Neurophysiology - Unit 2 Flashcards
1
Q
One of 2 key control systems where the other one is the endocrine system is
A
nervous system
2
Q
3 functions of the nervous system
A
-receives information
-integrates information
-transduces information
3
Q
receives information
A
Using sensory neurons (receptors) to receive from external environment
4
Q
integrates information
A
integrates information
Organizes the information and brings it together with already stored information
5
Q
transduces information
A
sends appropriate signals to the appropriate target (mostly muscles or glands)
6
Q
Put in order:
1. afferent pathway
2. efferent pathway
3. response
4. target or effector
5. integrating center
6. sensor or receptor
7. stimulus
A
7, 6, 1, 5, 2, 4, 3
7
Q
2 main parts of the nervous system
A
central nervous system and peripheral nervous system
8
Q
The central nervous system made up of
A
brain and spinal cord
9
Q
part of the nervous system outside of the brain and spinal cord
A
Peripheral Nervous System (PNS)
10
Q
Part of the nervous system that consists of sensory (afferent) and motor (efferent) neurons
A
Peripheral Nervous System (PNS)
11
Q
sensory neurons
A
afferent
12
Q
motor neurons
A
efferent
13
Q
2 basic kinds of cells found in the nervous system
A
neurons and glial cells
14
Q
cells in the nervous system that generate and transmit – often over long distances are called
A
-electrical impulses
-neurons
14
Q
4 main parts of a neuron
(refer to diagram)
A
-soma
-dendrites
-axon
-axon terminals
14
Q
cell body of a neuron that contains the - and all - machinery is called the
A
-nucleus
-biosynthetic
-called the soma
14
Q
Nuclei
A
clusters of cell bodies in the CNS
14
Q
ganglia
A
clusters of cell bodies in the PNS
15
Q
the center of all chemical processes in a neuron, keeps the cell functioning and alive
A
soma
15
Q
transmits electrical signals towards the soma
A
dentrites
15
Q
slender processes that receive information
A
dentrites
16
Q
cytoplasmic extension that sends out information
A
axon
17
Q
Structure that transmits – away from the soma is called the
A
-electrical signals
-axon
18
Q
tract
A
bundles of axons in the CNS
19
nerves
bundles of axons in the PNS
20
End of axon that connects between neuron and other cells
axon terminals
21
Axon terminals participate as a part of the -, -
-synapse, presynaptic
22
Neurons can be classified by structure. The 3 types of neurons are
-pseudounipolar
-bipolar
-multipolar
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Pseudounipolar neurons are -- neurons
somatic sensory
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- and - fuse during development into a single process-
-axons and dentrites
-these are pseudounipolar neurons
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Bipolar neurons are -/- neurons
Bipolar
these are smell/vision sensory neurons
26
Bipolar neurons contain a single - and -
and they are - focused (nose, eyes, ears)
-axon and dentrite
-organ focused
27
Multipolar neurons are - and - neurons
-CNS and Efferent
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Multipolar neuron structure
-have a single axon process
-have two or more dendrites
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Neurons can be classified according to function. 3 types of neurons are
-afferent (sensory) neurons
-interneurons
-efferent (motor) neurons
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Afferent (sensory) neuron function
neurons that receive information from receptor cells and transmit sensory information TO the CNS
31
Cell bodies of afferent neurons are located
outside the CNS
32
Afferent (sensory neurons) structure and where do they transmit information from and to?
Have long cytoplasmic extensions that transmit information to cells (interneurons) within the CNS
33
Interneurons are located
-inside of the CNS
34
makes up 96% of all neurons
interneurons
35
How Interneurons transmit information
transmit information signals within the CNS either laterally within the spinal cord or vertically to the brain
36
These neurons integrate information received from afferent neurons and previous information and transmit signals to efferent neurons
interneurons
37
receive information from the interneurons
efferent (motor) neurons
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the cell bodies of the efferent neuron are located
within the CNS
39
efferent (motor) neurons
cytoplasmic extensions transmit information to the effectors
40
glial cell function
-cells that are associated with neurons
-main job is maintenance
-involved in HOW information is sent
40
effectors
Carry out the message, such as muscles and glands etc...
