intro to nervous Flashcards
(70 cards)
1
Q
mostly formed by nerve cell bodies, supporting
cells (neuroglia), and nonmyelinated fibers.
A
Gray matter:
2
Q
basically formed by myelinated fibers and supporting cells (neuroglia)
A
White matter
3
Q
nerve cell bodies within CNS
A
Nucleus
thalmus-gigantic nucleus
4
Q
nerve cell bodies outside CNS
A
Ganglion
5
Q
3 Main Functions of the Nervous System
A
1. sensing changes; done by sensory (afferent) neurons 2. interpreting and remembering those changes; done by association or interneurons 3. reacting to those changes done by efferent neurons
6
Q
single nucleus with prominent
nucleolus
A
Cell body-perikaryon
-nucleolus-produce ribosomal subunits
7
Q
chromatophilic
substance
A
Nissl Bodies- no other cell
8
Q
Cell body (protein synthesis)
A
rough ER & free ribosomes
9
Q
cell body( give cell shape and support)
A
neurofilaments
10
Q
move material inside cell (cell body)
A
microtubules
fun fact: one of the reason alzheimers entanglement of microtubules within cytoplasm- nerve conduction stops-memory ( loosing memory)
11
Q
indigestable material within the neurons harmless aging(cell body)
A
lipofuscin pigment clumps
- occupying the space in the cytoplasm-gradually slow down the function
- part of the brain most vulnearable- aging happen
12
Q
Cell processes
A
dendrites; axons
13
Q
Conducts impulses towards the cell body Typically short and highly branched. Surfaces specialized for contact with other neurons Contains neurofibrils & Nissl bodies
A
Dendrites-towards the cell body
14
Q
Conduct impulses away from cell body Long, thin cylindrical process of cell Arises at axon hillock Impulses arise from initial segment (trigger zone) -Swollen tips called synaptic end bulbs contain vesicles filled with neurotransmiLers
A
Axon-away from cell body
15
Q
Side branches (collaterals) end in fine processes
A
axon terminals
16
Q
several dendrites & one axon
most common cell type
A
Multipolar-star shaped
17
Q
one main dendrite & one axon
found in retina, inner ear & olfactory
A
Bipolar
18
Q
two processes that are joined together and thus
seem as one process only
are always sensory neurons !!
A
Unipolar-psedopolar
19
Q
are dendrites of unipolar
(Sensory) neurons
A
Sensory receptors
20
Q
transport sensory information from skin, muscles,
joints, sense organs & viscera to CNS
A
Sensory (afferent) neurons
21
Q
send motor nerve impulses to muscles & glands
A
Motor (efferent) neurons
22
Q
connect sensory to motor neurons
90% of neurons in the body
A
Interneurons (association) neurons
- purkinje cell-bipolar-cerebellum
- Pyramidal cell-multipolar cell in the cortex of the brain
23
Q
Non-conducting cells that
assist and support neurons / nervous tissue in different
ways:
A
Glial Cells-nursery cell protect your neurons
24
Q
5 ways different ways(glial cells)
A
1.Biochemical (speed up impulses)oligodendrodyte
2. Structural (physical support) astrocyte
3. Nutritive (growth and maintenance)
4. Immune (scavenge toxins, debris)microgial
5. CSF production-epedenymal spinal cord and brain-cushoning your brain acceleration and deceleration
it kills them neurons -oxygen
25
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Flat cells surrounding
neuronal cell bodies in
peripheral ganglia
• Support neurons in
the PNS ganglia
```
Satellite Cells- exclusively pns and ganglia
26
are comprised of thousands / millions
| of nerve fibers (axon / dendrite)
Peripheral nerves-more myelinated
| Peripheral Nerve bundle of axon surrounded myelin sheath/connective tissue
27
covered by a layer of phospholipid
| substance (myelin) that electrically insulates the nerve fiber
Myelinated
28
Myelinated sheath produced by
Schwann cells myelinate 1 time (in PNS) and oligodendrocytes (in CNS) over 50 times
-Both myelinated and non-myelinated supported by schwann cell-(never naked fiber)
.
29
sheath that enhances the velocity of nerve
| impulses
nodes of Ranvier
30
almost naked nerve fibers without
| myelin sheath but still supported by Schwann cells.
Non-myelinated
31
compression, intact nerve sheaths, no
| degeneration, good prognosis.
Neuropraxia-intact
32
epineurium disrupted, degeneration,
| recovery in weeks / months.
Axonotmesis-disrupted
33
complete disruption of all covering sheaths
| and nerve, poor prognosis.
Neurotmesis-complete disruption
34
damage to axon which occur in the cell body of the affected cell; this causes swelling of the cell body and peaks
between 10 and 20 days after injury
Chromatolysis
35
By the third to fifth day, degeneration of the distal portion of
the neuronal process and myelin sheath
occurs; afterward, macrophages phagocytize the remains
Wallerian degeneration
36
the proximal portion of the fiber
| extends only for a short distance( repair in pns)
Retrograde degeneration
• Regeneration follows chromatolysis; synthesis of RNA and protein accelerates, favoring rebuilding of the axon (1.5 mm per day) and often taking several months.
