Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BMSC 207 > Nervous System > Flashcards

Nervous System Flashcards

1
Q

Membrane Potential

A

the electrical disequilibrium that exists between the ECF and ICF is called membrane potential difference or membrane potential (Vm)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Equilibrium Potential

A

For any given concentration gradient of a single ion, the membrane potential that exactly opposes the concentration gradient is known as the equilibrium potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What impacts resting membrane potential the most?

A

The Potassium + Channel.
Making a negative intracellular charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Two Factors that incfuence a cells membrane potential?

A

the permeability of the membrane to those ions
the co contraption gradients of different ions across a membrane ( Na+, K+ and Ca2+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Depolarization

A

If the membrane potential becomes less negative than the resting potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Hyperpolarization

A

if the membrane potential becomes more negative, the cell hyperpolarizes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Afferent

A

Carry information towards CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Efferent

A

Cary information away from CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

CNS

A

brain
spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Peripheral Nervous System (PNS)

A

Nerve tissue outside the CNS: Cranial nerves and branches, spinal nerves and branches, ganglia, plexuses and sensory receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Afferent division

A

Somatic sensory
Visceral Sensory
Special sensory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Efferent division

A

Somatic motor
Autonomic motor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

A cell body (soma)

A

considered the control center, with processes that extend outward; dendrites and axons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Dendrites

A

Receive incoming signals from neighbouring cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Axons

A

carry outgoing signals from the integration centre to target cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Presynaptic terminals

A

contains transmitting elements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Pseudounipolar

A

Neurons have a single process called the axon. During development, the dendrite fused with the axon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Bipolar

A

Bipolar neurons have two relatively equal fibres extending off the central cell body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Anaxonic

A

Multipolar CNS interneurons are highly branched but lack long extensions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Multipolar

A

A typical multipolar efferent neutron has 5-7 dendrites, each branching four to six times. A single long axon may branch several times and end at enlarged axon terminals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Afferent

A

Sensory
Carry information about temperature, pressure, light and other stimuli to the CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Interneurons

A

Complex branching neurons that fascilitate communication between neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Efferent

A

Motor and Autonomic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Motor Efferent

A

control skeletal muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Autonomic Efferent

A

Influences many internal organs
Sympathetic and parasympathetic
Usually have axon terminals or varicosities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Axonal Transport

A

The axon is specialized to convey chemical and electrical signals that require a variety of different types of proteins
The axon contains many types of fibres and filaments but lacks ribosomes and ER necessary for protein production, therefore proteins must be produced un the cell body and transported down the axon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Fast Axonal Transport

A

Membrane bound proteins and organelles (vesicles or mitochondria)
Anterograde: Cell body to axon terminal, up to 400mm/day
Retrograde: Axon terminal to cell body, 200mm/day

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Slow Axonal Transport

A

Cytoplasmic proteins (enzymes) and cytoskeleton proteins
Anterograde, up to 8mm/day some evidence for retro
Not well characterized, may be slower due to frequent periods of pausing of movements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Kinesins

A

Anterograde transport

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Dyneins

A

Retrograde transport

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Synapses

A

Majority are chemical synapses
Space contains extracellular matrix (proteins and carbohydrates) that hold pre and post synaptic cells in close proximity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Myelin forming Glia

A

A substance composed of multiple concentric of multiple concentric layers of phospholipid membrane wrapped around an axon
Provides structural stability, acts an insulation around the axon to speed up electrical signals (saltatory conduction), supply trophic factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Multiple Sclerosis

A

Disorder resulting from demolition in brain and spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

MS symtoms

A

Sensory, motor and cognitive issues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Satellite Glial cells

A

Exist within ganglia (bundle of cell bodies) in the PNS
Form a supportive capsule around the cell bodies for neurons (sensory and autonomic)
Supply nutrients
Structural support, provide a protective cushion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Astrocytes

A

Highly branched glial cells in CNS believes to make up half of all cells in the Brain
Several subtypes, form a functional network

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Functions of Astrocytes

A

The up and release chemicals at synapses
Provide neurons with substrates for ATP production
help maintain homeostasis in the ECF( take up K+ and H20)
Surround vessels
part of the blood brain barrier
influence vascular dynamics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Microglia

