spinal cord by neurons that have their cell bodies in the [...]. These are known as [...].
surface of the body; muscles; dorsal horn; dorsal root ganglion; sensory afferents
117
Mixed nerves also have motor neurons, which are cells beginning in the [...] of the spinal cord and ending on [...]. These are called [...] and are responsible for [...].
ventral horn; skeletal muscles; motor efferents; voluntary movements
118
Which cranial nerve innervates organs in the viscera?
X; the vagus nerve
119
The vagus nerve consists of ...
both sensory and motor neurons
120
What do the nerves in the ANS regulate?
the internal environment; innervate smooth muscles (heart, intestine, urinary bladder, glands)
121
ANS purpose:
control functions that provide/conserve energy appropriate to the environmental needs of the organism
122
List the two divisions of the ANS:
1. sympathetic
| 2. parasympathetic
123
Sympathetic division predominates when...
energy expenditure is necessary; times of stress, excitment, and exertion
124
Fight or flight is what division of the nervous system?
sympathetic
125
Parasympathetic division predominates at times when...
energy reserves can be conserved and stored for later use
126
What are some examples of the parasympathetic division at work?
increase of salivation, digestion, storage of glucose and other nutrients and also slows heart rate and decreases respiration
127
What are some examples of the sympathetic division at work?
increases heart rate and blood pressure, stimulates secretion of adrenaline, increases blood flow to skeletal muscles
128
In contrast, the cell bodies of efferent parasympathetic neurons are located either in the [...] or in the [...] of the spinal cord in the [...].
brain; ventral horn; sacral region
129
Which cranial nerves are efferent parasympathetic?
3, 7, 9, 10
130
Preganglionic fiber release [...]..
acetylcholine
131
The delicate tissues that layer the brain and spinal cord are also known as [...].
meninges
132
List the 3 meninges:
1. dura mater
2. arachnoid
3. pia mater
133
Dura mater:
toughest and outermost layer
134
Arachnoid:
just below the dura, membrane with a web-like sublayer filled with CSF (subarachnoid)