nissl body-nissl body integrinate(dark stain nerve cell which is healthy( if its damage it will be pale
-distal part of the cut nerve fiber will be fragmented and those small problems making the area clean-dead myelinated/axon/ they wont remove shwann cell
- shwann cell- formed hollowed tunnel guide growing axon -it doesn't get lost- produce sprouts-20x sprouts(injured axon)- find the tunnel it keeps growing to the tunnels
- what happens go to wrong sprouts gets into tunnel- macrophage it will destroy.sensory or memory tunnels- they stay there and keep swimming few months only
- if they stay it will be hyper(neuroma)- to form neuroma super sensitive to touch- (amputation)
1. paralyzed or atropy
-first schwann tunnel will be open 90 days-3 months- nerve injury- repair the nerve
second-growth rate- 1 1/2 milimeter per day-
-200 days will recover
age,health,gap of the nerves-factors for nerve repair- knowns as walerian degeneration (repair)
-if the gap less tham 1mm- surgeons will have artificial tunnel in the lab culturing fibroblast in the lab they push fibroblast- cylinder
conduit and stitches- over 1cm(little)
37
3 steps of regeneration( Pns) and often taking several months
1.follows chromatolysis
2.synthesis of RNA
3 protein accelerates, favoring rebuilding of the axon (1.5 mm per day
38
Autoimmune disorder causing destruction of myelin sheaths in CNS
– Myelin sheaths turn into scars or plaques of fibrous tissue
– 1/2 million people in the United States
– appears between ages 20 and 40
– females twice as often as males
```
Multiple Sclerosis (MS)
1. muscular weakness
2.abnormal
sensations (such as double vision)
What happen if Remissions & relapses of ms?result in progressive, cumulative loss of function
```
39
Factors that affect speed of propagation
1. Amount of myelination
2. Axon diameter
3. Temperature
40
The propagation speed of a nerve impulse is not related to stimulus strength. (T/F)
True
41
(how)Speed of impulse propagation
– larger, myelinated fibers conduct impulses faster due to size & saltatory conduction
42
A fibers largest (5-20 microns & 130 m/sec)
myelinated somatic sensory & motor to skeletal muscle
43
B fibers medium (2-3 microns & 15 m/sec)
myelinated visceral sensory & autonomic preganglionic
44
C fibers smallest (.5-1.5 microns & 2 m/sec)
unmyelinated sensory & autonomic motor
45
* ionic current spreads to next cell through gap junctions
| * faster, two-way transmission & capable of synchronizing groups of neurons
electrical synapses
46
one-way information transfer from a presynaptic neuron to a postsynaptic neuron by neurotransmiters
chemical synapses
47
chemical synapses from axon to dendrite
axodendritic
48
chemical synapses from axon to cell body
axosomatic
49
chemical synapses from axon to axon
axoaxonic
50
3 steps how to chemical synapses
calcium- release the cell axon neurotransmitter of the receptors
sodium- rushes the target cells electrical impulse to the target cells
1.Action potential reaches end bulb and voltage-gated Ca++ channels open
2.Ca++ flows inward triggering release of neurotransmiLer
3.NeurotransmiLer crosses synaptic cleft and binds to ligand-gated receptors
• Synaptic delay is 0.5 msec
• One-way information transfer
51
released by many PNS neurons & some CNS
– excitatory on NMJ but inhibitory at others
– inactivated by acetylcholinesterase
Acetylcholine (ACh)
52
glutamate released by nearly all excitatory neurons in the
| brain ---- inactivated by glutamate specific transporters
Amino Acids
53
is inhibitory neurotransmiLer for 1/3 of all brain synapses
GABA
| example valiium-gaba agonist
54
Removal of Neurotransmitter
```
1) Diffusion
– move down concentration
gradient
2) Enzymatic degradation
– Acetylcholinesterase-removal of sypnaptic cleft
3) Uptake by neurons or glia
cells
– neurotransmiLer transporters
```
55
serotonin uptake
| inhibitor
-hippocapus-uptake inhibitorProzac
56
Neuronal Circuits single cell stimulates many others (retina)
Diverging
57
Neuronal Circuits one cell stimulated by many others (dreams)
Converging
58
Neuronal Circuits impulses from later cells repeatedly stimulate early cells in the circuit (memory)
Reverberating
59
Neuronal Circuits single cell stimulates a group of cells
| that all stimulate a common postsynaptic cell (math problems)
Parallel-after-discharge
60
brain, and
| spinal cord.
cns
61
Pns
1. spinal,
2. cranial,
3. autonomic nerves
4. ganglia,
5. enteric plexus
6. sensory receptors
62
that consciously receives sensory
information from external environment (through skin) and initiates voluntary motor activity.
- a single neuron connects the CNS with the target organ.
-Somatic component-consciously-external-voluntary
63
that unconsciously receives
sensory information from internal environment (through receptors embedded within the viscerae and initiates
involuntary motor activity.
- two neurons between CNS and the target organ.
Visceral (autonomic) component-uncosciously-internal-involuntary
64
* helps to keep controlled conditions within limits that maintain health
* helps to maintain Homeostasis
•The Nervous system (along with the Endocrine system)
Nervous system
-faster,short time affect
-specifically,nerve conduction impulses 2 meters per second.(specifically)
flexion-prime mover brachialis into elbow joint
Endocrine system-hormones which are proteins to affect the target.
-most of them blood system first,it takes a while.
Cortisol-goes to your muscle tissue to your muscle
1 second to reach on your brain-
nerve fibers-impulses 120-140 per second
65
90 percent of neurons are processing the information.
assosciate/interneuron-
66
to collect sensory/motor sensing changes and reacting to those changes done by efferrent neurons
PNS-
67
-not on cns that other remove waste csf
Lymphatic drainage
68
carrier of blood vessels and adding physical strength
1. endomysium-inside connective tissue
2. perimysium-middle connective tissue
3. epinemysium-outside connective tissue
Connective tissue-
69
- A typical peripheral nerve different shape and nerve fibers
Cross section
- common idea peripheral surface closer to the surface carries sensory fibers
- nerve is pinches-sensory- Pain- under pressure
70
numbness/weakness/parialisis- too much pressure treatment-gradually pinch nerve- motor nerve
hernia