41
these cells do not carry electrical signals (information) over long distances
glial cells
42
glial cells contribute to the function of neurons in two main ways
-aid in nerve impulse conduction
-maintain the microenvironment around the neurons
43
these cells communicate with each other and with nearly neurons using electrical and chemical signals
glial cells
44
2 types of PNS glial cells
-schwann cells
-satellite cells
45
special PNS glial cells that are wrapped around axons
schwann cells
46
PNS glial cells that forms myelin (layers of membrane)
schwann cells
47
acts as an electrical insulator in Schwann cells
myelin
48
these are non-myelinating Schwann (glial) cells in the PNS
satellite cells
49
-PNS glial cell that support nerve cell bodies (soma)
-provides nutrients, protection, interact with blood, etc...
satellite cells
50
Most glial cells are found in the
CNS
51
4 types of glial cells in the CNS are
-Oligodendria (ologodendrocytes)
-Astroglia
-Microglia
-Ependymal cells
52
-Oligodendria (ologodendrocytes) vs. Schwann cell
Oligodendria (ologodendrocytes) is the CNS version of the Schwann cell
53
-Oligodendria (ologodendrocytes)
wrap around the axons, forming myelin to insulate the CNS axons
54
Astroglia (astrocytes) are small - shaped cells in the - that maintain - by maintaining the --
small star shaped cells in the CNS (glial cell) that maintain homeostasis by maintaining the extracellular fluid
55
Type of CNS glial cell that:
-contacts -- and -
-maintain neuron microenvironment, helps maintain homeostasis in extracellular fluid around neurons
-blood vessels and neurons
-Astroglia (astrocytes)
56
Microglia
a type of CNS glial cell that is a very small specialized immune cell (macrophage-like)
57
Microglia
CNS glial cell whose function is to remove damaged cells and foreign invaders
-prevents further damage by creating blocks around the axon
58
Ependymal cells
Epithelial cells that produce cerebrospinal fluid
59
Ependymal cells function in the brain?
-CNS glial cell that create selectively permeable barrier between compartments of the brain
-create new synaptic connections and develop the brain etc...
60
-CNS glial cell that serve as - cells that create more Oligodendria (ologodendrocytes), Astroglia (astrocytes), and Microglia glial cells
-stem cells
Ependymal cells
61
CNS glial cell that has gap junctions that allow proteins through
Oligodendria (ologodendrocytes)
62
create a flow chart of the nervous system that includes:
-CNS
-PNS
-Brain
-Motor
-Sensory
-Spinal cord
-somatic
-Autonomic
-parasympathetic
-sympathetic
page 23 of course notes
63
How do neurons transmit electrical impulses?
via energy stored as an electrochemical gradient
64
Electrical principles:
-the human body is electronically neutral because
the law of conservation of electrical change states the amount of electrical charge produced in a process is zero
65
Electrical principles:
opposite charges - and like charges -
attract and repel
66
Electrical principles:
separating positive and negative charges requires
energy
67
Electrical principles:
The cell membrane is an electrical insulator, which allows for
the separation of electrical charge
68
Electrical principles:
A difference in the charge between the inside and outside of the cell sets up an electrical gradient. ICF (intracellular fluid) has net - charge and the ECF (extracellular fluid) has a net -
negative charge and positive charge
69
Electrical principles:
-allows electrical charge to move through the membrane
Ion channels
70
Membrane potential:
all living cells have a - potential
-membrane
-they are polarized electrically
71
Membrane potential:
There is a relative difference of the number of - and the number of - on either side of the membrane
-cations (+ve charges)
-anions (-ve charges)
72
What is membrane potential?