A

Specilaized immune cells that reside in the CNS
Serve to protect and preserve neuron cells from pathogens and facilitate recovery from metabolic insults

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Ependymal Cells

A

Line fluid filled cavities in the brain and spinal cord
Protection
Chemical Stability
Clearing wastes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Peripheral Neuron Injury

A

CNS repair less likely to occur naturally, glia tend to seal off and form scar tissue. Lack Organelles. Reforms Synapse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Electrical Signals in Neurons

A

Neurons and muscle cells are “excitable” due to their ability to propagate electrical signals over long distances in response to a stimulus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Two factors influence the membrane potential

A

The uneven distribution of ions across the cell membrane (concentrations gradients)
Membrane permeability to those ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What does the Nernest Equation describe

A

Nernest equation described the membrane potential that would result if the membrane were completely permeable to only one ion (the equilibrium potential for that ion)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Electrical Signals: GHK Equation

A

Predicts membrane potential that results from the contribution of all ions that can cross the membrane
Determined as the combined contribution of each ion (concentration x permeability) to the membrane potential
Different from Nernest Equation., which calculates the equilibrium potential for a single ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Electrical signals in neurons

A

Resting membrane potential in most neurons is -70mV

Mainly due to K+
Na+ contributes slightly (very few Na+ leak channels)
Cl- minimally, equilibrium potential close to resting membrane potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Ion movements create electrical signals

A

A change in the K+ concentration gradient or change in permeability to ions (Na+, K+, Ca2+ or Cl-) alters the membrane potential

  • A significant change in membrane potential (-70mV to +30mV) does not indicate a change in concentration gradients for a given ion.
  • very few ions need to move to alter the membrane potential (to alter the membrane potential by 100mV, 1 out of every 100,000 K+ ions must enter or leave the cell), which is a tiny fraction of total K+ in cell
  • the concentration gradients for ions remain relatively constant during most alterations in membrane potential
47
Q

5 major types of ion channels

A

Na+ channels
K+ Channels
Ca2+ channels
Cl- channel
Non covalent cation channels (allow Na+ and K+ to pass)
Conductance
Varies with the gating state of the channel
Channel protein isoform

48
Q

Conductance

A

The ease with with which ions flow through a channel is known as the channels conductance

49
Q

Types of Gated Channels

A

Mechanically Gated Channels
Chemically gated ion channels
Voltage gated channels

50
Q

Mechanically gated channels

A

Open in response to physical forces (pressure or stretch), found in sensory neurons

51
Q

Chemically gates ion channels

A

In neurons respond to ligands including extracellular neurotransmitters an neuromodulatorsor intracellular signalling modules

52
Q

Voltage gated channels

A

Respond to changes in the cells membrane potential

53
Q

Variation in gated channels

A
  • Voltage for channel opening can vary from channel to channel
  • the speed at which channels open or close varies
    -many channels that open to depolarization will close during repolarization
  • Some channels spontaneously inactivate
54
Q

Channel’s Subtypes

A
  • Varying properties between subtypes
  • Multiple isoforms that express different gating kinetics
  • modifies by different proteins and pathways
55
Q

Current flow and Ohm’s Law

A
  • Current flow (I) is directly proportional to the electrical potential difference (in volts, V) between two points and inversely proportional to the resistance (R). I = V/R
56
Q

Two sources of resistance in a cell:

A

Membrane resistance (Rm)
Internal resistance of the cytoplasm (Ri)

57
Q

Membrane Resistance

A

Resistance of the phospholipid bilayer

58
Q

Internal resistance of cytoplasm

A

Cytoplasmic composition and size of the cell

59
Q

Electrical signals in neurons

A

Voltage changes across the membrane can be classifies in to 2 types of electrical signals:

60
Q

Two types of electrical signals

A

Graded proteins
Actions potentials

61
Q

Graded potentials

A

Variable strength signals that travel over short distances and lose strength as they travel. Can be depolarizing or hyper polarizing. If graded potentials create a large enough depolarization it can induce an Action Potential

62
Q

Action Potential

A

Very brief, large depolarizations that travel for long distanced through a neutron without losing strength. Rapid signals over ling distances

