Neurons: Lec 2 Flashcards
(135 cards)
1
Q
Neurons
A
information processors
2
Q
Glial Cells
A
Scaffolding and support services and communication facilitators
3
Q
Anatomy of a neuron
A
Cell body/ soma/ perikaryon
Dendrites
Axon
4
Q
components of the cell body/soma/perikaryon
A
nucleus, organelles, mitochondria, golgi apparatus, cytoskeleton, microtubules, neurofiliments
5
Q
components of the dendrites
A
dendritic tree
dendritic spines
6
Q
components of the axon
A
axon hillock
initial segment
node of ranvier
terminal button
7
Q
Oligodendrocytes are myelin cell for what system
A
central nervous system
8
Q
oligodendrocytes are multiple axons to 1 what
A
cell
9
Q
Schwann cells are myelin cells for what system
A
PNS
10
Q
schwann cells are multiple cells to 1 what
A
axon
11
Q
schwann cells are speed what?
A
synaptic transmission
12
Q
types of glial cells
A
oligodendrocytes
schwann cells
astrocytes
13
Q
Astrocytes
A
star shaped cytoskeletal cells
14
Q
three types of astrocytes
A
Protoplasmic
fibrous
radial
15
Q
what are protoplasmic astrocytes
A
gray matter
16
Q
what are fibrous astrocytes
A
white matter
17
Q
what are radial astrocytes
A
development guide cells
18
Q
Roles of the astrocytes
A
- structural support
- Blood brain barrier
- scar formation
- nutrient transport
- release glutamate (neurotransmitter)
19
Q
unipolar
A
one cell process
20
Q
example of unipolar cells
A
spinal ganglia
21
Q
Bipolar
A
two cell processes
22
Q
functions of bipolar
A
sensory
23
Q
example where bipolar cells are
A
retina
24
Q
Multipolar
A
> 2 dendrites. many dendrites and 1 axon
25
Multipolar transmit what
sensory and motor
26
What systems are mostly composed of multipolar cells
CNS & PNS
27
pseudounipolar
afferent and efferent
28
afferent
takes info from environment to CNS
29
Efferent
takes information from CNS to muscles, glands
30
Ganglion/ ganglia
collection of cell bodies
31
Projection fibers
axon that travel up and down the CNS
32
Association fibers
axon that connect one lobe to another
33
commissural fibers
axon running between the hemispheres
34
Internuncial neurons
transmit AP from one neuron to another
35
Gray Matter
collections of nerve cell bodies
unmylinated fibers
dendtries found in CNS
36
white matter
collections of mylinated fibers
37
Fasiculas
small bundle of myelinated fibers
38
Fasiculas is synonym for what
tract in certain spinal cord sections
39
funiculus
"a little cord" composed of several fasiculi
40
funiculus differentiate what
dorsal, lateral and ventral funiculi
41
Brachium
"arm" thick bundle of fibers connecting one part of the brain to the other
42
what are synaptic triggers of action potential
- mechanical
- thermal
- chemical
- light
- electrical
43
the 3 things of a basic synaptic transmission
1. stimulus causes change in electrical potential of cell
2. threshold is reached and AP travel down axon
3. Terminal endings release chemicals that cause depolarization of next dendritic tree or cell body
44
Axon hill is the what of transmissions
gatekeeper
45
All or none phenomena
once AP fires, it is equal throughout length of axon
46
myelinated axons transmitted what than non myelinated
faster
47
fatter or skinner axons are faster?
fatter
48
voltage sensitive channels collect where
nodes of ranvier
49
voltage sensitive channels collect at nodes of ranvier, facilitating what?
saltatory conduction
50
Electrical potential as the basis for what?
synaptic transmission
51
at resting potential the cell membrane is what ?
semipermeable
52
synaptic/ receptor potentials are small areas of
depolarization
53
Depolarization
> 15 mV change required causing a rush of Na+ into channels
54
Action potential propagation continues until when
all channels are opened (cell becomes -50mV)
55
when does repolarization happen?
resting potential is reestablished
56
what is not possible during repolarization?
action potential
57
Characteristics of ion channels in cell membranes
multiple states
gating
selectivity for types and sizes of ions
58
at multiple states channels can be
either open or closed
59
voltage gate channels respond to
voltage changes
60
ligand gated channels respond to
signal molecules that land on binding sites
61
thermal gated channels respond to
temperature changes
62
mechanically gated channels respond to
deformation
63
selectivity for types and sizes of ions depend on what/
size of channel and type of molecular lining
64
absolute refractory period
intracellular charge reaches +30 - +50 mV and all Na+ channels are closed. No AP possible during this time
65
Relative refractory Period
both Na+ and K+ channels are closed causing hyper polarization .