The difference of the electrical potential between the inside and outside of the cell
73
Membrane potential:
Excitable tissues
Nervous and muscle
74
Excitable tissues (muscle and nervous) use rapid changes of the membrane potential when they are excited, which allows
neurons to conduct an electrical signal and muscle cells to contract
75
membrane potential is measured in
millivolts (mV)
76
Distribution and movement of ions:
Membrane electrical properties are determined by two factors:
1. An unequal distribution of key ions between the ICF and the ECF
2. Selective movement of these ions across the membrane
77
1. An unequal distribution of key ions between the ICF and the ECF
-Na+ and Ca2+ and Cl- are higher in -
ECF
78
1. An unequal distribution of key ions between the ICF and the ECF
-K+ is higher in -
ICF
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1. An unequal distribution of key ions between the ICF and the ECF
-Anions are ... and they are higher in the -
-large, negatively charged intercellular proteins
-ICF
80
2. Selective movement of these ions across the membrane
-Because of their size, the anions ...
do not move across the membrane
81
Concentration differences in Na+ and K+ are maintained by the Na+-K+ pump, which uses... to drive ions - the gradient
-ATP for energy
-against
82
Ions can move across the membrane through specific - -
protein channels
83
The specific protein channels that ions can move across the membrane from can be - or -
passive (leak) or gated
84
-The specific protein channels that ions can move across the membrane from can be passive (leak) or gated
-This makes it easier for ( which ion) to move passively due to the large number of passive channels for (which ion) compared to (what other ion)
-K+
-compared to Na+
85
Equilibrium Potential
Equilibrium Potential
The membrane potential that exactly opposes the concentration gradient of an ion. This is where the electrical and chemical forces acting on the ion are equal and opposite
86
The point where the cell's electrical charge balances the ion's movement due to its concentration, so the ion stops moving in or out.
In other words, when the cell's charge (membrane potential) and the difference in ion amounts (concentration gradient) balance each other, so the ion doesn’t move in or out.
Equilibrium Potential (in simpler terms)
87
For any - ion you can calculate the -- of the cell needed to generate an equilibrium state, if you know the --
single, electrical potential, concentration gradient
88
The Nernst equation
Calculates the equilibrium potential for one ion based on its charge and the difference in its concentration inside and outside the cell.
89
E-ion =
equilibrium potential for one specific ion (in mV)
90
z =
electrical charge of the ion
91
61 is 2.303 RT/F at 37 degrees celcius (R = gas constant, T = temperature (in K), and F = Faraday constant)
Refer to the Nernst Equation
91
The equilibrium potential for K+ for a typical neuron is approx -
-90mV
Note: K+ flows outside until outside becomes too positive, makes inside negative
92
The equilbrium potential for Na+ in a typical neuron is approx -
+60mV
Note: Na+ flows inside the cell until the inside becomes too positive, makes the outside negative
93
The Nernst equation looks at what membrane potential would be if the membrane was permeable to - ion
even through there are multiple ions that contribute the the membrane potential in a cell in living systems
only one
94
Na+-K+ pump role is to
maintain the cell at resting potential, resist equilibrium potential
95
The charge difference between the inside and outside of a cell at REST is called the
Resting Membrane Potential
96
For a typical neuron, the resting membrane potential is - mV
-70mV
97
Why is it called the resting membrane potential?
-Resting membrane potential = a steady state (not changing with time)
-membrane potential = the electrical and chemical gradients caused by the distribution of ions across the cell membrane is a source of stored (potential) energy
98
The electrical and chemical gradients caused by the distribution of ions across the cell membrane is a source of stored (potential) energy
membrane potential
99
When a neuron sends a signal it is no longer at rest, it moves away from the
resting membrane potential
100
What sets the resting membrane potential?
The concentrations of each of the ions and their relative permeability
101
Which one of the ions (Na+, Cl-, Ca2+, and K+) are higher in the ECF or ICF?
-Na+, Cl-, Ca2+ are higher in the ECF
-K+ is higher in the ICF
102
The cell membrane is more - to certain ions, such as -
-permeable
-K+
Meaning: some ions can cross the membrane much more easily than others
103
The ion contribution to the resting membrane potential is - to its permeability
proportional
Note: the more easily it can cross the membrane, the more important it will be for the resting membrane potential
104
Molecules that cannot move across the membrane ... to the resting membrane potential
do not contribute
105
Meaning of: The Goldman-Hodgkin-Katz (GHK) equation predicts -- using multiple -
-membrane potential
-multiple ions
The Goldman-Hodgkin-Katz (GHK) equation calculates the cell's membrane potential by considering the concentration and movement (permeability) of multiple ions, like sodium, potassium, and chloride.
