Week 1 - Study Guide Flashcards
1
Q
Identify three types of neurons of the Nervous System
A
Afferent - PNS
Efferent - PNS
Interneurons - CNS
2
Q
What type of neuron are sensory neurons
A
Afferent
3
Q
What type of neurons are motor commands
A
Efferent
4
Q
What are the two types of neurons in the PNS
A
Afferent
Efferent
5
Q
What is the neuron that is in the CNS
A
Interneuron
6
Q
What is Afferent neurons role?
A
*Sensory
*Receive Incoming information
*Internal & External
*needs to be processed at the brain
7
Q
What is Efferent neurons role?
A
*Send out motor commands
*Action Potential -motor output
* Effector organs
8
Q
What is Interneuron/Association neurons role?
A
- Connection
- Integration
- Make sense of information going to the brain
9
Q
Reflexes use…
A
excitatory and inhibitory
10
Q
Divisions of the NS
A
CNS
PNS
11
Q
Role of the CNS
A
Integrative Control Center
12
Q
Where is the CNS located?
A
Brain and Spinal Cord
13
Q
Where is the PNS located?
A
Everything else except the brain and spinal cord
14
Q
What are the divisions of the PNS
A
Afferent Division
Efferent Division
15
Q
What are the branches of the Efferent Division
A
Somatic NS
ANS
16
Q
What are the branches of the ANS
A
Sympathetic NS - fight or flight
Parasympathetic NS - rest & digest
17
Q
Afferent division of PNS
A
- Sensory
- Pathway bringing info to CNS
18
Q
Efferent division of PNS
A
- Motor
- sending commands to peripheral structures
19
Q
Somatic NS role
A
Voluntary motor output
Reflexes
Skeletal muscle
20
Q
Autonomic NS role
A
involuntary motor output
21
Q
Two cell types
A
Neurons
Neuroglia
22
Q
What are neurons
A
excitable cells
sensory & afferent
23
Q
What are neuroglia cells
A
Supporting cells
24
Q
4 types of neuroglia cells
A
- astrocytes
- Ependymal cells
- Oligodendrocytes
- Schwann cells
25
Which type of Neuroglia cells belongs to the PNS
Schwann cells
26
Special characteristics of Neurons?
1. Long-lived
2. Amitotic - no cell division
3. high metabolic rate
4. Plasma membrane function
27
What are the basic parts of the neuron?
1. Dendrites
2. Cell body
3. Axon Hillock
4. Axon
5. Myelin Sheath
28
What part of the neuron integrates information?
cell body
29
What parts of the neurons do incoming signals come into?
Dendrites & cell body
30
Where does the action potential travel
Axon
31
What is the long extension out from the cell body to the next cell
Axon
32
Cell that creates myelin in CNS only
Oligodendrocytes
Only part of it wraps around an axon
33
What is a feature unique to Schwann cells?
Neurilemma - a bump as you roll Myelin - think pigs in a blanket
34
Nodes of Ranvier
Myelin Sheath gaps in between Schwann cells
35
What ions are at the Nodes of Ranvier?
Na+ & K+
36
Saltatory Conduction
Jumps from Node to Node for faster signaling
37
What are the most abundant glial cells in the CNS
Astrocytes
38
What do astrocytes do?
1. BBB
2. Control Chemical environment
3. form tight junctions
39
Neurons role
Signaling system in and out
40
Ependymal Cells role
1. Lining cavities of CNS
2. Cilia moves CSF past stationary cells
41
What cells belong to the PNS?
Neurons
Schwann cells
42
What cells belong to the CNS
Epyndemal cells
Neurons
Astrocytes
Oligodendrocytes
43
What cells belong to both PNS and CNS
Neurons
44
Schwann Cells role
Speed signal travel
45
Oligodendrocyte role
Speed Signal travel
46
What is the difference between Oligodendrocyte and Schwann cells
1. Oligodendrocytes only wrap myelin around part of the axon
2. Oligodendrocytes do not have a neurilemma - bump
47
Permeability
Whether or not it can get across the membrane
48
Resting membrane potential
-70mV
* more Na+ and Cl- ions outside the cell
* more K+ and anionic proteins in the cell
49
How is resting membrane potential maintained?
Na+/K+ pump
50
What is threshold
-55mV
51
What is the location where an threshold needs to be met before an action potential happens?
Axon Hillock
52
Changing membrane potential - DEPOLARIZATION
1. Becomes less negative
2. increase likelihood of AP
3. positive ions enter cell bringing closer to threshold -55mV
53
Changing membrane potential - HYPERPOLARIZATION
1. Becomes more negative
2. decrease likelihood of AP
3. getting further away from baseline of -70mV
54
Changing membrane potential - ACTION POTENTIAL
1. stimulus
2. threshold met -55mV
3. NA+ channels open
4. Spike to +30mV - Depolarization occurs
5. Na+ close
6. K+ channels open
7. Repolarization occurs
8. Back to baseline -70mV
9. Hyperpolarization occurs
10. Na+/K+ pumps bring back to baseline -70mV
which resets to resting membrane
55
Two main types of ion channels
Leak channels
Gated Channels
56
Three types of gated channels
1. Chemically gated
2. Voltage gated
3. Mechanically gated (auditory example)
57
How to open a chemical gate
1. Chemical has to bind to receptor to open gate
2. Specificity - one shape one job
58
How to open a Voltage-gated channel
If Na+ rushes in -
Changes the voltage
Na+ channels open on the axon where voltage change occurs
59
What are two types of signals
1. Graded Potential
2. Action Potential
60
Describe Action Potentials and location
1. Outgoing signals down the axon
2. maintains signal whole time - on/off
3. long distance signals of axons
4. Voltage change -70mV to +30mV
5. occurs in nerves and muscles
61
Describe Graded Potentials and location
1. found on cell body and dendrites
2. incoming short signals
3. Spread and lose signal strength
4. They travel to the Axon Hillock
5. Need significant strength to make threshold at axon hillock -55mV
62
Which gate is fast?
