Nervous System Flashcards
(114 cards)
1
Q
What does the nervous system look like?
A
a network
2
Q
What are the two functions of the nervous system?
A
communication and control
3
Q
What are the nervous system processes?
A
- collects information
- processes information
- Initiates response
4
Q
The nervous system uses what to collect information?
A
receptors
5
Q
Where does the nervous system process information?
A
in the control center
6
Q
Where are responses/commands sent in the nervous system?
A
to the effectors
7
Q
What are the only kinds of effectors?
A
muscles and glands
8
Q
What is the organization of the nervous system?
A
the central and peripheral nervous system
9
Q
What is the function of the central nervous system?
A
process information
10
Q
What components make up the central nervous system?
A
the brain and spinal cord
11
Q
What is the function of the peripheral nervous system?
A
transmit information
12
Q
What are the components of the peripheral nervous system?
A
nerves and ganglia
13
Q
What kind of nerves come from the peripheral nervous
system?
A
sensory and motor nerves
14
Q
What are the two types of cells in the nervous system?
A
neurons and glial
15
Q
Neurons
A
- basic functional units of the nervous system
- excitable calls that transmit signals
16
Q
Glial
A
non-excitable cells
17
Q
Glial functions
A
protect and support neurons
18
Q
Neurons have extreme longevity but are what kinds of cells?
A
amitotic
19
Q
Amitotic
A
lost the ability to divide
20
Q
Nerves
A
bundles of neurons
21
Q
Ganglia
A
cluster of neuron bodies
22
Q
What glial cells are in the central nervous system?
A
- astrocytes
- ependymal
- microglia
- oligodendrocytes
23
Q
Astrocytes
A
star-shaped cells that connect capillary walls with neurons
24
Q
Astrocytes functions
A
- establish blood-brain barrier
- form supporting networks
- assist neuronal development and repair processes
- communicate with neurons and adjust their activities
25
Ependymal cells
- ciliated epithelial cell that line internal cavities
26
Ependymal cell function
involved in the production and movement of cerebrospinal fluid (CSF)
27
Microglia
small cells with slender branches that wander the CNS
28
Microglia function
phagocytize (engulf) infectious agents and debris
29
Oligodendrocytes
large cells with slender extensions that wrap around the axons
30
Oligodendrocyte function
insulation of axons in a myelin sheath that speeds up the movement of signals
31
What cells are in the peripheral nervous system?
satellite cells and neurolemmocytes
32
Satellite cells
surround neuronal cell bodies in a ganglion
33
Satellite cell functions
regulate the exchange of nutrients and waste products
34
Neurolemmocytes (Schwann cells)
wrap around axons to form myelin sheath for faster signal propagation
35
Myelination
is the process by which parts of an axon become wrapped in the myelin sheaths composed of repeating layers if glial cell plasma membrane with proportions of lipids.
36
The lipids in myelin sheath does what?
gives glossy white appearance and insulates axon
37
Myelinated axons perform what?
saltatory conduction
38
Saltatory conduction
nerve impulse/signal skips myelinated areas
39
Myelinated axon nerve impulses speed up to what?
150 m/c
40
Unmyelinated axons transmit nerve impulse through what process?
continuous conduction
41
Unmyelinated axon nerve impulses speed up to what?
2 m/c
42
What are the three parts of a neuron?
- dendrites
- body
- axon
43
Dendrites
short branches attached to the body
44
Dendrites functions
membrane receives stimuli
45
Body =
soma
46
Body characteristics
- unnucleated
- many ribosomes (gray)
47
Body function
membrane receives stimuli
48
Axon characteristics
- long branch
- axon hillock
- axon terminals
49
Axon fucntion
passes signals to nervous system, muscular system, or glands
50
Axon: nerve
a bundle of axons enclosed in 3 layers of CT:
- endoneurium
- perineurium
- epineurium
51
What are the two neuron classifications?
structural and functional
52
What are the four structural classifications of a neuron?
- multipolar
- bipolar
- unipolar
- anaxonic
53
What are the three functional classifications of a neuron?
- sensory
- motor
- interneurons
54
Sensory neuron pathway
receptors to CNS
55
Motor neuron pathway
CNS to effectors
56
What is another name for sensory neurons?
afferent
57
What is another name for motor neurons?
efferent
58
What is another name for interneurons?
association
59
What are neuron membranes capable of?
initiating, processing, and transmitting signals
60
What is the resting membrane potential of neurons?
-70 mV
61
What three channels are responsible for the RMP of neurons?
- Na-K pump
- K+ channels
- Na+ leak channel
62
The Na+ leak channel is only present in what kind of structure?
neurons
63
Depolarization
cell with a less negative charge than the outside
64
Hyperpolarization
cell with a more negative charge than the outside
65
What are the properties of a neuron?
