Neurons and Glia Flashcards
1
Q
What is the organization of the CNS?
A
brain, spinal cord, and neural portions of the eye
2
Q
What is the organization of the PNS?
A
peripheral nerves, nerve endings, peripheral. nerve ganglia
3
Q
What is the similarity between the CNS and PNS?
A
both have neurons and glia/supporting cells
4
Q
What is the importance of glia?
A
needed for survival of neurons
5
Q
What are the cells in the brain?
A
neurons, glia, endothelial cell (brain capillary), and ependymal cells (epithelial-like)
6
Q
What are the types of glia?
A
astrocytes, oligodendrocytes, and microglia
7
Q
What are the components of the neurons in the CNS?
A
dendrites, axon, oligodendrocyte, node of ranvier, and nissl bodies
8
Q
What are the components of the neurons in the PNS?
A
schwann cells, myelin, motor and plate
9
Q
What type of cells contribute to myelination?
A
schwann cells
10
Q
What are the components of the cytoskeleton?
A
microtubules, centriole, actin (microfilament) and intermediate filaments
11
Q
What are the membrane bound organelles?
A
lysosome, vesicle, golgi, mitochondrion, S and R ER, and peroxisome
12
Q
What are the components of the nucleus?
A
nuclear membrane and nucleolus
13
Q
Nissl bodies and lipofuscin pigment make up the …?
A
neuronal cell body (soma)
14
Q
Ribosomes and rough ER make up what?
A
nissl bodies
15
Q
Lipofuscin pigment is also known as…
A
“age pigment”
16
Q
What is a lipofuscin pigment?
A
lysosomes with degradation products (residual body)
17
Q
Nissle bodies stain … with …. dye
A
dark; basic
18
Q
Dendrites are extensions of the …
A
cell soma; contains proteins and organelles
19
Q
Dendrites do what to the surface area of neurons for reception?
A
increase surface area
20
Q
Are dendrites myelinated?
A
NO
21
Q
What are the characteristics of dendrites?
A
many of them, ramified, spiny, taper as branch
22
Q
What are the characteristics of axons?
A
one, straight, NO spines, NO taper
23
Q
To conduct action potential is the purposed of what?
A
axons
24
Q
Do axons have nissl bodies or organelles?
A
NO
25
Can axons be myelinated?
YES
26
Bipolar, pseudounipolar, and multipolar are types of ....
neurons
27
What is a bipolar neuron?
single axon emerges from either side of the cell body
28
What is a pseudounipolar neuron?
single axon divides a short distance from the cell body
29
What is a multipolar neuron?
many dendrites and a single long axon emerge from the cell body
30
What are examples of a multipolar neuron?
pyramidal and purkinje cells
31
Neuron types are associated with what?
locations in the CNS or PNS
32
What are the unique properties of neurons?
1. conduct electrochemical signals after impulses are received on the dendrites or cell body
2. neurons possess unique connections between cells -> synapses
33
What is the direction of information flow in neurons?
dendrites -> soma -> axon -> synapse
34
Why are microtubules necessary?
important for neuron life
35
What are microtubules composed of?
tubulin proteins
36
Where are actin/microfilaments present?
in all cell types
37
What are actin/microfilaments composed of?
G (globular) and F (filamentous) actin
38
What is G actin?
free actin in cytoplasm
39
What is F actin?
polymerized actin of the filament
40
Which end of F actin fast growing?
plus end
41
Which end of F actin slow growing?
minus
42
What do actin/microfilaments aid with within the cell?
transport
43
What are the diameters of the parts of the cytoskeleton?
microtubules: 25 nm
actin/microfilaments: 5 nm
intermediate: 10 nm
44
What are intermediate filaments composed of?
neurofilament (light, medium, heavy)
45
What are intermediate filaments used for?
identification of tissues
46
What are the characteristics of intermediate filaments?
rope-like; heterogenous protein family (6 classes)
47
What is apart of class 3 family for intermediate filaments?
vimentin (most distributed IF tissue)
48
Vimentin is composed of ....
1. glial acidic fibrillry protein -> astrocytes
2. peripherin (peripheral nerve cells)
49
What is apart of class 4 family for intermediate filaments?
neurofilaments and nestin (nerve cells)
50
What are neurofilaments and where are they found?
neurofilament triplet proteins (L,H,M); in axons and dendrites of nerve cells
51
What is nestin and where can it be found?
neural stem cells; muscle cells
52
What are the two motor proteins?
kinesin and dynein
53
What type of transport does kinesin mediate?
anterograde: AWAY from the cell
54
What type of transport does dynein mediate?
retrograde: TOWARDS the cell/centrosome
55
What is the transport of neurotransmitter and their precursors?
anterograde
56
Which motor protein plays a role in ciliary and flagellar movement?
dynein
57
In axonal transport, where does anterograde travel? Fast or slow?
from soma to synapse; FAST
58
In axonal transport, where does retrograde travel? Fast or slow?
from synapse to soma; SLOW
59
Which axonal transport serves as a potential entry for harmful substances from periphery to neuronal cell body?
retrograde
60
What is the path of kinesin transport?