Sodium
63
Which gate is slow?
Potassium
64
What ions are critical in NS transmissions?
Na
K
Ca
65
What triggers neurotransmitter release?
Calcium influx
66
Electrical Synapses
1. less common
2. Gap Junctions in Heart and developmental
3. Communication is very rapid
4. important in embryonic nervous tissue and some brain regions
67
Chemical Synapses
1. Direct relationship between 1st and 2nd cell - 2. Presynaptic neurons release neurotransmitter
3. postsynaptic have receptors specific to neurotransmitter
68
Two types of Graded POSTSYNAPTIC potentials
EPSP. (Na+. K+)
IPSP. (K+. Cl-)
69
A single EPSP cannot...
1. induce an action potential
2. EPSP required to add together - SUMMATE - in order to illicit an AP
70
EPSP causes
1. Depolarization =
Na+ influx --> K+ efflux
2. Na and K flow in opposite direction
71
IPSP causes
1. Hyperpolarization
2. Opens channels for K+ and Cl-
3. inhibits
72
What ions and what direction do they move in EPSP?
1. Na+ = travels into neuron
2. K+ =travels out of neuron
73
What ions and what direction do they move in IPSP?
1. K+ = leaves the neuron
2. Cl- = enters the neuron
74
How do EPSPs reach threshold?
Summation
75
Temporal Summation
1. one or more presynaptic neuron transmit rapid impulses
2. Repeated fire close in time
3. Single cell fire rapidly
4. Cells fire together repeatedly
76
Spatial Summation
2 different locations fire at the same time
77
What are forms of membrane channels found on neurons or in the nervous system
Leak channels
Gated Channels
78
How do we code signal intensity in the nervous system?
The CNS determines stimulus intensity by the frequency of impulses.
How many AP did you send? 1 or 100
79
How do we slow the signal travel in the neuron?
1. Non-myelination
2. Smaller diameter of axon
80
How do we speed the signal travel in the neuron?
1. Myelination
2. Thicker diameter of axon and myelin sheath
81
What is Saltatory Conduction?
1. AP signal jumps from node to node
2. Myelin sheath on axon
3. Voltage gate Na+ channels only located at the nodes
4. A pattern of conduction when myelinated and is 30x faster
5. Faster process
82
What is Continuous Conduction?
1. Non-myelinated axons
2. slower process
3. Have voltage channels that are evenly spaced
83
Absolute Refractory Period
1. Initial part of sending AP now
2. First phase from depolarization to repolarization
3. from opening of Na+ channels
4. closing of Na+ channels
5. Opening of K+ channels
6. K+ leaves
7. One way transmission
8. AP is all or. nothing event
Period of repolarization of the neurons during which it cannot respond to a second stimulus
84
What is Refractory period?
1. Phase immediately following Absolute refractory period
2. Repolarization is occurring
3. K+ channels finishing up
4. Repolarization phase
5. Goes into Hyperpolarization
6. Na+ / K+ pumps kick in to reset te resting membrane potential
7. Threshold for AP generation is elevated
8. Exceptionally strong stimulus may generate an AP
85
Why do Absolute refractory period and relative refractory period matter in the NS?
They wouldn't be able to return to its resting membrane potential & generate new impulse
86
What ion is the chief intracellular ion in a resting neuron?
Potassium
87
Depolarization is --
State in which resting membrane potential is reversed as sodium ions rush in to the neuron
88
Absolute refractory period is --
the period of repolarization of the neurons during which it cannot respond to a second stimulus
89
Na+ / K+ pump is a process --
by which ATP is used to move 3 Na+ ions out and 2 K+ ions in the cell to restore resting membrane potential
90
Direct Action - Relationship
1. Chemical released
2. need receptor to bind
3. gates open ion channels
Example - Neuromuscular Junction
91
What happens during Direct Action?
1. Binds to gate - gate opens
2. Promotes rapid response
3. Polarization change
92
Indirect Action - Relationship
1. Chemical released
2. Receptor only activates if NT binds
3. causes an action @ enzyme
4. either - excitatory or inhibitory
Not a guaranteed pattern
Case study TTX- Tetanus - goes after Na+ channels
Promotes long-lasting effects
93
What happens during Indirect Action?
1. Neurotransmitter binds to receptor
2. Activated by G proteins
3. 2nd messengers
4. complex
94
Diverging Circuit
Common in Sensory and Motor Systems
1. One to Many
2. signal out - better processing
95
Converging Circuit
Common in Sensory and Motor Systems
1. Many to One
96
Reciprocal Inhibition
REFLEXES
Excite one / inhibit another