106
The GHK equation considers the -- of each ion
-membrane permeability
-Meaning: The GHK equation considers both the concentrations of multiple ions (like sodium, potassium, and chloride) and how easily each ion can cross the membrane (its permeability). This means it calculates the membrane potential based on how much each ion contributes, depending on its concentration and how permeable the membrane is to that ion.
107
Vm =
61 is 2.303 RT/F at 37 degrees Celsius
P =
Refer to GHK equation
-Vm = Resting membrane potential (in mV)
-P = permeability of the membrane to a specific ion
108
Resting membrane potential is calculated by
adding the (concentration gradient x membrane permeability) for each ion
Note: if a membrane is not permeable to a given ion the ion drops out of the equation
109
Creating Electrical Signals:
If there is a change in the permeability of the cell to a given ion,
then the ion can move down its electrical gradient
110
Creating Electrical Signals:
Recall that the Na+-K+ pump - the passive movement of Na+ and K+ --
-offsets
-at rest
Meaning: The Na+-K+ pump helps maintain balance by moving sodium (Na+) out of the cell and potassium (K+) into the cell, counteracting their natural tendency to passively move in the opposite directions.
111
Creating Electrical Signals:
It takes the movement of ... to change membrane potential away from resting membrane potential ) recall that is (-70mV)
only a few ions
112
Creating Electrical Signals:
Two main concepts, what are the two types of polarization?
Depolarization
Hyperpolarization
113
Creating Electrical Signals:
Depolarization
-A decrease in the membrane potential difference
-Cell membrane potential becomes less negative
114
Creating Electrical Signals:
Hyperpolarization
-An increase in the membrane potential difference
-Cell membrane potential becomes more negative
115
Concentration gradients ... with large changes of membrane potential
do not change even
116
Depolarization and Hyperpolarization with Na+ and K+
-Depolarization: Happens when sodium (Na⁺) enters the cell, making the inside less negative (closer to positive).
-Hyperpolarization: Happens when potassium (K⁺) leaves the cell or chloride (Cl⁻) enters, making the inside more negative.
117
Controlling Ion Permeability:
Neurons contain a variety of --- that regulate the movement of ions
gated ion channels
118
Controlling Ion Permeability:
Gated channels can be controlled (open or close) by -
stimuli
118
Controlling Ion Permeability:
3 types of gated ion channels
mechanically gated, ligand gated, and voltage gated
119
mechanically gated ion channels
mechanically gated
type of ion channel found in sensory neurons and open in response to physical forces
120
Ligand-gated ion channels
Respond to ligands such as neurotransmitters
121
voltage-gated ion channels
respond to changes of voltage
122
voltage-gated ion channels are important in
Initiation and conduction of electrical signals along the axon
123
4 major types of selective ion channels in the neuron
1. Na+ channels
2. K+ channels
3. Ca2+ channels
4. Cl- channels
124
Two types of signals generated by neurons
1. short distance signals are those that travel short distances
2. long distance signals are those that travel long distances
125
Short distance signals, those that travel short distances
graded potential
126
Long distance signals, those that travel long distances
action potential
127
Match with the type of polarization: Depolarization or Hyperpolarization
1. Na+ entry
2. K+ exit
3. Ca2+ entry
4. Cl- entry
Depolarization:
Na+ entry
Ca2+ entry
Hyperpolarization:
K+ exit
Cl- entry
128
Graded Potentials:
Graded potentials could be - or -
depolarizations or hyperpolarizations
129
Graded Potentials occur in
the dendrites or cell body of neurons
130
Graded Potentials are triggered by the - or - of ion channels
opening or closing
131
Graded Potentials are started by - entering the cell from the -
ions, extracellular fluid
132
Graded Potentials are called graded because
the amplitude of the potential is proportional to the strength of the triggering event
133
Graded potentials travel only a short distance through the neuron because
Graded potentials lose strength due to
1. Current leak - some positive charges leak back with the depolarization wave (means: As the electrical signal travels, some positive charges (like Na⁺ ions) leak out through tiny openings in the cell membrane, which weakens the signal as it moves farther.)
2. Cytoplasmic resistance - cytoplasm restricts flow of current
134