63
Q

Chanellopathies

A

Can disrupt how ions normally flow through the iron channel
Can alter channel activation
Can alter channel inactivation
Cystic fibrosis, congenital insensitivity to pain, muscle disorders

64
Q

Graded Potentials

A

Graded because amplitude (size) is directly proportional to the strength of the stimulus and can vary
Decrease in strength as they spread out from the point of origin
Generated by chemically gated (Ligand gated) ion channels (CNS and efferent neurons)
Chemical, mechanical, thermal gated in sentry neurons

65
Q

How do graded potentials lose strength

A

Current leak
Cytoplasmic resistance

66
Q

Current leak

A

open channels allow ions to leak out

67
Q

Depolarization

A

Excitatory Poatsynaptic Potential (EPSP)

68
Q

Hyperpolarization

A

Inhibitory Postsynaptic Potential (IPSP)

69
Q

Trigger Zone (Axon Hillock)

A

High concentration of voltage gated Na+ channels
If membrane potentials is 55mv an AP will be generated

70
Q

Action Potential (AP)

A

Electrical signals of uniform strength (Aloo or none) that travel from the trigger zone to the axon terminals

71
Q

Steps of Action Potential

A

Rising Phase
Falling phase
After Hyperpolarization phase

72
Q

Rising Phase (Depolarization)

A

Depolarizing stimuli open voltage gated Na+ Channels (-55mV), allow Na+ to travel down electrochemical gradient
At +30mV Na+ channels inactivate

73
Q

Falling phase (repolarization)

A

Voltage gated K+ also open in response to depolarization, but do so more slowly than Na+ change;s causing delayed efflux

74
Q

After Hyperpolarization phase (Undershoot)

A

Voltage gated K+ do not immediately close when reaching -70mV causing membrane potential to dip below the resting membrane potential
Leak channels bring membrane potential back to -70mV
Na-KATPase returns ions to original compartments (this does not need to happen before another AP can be triggered)

75
Q

Voltage Gated channels

A

The activation gate closes the channel at resting potential
Depolarizing stimulus arrives at the channel: Activation gate opens
With activation gate open, Na+ enters the cell
Inactivation gate closes and Na+ entry stops
During depolarization caused by K+ leaving the cell, the two gates reset to their original positions

76
Q

Absolute Refractory Period

A

A second AP cannot be initiated 1-2 sec

77
Q

Relative Refractory Period

A

A second AP can be initiated but requires a larger than normal depolarizing stimulus (Graded potential)
2-5msec

78
Q

What is purpose of Refractory Period

A

Ensures an AP travels in one direction
Limits the rate at which signals can be transmitted down a neutron
- Information is often encoded in the frequency of AP’S
- Prevent excitotoxicity

79
Q

Action potentials are conducted

A

AP’s travel over long distances without losing energy, a process referred to as conduction, size is identical at trigger zone and axon terminal

80
Q

Two parameters determine the velocity of action potentials in mammalian neurons

A

The diameter of the axon
The resistance of the axon membrane to ion leakage

81
Q

The diameter of Axon

A

A larger diameter axon will offer less internal resistance to current flow
- more ions will flow in a given time, bringing adjacent regions of the membrane to threshold faster

82
Q

The resistance of the axon membrane to ion leakage

A

Current will spread to adjacent sections more rapidly if it is not lost via leak channels (myelin)

83
Q

Conduction velocity is more rapidly in myelinated axon

A

AP conduction is more rapid in axons with high resistance membranes (decreased current leak)

84
Q

Myelinated axons

A

have larger diameter axons

85
Q

Unmyelinated axons

A

Have small diameter axons

86
Q

Demyelination

A
  • Only nodes contain Na+ channels, the AP cannot be maintained in the unmyelinated region due to a lack of Na+ channels
  • Current leaks out of the unmyelinated region, increasing the likelihood that the wave of depolarization is subthreshlod when it reaches the next node containing Na+ channels
87
Q

Normokalemia

A

When blood K+ is in the normal range
In normokalemia a suprathreshold (above threshold) stimulus will fire an action potential

88
Q

Hyperkalemia

A

increased blood K+ concentration, brings the membrane closer to a threshold. Now a stimulus that would normally be subthreshlod can trigger an action potential

