Neuro VHA Flashcards
How do myelinated axons stain?
myelin does not stain well so they look white with large nucleus in middle
can look wavy
What surrounds a bundle of axons?
perineurium
What is structure of fibers in dorsal root ganglia?
pseudounipolar
What is contained in the dorsal root ganglia?
sensory nerves
PNS nerves
Connective tissue near axon bundle
perineurium
What is the only location where psuedounipolar cells are found?
dorsal root ganglion
What is an autonomic ganglion composed of?
cell bodies of motor neurons
Are there neuronal cell bodies in the PNS? If yes, where?
not typically in periphery
can see neuronal cell bodies in the periphery if in a ganglion
What does Nissl stain?
the RER
What can you use to stain myelin?
Luxol fast blue
Where do sensory signals pass through before reaching the spinal cord?
pass through dorsal root ganglion first
Where are bipolar neurons found?
special senses, like smell
What type of neurons are in CNS and autonomic ganglia?
multipolar
afferent fibers
sensory
deliver information from PNS to CNS
efferent fibers
motor
can cause voluntary (somatic) or involuntary (autonomic) muscle movements
where is a 2 neuron pathway found?
autonomic efferent fibers
Which cells myelinate and where?
COPS
CNS = oligodendrites
PNS = Schwann
What does gray matter contain?
glial cells and neuronal cell bodies
What does white matter contain?
glial cells and myelinated axons
How can you detect MS by staining?
when you add Luxol blue stain to find myelin there are areas of no myelination
these are plaques and representative of MS
How can you detect MS on MRI?
optic nerve is present, indicates optic neuritis
fingerlike plaques in the brain scan
What are fingerlike plaques called on MS MRI?
Dawson finger
When looking at a bundle of axons in the periphery, what are you actually seeing on stain?
actually seeing nuclei of surrounding glial cells
axon itself does not stain and neuronal cell bodies are not located in the periphery
What are the general steps of peripheral reflexes?
- relay signal to cell body in DRG
- DRG synapes with interneuron in gray matter of spinal cord
- interneuron synapes with cell body of motor neuron in gray matter
- motor neuron sends message to pull hand away
5 places where MRI is good to use
1) neuropsychiatric
2) musculoskeletal
3) cardiac
4) abdominopelvic
5) breast
T1 / T2 in MRI
T1 is bright/white for fat
T2 is bright/white for fat and water
Difference in CSF on T1/T2 images
Since T2 is bright for water, CSF will be bright on T2 scan
On T1 scan, CSF will be dark since not fat
Why is bone always black on both T1 / T2?
contains no free protons so stays black
TR in MRI
repetion time
amount of time between successive pulse sequences applied to the same slice
TE in MRI
time to echo
time between the delivery of the RF pulse and the receipt of the echo signal
diffusion
how far water molecules go through body
can use for stroke
when cells die, H2O rushes in (can see cells affected by stroke)
FLAIR in MRI
Fluid attenuated inversion recovery
special type of inversion that can remove CSF
When is FLAIR useful?
remove CSF in MS brain scans
allows us to see the Dawson finger’s better
What is fat suppression useful?
can see organs better
ex: might suppress fat in eyes to potentially see optic nerve better
gadolinium
main type of contrast used in MRI
works by changing the relaxitivity of nearby water molecules
shows blood flow and damage to blood barriers
Cancerous tissue and gadolinium
normally appears brighter when gadolinium is used since cancer is vascular and has high uptake
can be used to find hidden tumors in T1 scans!
