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167 Cards in this Set

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FIRST, WE TALK ABOUT MYELINATING GLIAL CELLS.
WOOT!
How many nerves do oligodendrocytes vs schwann cells myelinate?
oligodendrocyte- up to 50
schwann cell- only one
Hopw can you deduce this function using the cell names?
oligodendrocyte- multiple dendrites reaching out and supplying myeline
schwann cell- named after discover
Do both axons in the CNS and PNS have nodes of ranvier?
yes
What is concentrated at the membrane of nodes of ranvier?
sodium channels
NOW WE TALK ABOUT MS!
YAY!
BASIC DYSFUNCTION: What happens to myelin to damage it in the CNS?
It undergoes an inflammatory reaction if it is made by oligodendrocytes
BASIC DYSFUNCTION: What happens to nerve trasmission when myelin is inflamed?
It is impaired or blocked
BASIC DYSFUNCTION: What do we call areas that are demyelinated? Are the borders sharp or blurry?
plaques, which are sharply demarcated.
BASIC DYSFUNCTION: Where do plaques tend to show up?
in axons that run close to the the pia mater surfaces in the brain and brain stem. PERIVENTRICULAR
BASIC DYSFUNCTION: What happens to the oligodendrocytes in MS?
they scar over (called gliosis)
SYMPTOMS OF MS: What is the basic tenet about the symptoms of MS as far as when/where they show up?
The symptoms of MS are lost in time and space.
SYMPTOMS OF MS: Why are they lost in space?
they have no symmetry and can be sensory and motor
SYMPTOMS OF MS: Why are they lost in time?
the signs and sx may come and go.
DIAGNOSIS OF MS: What would a doctor look for as a time and space sign?
If 2 or more sensory or motor systems are affected in separate attacks.
BASIC DYSFUNCTION: Are any cranial nerves affected by MS?
Only CN I, the optic nerve because it is actually a tract.
MICROBIOLOGY OF MS: What would you expect to find in the CSF in MS?
elevated IgG, T-lymphocytes, and normal glucose
MICROBIOLOGY OF MS: wHY WOULD YOU FIND ELEVATED IGg AND LYMPHOCYTES IN THE csf?
Because this is a chronic attack that the immune system has seen before.
MICROBIOLOGY OF MS: What is the antigen being targeted in MS?
myelin so the antibody is anti-myelin
MICROBIOLOGY OF MS: What gene is associated with MS? (Mnemonic)
HLA-DR2 (Dr. needs to look for 2 or more systems affected)
PATHOLOGY OF MS: What is the triad of MS? (mnemonic)
Triad of MS is a SI(I)N
Scanning speech
Intention tremor
Internuclear opthalmoplegia/ Nystagmus
PATHOLOGY OF MS: What structure is affected in Internuclear opthalmoplegia/ Nystagmus?
the MLF
EPIDEMIOLOGY OF MS: What demographic is most likely to get MS?
Caucasion women 20-40 living far from the equator
TREATMENT OF MS: What is it?
immunosuppressive therapy and IFN-b aimed at reducing severity and relapse
NOW WE TALK ABOUT GUILLAIN-BARRE SYNDROME
GI-AN BARAY!
PATHOLOGY OF GBS: What is attacked in GBS and by what?
myeline made from schwann cells by our own immune cells.
PATHOLOGY OF GBS: What event is GBS usually preceded by?
respiratory or gastrointestinal illness
PATHOLOGY OF GBS: Why does the immune system attack scwann cells in this case?
We don't fully know why, but it has to do with it being very amped up.
SYMPTOMS OF GBS: What is the main symptom produced by GBS?
motor weakness with deep, aching pain
SYMPTOMS OF GBS: What is the distribution and progression?
bilateral symmetric ascending muscle weakness
PATHOLOGY OF GBS: Which cranial nerves are affected in GBS? Why?
CN 5 and 7 because they control a lot of major muscles in the head. (5-chewing 7-smiling)
PATHOLOGY OF GBS: What percentage of people will get facial paralysis?