89
Q

Hypokalemia

A

Decreased blood K+ concentration, hyper polarizes the membrane and. makes the neuron less likely to fire an action potential; in response to a stimulus that would normally be above the threshold

90
Q

How do neurons communicate

A

Presynaptic cell (Neuron) to postsynaptic cell (Neuron, muscle, target cell)

91
Q

Electrical synapses

A

Some CNS neurons, cardiac muscle, smooth muscle

92
Q

Chemical Synapses

A

The majority of neurons in the nervous system use chemical signals to communicate from one cell to the next

  • Electrical signals from the presynaptic cell is converted to a neurocrine signal that crosses the synaptic cleft and binds to a receptor on the post synaptic cell
93
Q

Neurocrine

A

A chemical substance released from neurons used for cell to cell communication

94
Q

Types of Neurocrines

A

Neurotransmitters
Neuromodulators
Neuroharmones

95
Q

Neurotransmitters

A

A chemical substance released, acts on a postsynaptic cell in close vicinity and causes a rapid response in the postsynaptic cell

96
Q

Neuromodulators

A

A chemical that is released, acts on a postsynaptic cell in close victim and causes a slow response in the postsynaptic cell

The same neurocrine can act as a neurotransmitter at one synapse and neuromodulator at another depending on the receptors present

97
Q

Neuroharmones

A

Are secreted into the blood stream and act on targets throughout the body

98
Q

Two categories of Neurocrine Receptors

A

Ionotropic receptors (ligand gated ion channels)
Metabotropic receptors (G- protein couples receptors)

99
Q

Ionotropic Receptors

A

Ligand gated ion channels
Ligand binding to inotropic receptors causes a conformational change leading to the opening of channel
Can be specific for one ion (Na+, Ca2+, K+,Cl- ) or a non selective cation Channel
Mediate fast postsyanptic responses (neurotransmitter)

100
Q

Metabotropic Receptors

A

G protein couples receptors
Slower responses (Neuromodulators)
Cytoplasmic tail of receptor is linked to three part membrane transducer protein (g-protein)
Ligand binding to metabotropic receptor leads to a G protein mediated cellular response

101
Q

Two types of Metabotropic Receptors

A

I. Interact directly with ion channels
ii. interaction with a membrane bound enzyme

102
Q

Interact directly with ion channels

A

Can lead to opening or closing of a channnel depending on G protein

103
Q

Interaction with a membrane bound enzyme. Two main types:

A

A. Phospholipase C Signal Transduction Pathway
B. Adenyl cyclase signal transduction pathway

104
Q

A. Phospholipase C Signal Transduction Pathway

A

Increase in intracellular Ca2+ mediates a cellular response
PKC can also mediate a cellular response

105
Q

B. Adenyl Cyclase signal transduction pathway

A

PKA phosphorylates proteins to cause a cellular response

106
Q

Fast responses are mediated by

A

Ion channels

107
Q

Slow responses are mediated by

A

G protein coupled receptors

108
Q

How does Neurotransmitter release occur

A

Occurs via Ca2+ mediated exocytosis
The pre synaptic terminal contains a high concentration of voltage gated Ca2+ channels

109
Q

Steps of Neurotransmitter release

A
  1. An action potential depolarizes the axon terminal
  2. The depolarization opens voltage gated Ca2+ channels, and Ca2+ enters the cell
  3. Calcium entry triggers exocytosis of synaptic synaptic vesicle contents
  4. Neurotransmitter diffuses across the synaptic cleft and binds with receptors on the postsynaptic cell
  5. Neurotransmitter binding initiates a response in the postsynaptic cell
110
Q

Termination of Neurotransmitter activity

A
  1. Neurotransmitters can be returned to axon terminals for reuse or transported into glial cells
  2. Enzymes inactivate neurotransmitters
  3. Neurotransmitters can diffuse out of the synaptic cleft
111
Q

What happens if there is a increased AP firing

A

Leads to the greater influx of Ca2+ and increased neurotransmitter release

112
Q

Convergence

A

Many presynaptic neurons may converge on one or a small number of postsynaptic neurons

113
Q

Divergence

A

Neurons can have branching axons that contact many different postsynaptic neurons

114
Q
A

BMSC 207 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions