Unit 2 - Neurophysiology Flashcards
(99 cards)
1
Q
what are the two main components found in the nervous system
A
- Central Nervous System (CNS)
- Peripheral Nervous System (PNS)
2
Q
what is the CNS composed of
A
- brain
- spinal cord
3
Q
what is the PNS composed of
A
- everything but the brain and spinal cord (in the nervous system)
4
Q
define: nuclei [CNS]
A
clusters of cell bodies
5
Q
define: tracts [CNS]
A
bundles of axons forming a pathway
6
Q
define: ascending tracts
A
tracts that carry sensory information to the brain
7
Q
define: descending tracts
A
tracts that carry commands from the brain to motor neurons
8
Q
define: peripheral nerves
A
bundles of axons of sensory or motor neurons existing outside of the CNS (same as tracts but found in the PNS)
9
Q
define: ganglia [PNS]
A
clusters of cell bodies (same as nuclei within CNS but in PNS)
10
Q
what are the four components of the nervous system (information flow)
A
- receptors
- afferent (sensory) neurons
- interneurons
- efferent (motor) neurons
11
Q
what do receptors do
A
convert stimuli into electrical signals
12
Q
what do receptors transit information to
A
afferent neurons
13
Q
what do afferent neurons transmit sensory information to
A
the CNS
14
Q
where are the cell bodies of afferent neurons located
A
outside the CNS
15
Q
where are interneurons located
A
inside the CNS
16
Q
what percent of neurons do interneurons make up
A
96%
17
Q
where do interneurons transmit information signals
A
within the CNS:
- laterally within the spinal cord
- vertically to the brain
18
Q
where are efferent neurons located
A
within the CNS
19
Q
how do efferent neurons transmit information to effectors
A
through cytoplasmic extensions
20
Q
what are examples of effectors in regards to the nervous system
A
muscles, glands, etc.
21
Q
what are the two cell types in the nervous systems
A
- neurons
- glial cells
22
Q
which type of cell transmits signals over long distances
A
neurons
23
Q
what are the 4 main parts of a neuron
A
- soma
- dendrites
- axon
- axon terminals
24
Q
which part of a neuron contains the nucleus and all the biosynthetic machinery
A
soma
25
which part of a neuron keeps the cell functioning and alive
soma
26
which part of the neuron transmits electrical signals towards the soma
dendrites
27
which part of the neuron transmits electrical signals away from the soma
axon
28
which part of a neuron has a tree structure, branching out
dendrites
29
which part of a neuron is cytoplasmic extension that send out information
axon
30
which part of a neuron is the connection to another cell
axon terminals
31
what are the tree parts of a synapse
- presynaptic axon terminal
- postsynaptic dendrite
- synaptic cleft
32
define: pseudounipolar neurons
somatic sensory neurons
33
what is a feature of pseudounipolar neurons
axons and dentrides fuse during development to form one long process
34
define: bipolar neurons
smell/vision sensory neurons
35
what do bipolar neurons componse of
a single axon and dendrite
36
define: anaxonic neurons
interneurons
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what is a feature of anaxonic neurons
no apparent axon
38
what are features of multipolar - CNS neurons
- highly branched
- no long extensions
39
what are features of multipolar - efferent neurons
- 5-7 dendrites
- single long axon
40
what is the ratio of glial cells to neurons
50 : 1
41
how do glial cells communicate with each other and with nearby neurons
using electrical and chemical signals
42
what are the two main ways glial cells contribute to the function of neurons
- aid in nerve impulse conduction
- maintain the microenvironment around neurons
43
what are the two types of glial cells of the PNS
- Schwann cells
- Satellite cells
44
who do schwann cells form
myelin - layers of membrane around the axon
45
what are found between the layers of schwann cells
gap junctions
46
what does myelin act as
an electrical insulator
47
define: satellite cells
non-myelinating schawann cells
48
what do satellite cells support
nerve cell bodies
49
define: nodes of ranvier
small gaps in myelin
50
what are the four types of glial cells of the CNS
- oligodendria
- astroglia
- microglia
- ependymal cells
51
define: oligodendria
CNS version of schwann cell, wrap around axons and form myelin
52
what is a key difference between oligodendria and schwann cells
one oligodendria can wrap around multiple axons
53
what cell type of glial cell (CNS) contacts blood vessels and neurons for nutrient transfer
astroglia
54