66
During relative refractory period was cause a AP
MORE stimulus
67
Factors that affect transmission speed
- myelination
- axon diameter (larger faster)
- temp of limb (cold slow)
- age (>4 - faster)
- disease (demyelinating slow)
68
amines
small molecules / neurotransmitters
69
examples of amines
acetylcholine, catecholamines (dopamine, norepinphrine) serotonin, histamine
70
Amino acids
1-10 amines
71
examples of amino acids
glutamate, GABA, Glycine
72
Neuropeptides
large amino acid clusters
73
examples of neuropeptides
angiotensin II, B-endorphin, Cholecystokinin, corticotropin releasing factor, substance P, Enkephalin
74
Amines are creased in
presynaptic cytoplasm
75
Peptides are created in
cell body
76
Nicotinic receptors on the cell yield excitatory effect in
response to acetylcholine
77
Muscarinic receptors yield inhibitory effect in ?
response to acetylcholine
78
Acetylcholine can be what depending on the receptors
-Excitatory or inhibitory
79
Acetylcholine on skeletal muscles has what effect
excitatory
80
Acetylcholine on smooth and cardiac muscle has what effect
inhibitory
81
neurons communicate by what
chemical transmitters that cause electrical potentials
82
When does the nervous system begin to evolve
week 3
83
when does the bilaminar disc form from which nervous system will form?
14 days
84
When is their implantation ?
week 2
85
when is there further development of you sac,amnion and embryonic disc?
week 2
86
Primitive streak and groove appear where and when
in the ectoderm and week 3
87
when is there neural tube formation ?
week 3
88
Neural crest become
sensory & ANS ganglia
| glands
89
Neural tube becomes
CNS, epidermis, tooth enamel
90
Notochord becomes
nucleus propulsus
91
Dermatome becomes
subcutaneous skin, sensory
92
Myotome becomes
dorsal spinal muscles
93
Sclerotome becomes
vertebral column & ribs
94
when does neural tube folding begin
week 4
95
What are the Neural tube layers
- epitheial layer
- Mantle layer
- Marginal layer
- Dorsal/alar plate
- ventral/ basal plate
- Intermediare zone
96
Gliablasts or spongioblasts (epithelial layer) becomes
- ependymal cells
- astrocytes
- oligodendrocytes
97
mantle layer becomes
gray matter
98
mantle layer sends what
neuronal process outward
99
marginal layer becomes
white matter following myelination
100
What functions does the dorsal / alar plate have
sensory
101
what functions does the ventral/ basal plate have
motor
102
What functions does the intermediate zone have
autonomic
103
what happens at week 5
cephalic folds
| limbs buds appear
104
what happens at week 6
Eye
| UE elbow-hand
105
What happens at week 7
acoustic meat
UE digits
foot plate
106
Prosencephalon split into
telencephalon & diencephalon
107
Telencephalon becomes what
cerebral hemispheres, corpus striatum, cortex + medullary center of white matter
108
Diencephalon becomes what
thalamus, epithalamus, hypothalamus and sub thalamus
109
Mesencephalon becomes
midbrain
110
Rhombencephalon divides into
metencephalon & Myelencephalon
111
Metencephalon becomes
pon & cerebellum
112
Myelencephalon becomes
Medulla oblongata
113
What happens at week 8?
facial features begin to form, UE and LE joints and digits have differentiated.
abdominal cavity is not complete
tail is not obvious
114
week 9-38 are considered
fetal period
115
When is a baby most vulnerable to teratogenic influences
first 2 months
116
Anencephaly
rostral neuropore does not close in 4th week
117
Spina bifida occulta
caudal neuropore does not close in 4th week, vertebral arches do not fuse
118
Meningocele
dural sack extrudes but no spinal nerve included
119
Meningomyelocele
portions of spinal cord displaced into extruding dural sack
120
Cleft palate
lack of midline closure during 6-12 weeks
121
plagiocephaly
asymmetrical skull shape
122
Brachycephaly
when baby lays on back all the time
123
Neonatal Neuronal Exuberance
- greater # of neurons are created than needed
- duplication of synaptic pathways is plentiful during development
- Synaptic connections multiply quickly
- selected cells become dormant if not used
124
Neurotophism
changes occur from the interaction of synaptically connected cells
125
during neurotophism what happens to dendrites, axon and synaptic vessel
dendritic spine proliferation
axonal myelination
synaptic vesicle development
126
What happens when neurons do not get stimulation
degrad, die or go dormant
127
What happens to cells that do not connect with enough other cells
do not receive the neurotrophic stimuli to mature
128
paring in the NS may help what
streamline communication
129
Dormant cell may be used at a later time if what happens
stimulation
130
What is neural plasticity
ability of CNS to create new pathways
131
what increases synaptic activity in the cortex and in periphery
practicing a skill
132
During an injury, what takes over for damaged tissue
adjacent cortical tissue
133
During injury, what is done to accomplish the same functional result
development of new pathways
134
what excites neurons
stimulation
135
what is related to pruning
lack of excitation