- lipid bilayer +( lipid and carb)
- semi-permeable
- at rest the membrane is polarized = -70mV
- Concentration gradient for Na+, Cl-, and K+
- neurons use their membranes to establish synapses
66
What happens if gated ion channels open?
ions diffuse (H to L) causes intentionally altered RMP
67
What happens when Na+ channels open?
- sodium diffuses in
- the cell becomes less negative causing depolarization
68
What happens when K+ channels open?
- potassium diffuses out
- the cell becomes more negative causing hyperpolarization
69
What happens when Cl- channels open?
- chloride diffuses in
- the cell becomes more negative causing hyperpolarization
70
Synapse
is a site across the which neuron passes a signal to another neuron, muscle cell, or gland cell
71
What are the characteristics of a chemical synapse?
- uses neurotransmitters
- slow but common
- may excite or inhibit the postsynaptic cell
72
What are neurotransmitters?
organic compounds (=100) produced by neurons in order to transmit a signal
73
What are two types of neurotransmitters?
acetylcholine and norepinephrine
74
Acetylcholine effect
- excites skeletal muscles
- inhibits cardiac muscle
75
Norepinephrine effect
- excites cardiac muscle
- inhibits digestive system
76
What are the two methods used in the elimination of the neurotransmitter?
Degradation and reuptake
77
Degradation is done by what?
enzymes
78
Reuptake is done by what?
transporters
79
What are the 4 functional segments of a neuron?
- receptive
- initial
- conductive
- transmissive
80
Receptive: part of neuron
dendrites and cell body
81
Initial: part of neuron
axon hillock
82
Conductive: part of neuron
axon and terminals
83
Transmissive: part of neuron
synaptic knobs
84
Receptive: function
receives stimuli (input)
85
Initial: function
action potential may be initiated
86
Conductive: function
conducts action potential
87
What is another word for conducts?
propagates
88
Transmissive: function
neurotransmitter excites or inhibits a postsynaptic cell
89
What is the most common stimulus?
neurotransmitters released from another neuron
90
What events occur in response to neurotransmitters release?
- NT binds to the specific receptor
- chemically gated ion channels open temporarily
- ions diffuse (H to L)
- RMP is slightly altered
91
Graded potential
a small, short- lived deviation from RMP
92
What happens to the membrane during graded potential?
membrane becomes slightly depolarized or hyperpolarized
93
The degree or grade of graded potential is dependent on what?
the strength of the stimulation
94
What is another name for graded potential?
postsynaptic potential
95
What are the two kinds of postsynaptic potential?
EPSP and IPSP
96
Excitatory PSP
- a neurotransmitter opens a Na+ channel
- Causes slight depolarization
- closer to the threshold
97
Inhibitory PSP
- a neurotransmitter opens K+ and Cl- channel
- causes slight hyperpolarization
- away from the threshold
98
Where are EPSPs and IPSPs generated?
receptive segment
99
Where does summation/processing of EPSPs and IPSPs happen?
Initial segment
100
What law does summation follow?
all or none law
101
What happens if numerous excitatory stimuli arrive to the receptive segment?
- large amount of Na+ enters the cytoplasm and reach the axon hillock
102
What happens if the threshold is reached in the axon hillock?
voltage-gated channels are triggered to open in the axon hillock
103
What is initiated in the initial segment?
action potential
104
What happens if the threshold is not reached?
no action potential
105
What happens in once action potential is initiated?
once initiated, action potential needs to be conduction (propagation) along the axon.
106
What happens in the conductive segment?
axon membrane undergoes a wave of depolarization, followed by repolarization.
107
What is the goal of depolarization?
to spread the action potential
108
What structure does depolarization?
voltage-gated Na+ channel
109
What is the value of action potential?
+30 mV
110
Nerve impulse
the consecutive opening of voltage gated Na+ channels
111
What is the goal of repolarization?
to return the membrane to RMP after the AP passes
112
Repolarization is done by what structure?
voltage-gated K+ channels
113
What is the process of repolarization?
- threshold is reached -55mV
- voltage-gated K+ channels open slowly
- K+ diffuses out
- membrane becomes more negative
- channels close too slowly
- membrane becomes hyperpolarized
- RMP is reestablished by Na+/K+ pumps
114
What happens when AP arrives to the synaptic knob?
- voltage-gated Ca2+ channels open
- Ca2+ diffuses in
- synaptic vesicles release neurotransmitter into the synaptic cleft
- neurotransmitter diffuses and binds to the receptors on the postsynaptic cell
- postsynaptic cell is activated or inhibited