what type of glial cell (CNS) maintains the neuron microenvironment
astroglia
55
what type of glial cell (CNS) are specialized immune cells, removing damaged cells/foreign invaders
microglia
56
what type of glial cell (CNS) are epithelial cells that produce cerebral spinal fluid (CSF)
ependymal cells
57
what type of glial cells create selectively permeable barriers between compartments of the brain
ependymal cells
58
how do neurons transmit electrical impulses
they use energy stores as an electro-chemical gradient
59
Coulomb's law: electrical force increases as the strength (number of charges) ____ and decreases as the distance between the charges ____
increases; increases
60
is the ICF positively or negatively charged
negatively
61
is the ECF positively or negatively charged
positively
62
what part of the cell is an electrical insulator
the cell membrane
63
what allows current to move through the cell membrane
ion channels
64
what are the two situations where there is no net movement across the cell
- no concentration gradient and no electrical gradient
- concentration gradient exactly balances electrical gradient (equilibrium state)
65
what does the Nernst equation let you calculate
the electrical potential of the cell needed to generate an equilibrium state if you know the concentration gradient
66
what lets you predict whether an ion is going to move into or out of the cell
comparing the actual membrane potential of the cell to the equilibrium potential for that ion
67
why is the inside of a cell electronegative at rest
the presence of negatively charged ions (mostly phosphate) & proteins
68
ions with positive equilibrium potential (calculated with the Nernst equation) will tend to move ___ a resting cell
into
69
ions with very negative equilibrium (calculated with the Nernst equation) will tend to move ____ a resting cell
out of
70
define: resting membrane potential
the charge difference between the inside and outside of a cell
71
what is "membrane potential" a result of
the electrical and chemical gradients caused by the distribution of ions across the cell membrane
72
what sets the resting membrane potential
the concentration of each of the ions and their relative permeabilities
73
an ion's contribution to resting membrane potential is ____ to its permeability
proportional
74
molecules that cannot move across cell membrane ____ contribute to resting membrane potential
do not
75
what does the Goldman Equation factor in (extension of Nernst equation)
the permeability of each ion
76
how many more times more permeable is K+ than Na+
about 40X
77
which ions are the most important in setting resting membrane potential
K+ ions
78
what is the resting membrane potential of a typical neuron
-70mV
79
what is the equilibirum potential of K+
-90mV
80
what is the equilibrium potential of Na+
+60mV
81
why don't the K+ and Na+ ions leak in and out until they reach their equilibrium potentials
Na+/K+ ATPase using energy to maintain those concentrations
82
what is the ion result of Na+/K+ ATPase
2 Na+ out and 2 K+ in
83
what do gated channels in neurons do
regulate ion movement
84
what are the three ways that gated channels are gated
- mechanically
- chemically
- voltage
85
where are mechanically gated channels found
in sensory neurons
86
when do mechanically gated channels open
in response to physical forces
87
when do chemically gated channels open
in response to ligands such as neurotransmitters, neuromodulators, or intracellular signal molecules
88
when do volate-gated channels open
in response to changes of voltage
89
what are voltage-gated channels important for
initiation and conduction of electrical signals
90
what are the 4 major selective types of gated channels
- Na+
- K+
- Ca2+
- Cl-
91
what do neurons use to transmit electrical signals
energy stored in electrical and chemical gradients
92
define: depolarization
decrease in membrane potential difference, cell becomes less negative
93
define: hyperpolarization
an increase in the membrane potential difference, cell becomes more negative
94
how do cells change their membrane potential
change the membrane ion permeability
95
what is the slow way to change membrane permeability
change total number of channels
96
what is the fast way of changing membrane permeability
open or close existing protein channels
97
why does Na+ contribute minimally to resting membrane potential
low permeability
98
why is Na+ critical
it generates changes in membrane potential that cause electrical signals
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