1. organelles/vesicles attach to kinesin
2. microtubule releases ADP
3. kinesin moves along microtubule using ATP
61
What is the path of dynein transport?
1. organelles/vesicles attach to dynein
2. dynein moves along microtubule using ATP
3. ADP is released
62
What are the types of synapses?
axosomatic, axoaxonic, axodendritic, and axospinous
63
What is an axosomatic synapse?
an axon terminal ending on the soma of a neuron
64
Which synapse is: an axon terminal contacting another axon terminal?
axoaxonic
65
Which synapse is: an axon terminal ending on a dendrite?
axodendritic synapse
66
What is an axospinous synapse?
an axon terminal facing a dendritic spine
67
Bergman glia allows for...
migration of neurons
68
What is Bergman glia?
functional interdependence of neuroglial cells and neurons during development
69
What are the types of astrocytes?
protoplasmic and fibrous
70
Where are protoplasmic astrocytes found?
in gray matter
71
What astrocyte is found in white matter?
fibrous
72
What glial cell is involved in myelination in the CNS?
oligodendrocytes
73
Where can oligodendrocytes be found?
in white matter; found in gray but role unknown
74
What is the function of astrocytes?
1. nourishment of neurons
2.maintenance of neurons
3. protection of neurons
75
Astrocytes serve as what type of barrier?
blood-brain barrier
76
What is the only reservoir of glycogen in the brain?
astrocytes
77
What glial cell serves as an index of CNS toxicity?
astrocytes
78
How do astrocytes interconnect and outline the CNS?
1. brain surface
2. ependymal lining of ventricles
3. synapses and blood vessels
4. isolate synapses and nodes of ranvier
5. surround foreign bodies in CNS
6. form "glial scar" with high conc. of GFAP fibrils
79
How do astrocytes react to injury?
by increasing GFAP
80
Astrocytes form what type of junctions to permit cell transfer of small molecules/ions?
desmosomal (tight) and gap
81
Why do astrocytes form syncytium junctions?
allow diffusion of ions/small cytoplasmic molecules between adjacent astrocytes
82
What is the name of the gap junction protein?
connexin-43
83
What is the microglia life cycle?
1. enter CNS and become ameboid microglia to clear debris during development
2. blood-brain barrier closes; becomes quiescent microglia
3. activated by injury/infection
84
What cells are the resident macrophages of the CNS?
phagocytic cells
85
What type of glia is the primary responder to injury of the brain?
microglia
86
What are examples of injuries microglia can respond to?
multiple sclerosis and trauma
87
What are the 2 markers of microglia?
complement receptor 3 and MHC-2
88
Microglial cells and astrocytes interact to modulate what?
immune responses
89
How does microglia react to CNS injury?
1. after damage. become progressively activated
2. severe activation causes macrophages to form
3. inflammation can lead to damage of neurons
90
Myelin sheaths are synthesized by what?
oligodendrocytes
91
Oligodendrocytes can myelinate how many axons?
SEVERAL
92
What is the role of oligodendrocytes?
1. wrap around axons of CNS neurons
2. insulate axon and enhance speed of conduction of electrochemical impulses
93
How do Schwann cells play a role in the myelination process?
wraps around ONE axon
94
Schwann cells form....
myelin sheaths
95
Stimuli from multiple synapses sum at the...
axon hillock
96
What happens when a threshold is reached during impulse conduction?
an action potential (wave) is triggered
97
Where does the action potential (wave) travel?
DOWN the axon
98
What does the speed of the action potential depend on?
the diameter of the axon
99
What is saltatory conduction?
when nerve impulses "jump" from node to node
100
What are non-brain fenestrated capillaries?
have SMALL GAPS in plasma membrane of endothelial cells
101
What are brain non-fenestrated capillaries?
have TIGHT junctions between endothelial cells
102
How is the blood-brain barrier formed?
by endothelial cells with tight junctions and glial feet processed of astrocytes
103
Why do astrocytes induce capillaries?
to form zonula occludens to limit diffusion of small molecules
104
Ependymal cells line what surface?
inner surface of brain ventricles
105
What are the functions of ependymal?
1. movement of CSF
2. bidirectional transport of materials between CSF and neuropil
106
Where can ependymal cells be modified within to produce CSF (part of choroid plexus)?
ventricles
107
What makes up the volume of the brain?
half is neurons; Other half is neuroglia/glia