50%
PATHOLOGY OF GBS: What is the major risk of GBS? How many people die of this?
demyelination of the phrenic nerve and loss of breathing. Less than 5% of people.
PATHOLOGY OF GBS: Is there a cure?
yes, it will go away with time and the immune attack subsiding.
PATHOLOGY OF GBS: What regular recommended doctor thing can cause GBS (think Dhruv)?
vaccinations
PATHOLOGY OF GBS: What exact part of the PNS is affected? Why is it only motor?
The VENTRAL ROOTS!
PATHOLOGY OF GBS: Can this affect autonomic nerves?
Yes, this can cause cardiac dysfunction and decreased regulation of blood pressure
PATHOLOGY OF GBS: Does it present with fever?
No
EPIDEMIOLOGY OF GBS: Are males or females more likely to get GBS?
they are equally likely
NOW WE TALK ABOUT NERVE DEGNERATION
YEAAAH!
What happens to the distal neuron if you sever the axon?
it undergoes anterograde degeneration (wallerian degeneration)
What does anterograde mean again?
anything moving away from the cell body
What kinds of axons have the capacity to regenerate? (mnemonic with polio)
only nerves with scwann cell (why you can partially recover from polio)
How do scwann cells help regenerate?
They will grow out a sheath in which the axon can grow into
Can axons in the CNS regenerate?
NOOOO! you can get a nobel prize if you discover how.
Peyton manning underwent peripheral nerve degeneration from a herniated disc. Why did it take him out for a whole year?
peripheral nerve axons can only regenerate at the rate of 1-3mm/day
Contrast this with how fast can axons transport things in anterograde and retrograde direction?
anterograde- 400 mm/day
retrograde- 200 mm/day
BACK TO THE BASICS OF THE SPINE and SPINAL CORD!
YESHHH!
How many pairs of cranial vs spinal nerves do we have?
12 pairs of CN's
31 pairs of spinal nerves
What are the two types of GANGLIA we have?
sensory and autonomic
Embryologically, why are the sensory cell bodies outside of the CNS? What kind of neurons are these?
they are derived from the neural crest cells and are pseudounipolar neurons
Why don't we have somatic motor ganglia? Where are those cell bodies?
because those cell bodies are contained in the anterior horn and derived from neural tube cells
Are there cell bodies in the dorsal horn? What kind?
Yes, but not of the PNS sensory neurons because they have dorsal root ganglia. (the cell bodies in the dorsal horn are like clarke's nucleus and substantia gelatinosa)
Where does the tapered end of the spinal cord end?
L2
What generalization can you make about branches of spinal nerves when you see them in dissection?
they are all mixed (sensory AND motor)
SPINAL CORD: What divides the anterior and lateral columns?
the lower motor neurons exiting out the anterior horn.
What is the intermediate zone of the spinal cord?
The zone in the grey matter between the dorsal and ventral horns.
What is contained in the intermediate zone?
mixed sensory and motor cell bodies
What two structures form a spinal nerve?
When the dorsal roots join with the ventral roots
Is it easy to see a spinal nerve? Why?
No, they are incredibly short because they branch into the 2 rami ver soon afterwards.
What kinds of structures do the dorsal rami innervate?
skin of the back, erector spinae muscles, and vertebral joints.
Do either of the rami innervate any viscera? Why?
No because those are innervated by the autonomic nerves which are their own crazy thing.
Do the dorsal rami have names?
No, none of them have any names.
What structures do the ventral rami innervate? Why?
skin and muscles of the trunk and all the limbs because these are anterior to the spinal nerves
Do the ventral rami have names? How many?
Yes, each and every one has a name.
What is the brachial plexus composed of?
a merging of ventral rami
What is the sciatic/ulnar/radial nerve composed of?
composites of different VENTRAL rami.
How would you categorize the ANS? motor/sensory, CNS/PNS
motor subset that can be CNS or PNS
What are the 3 main roles of the autonomic NS?
To control:
1. Glands
2. The heart (nodes and myocytes)
3. ALL Smooth muscle
Are there sensory fibers that take the same course as the autonomic fibers?
Yes, but they are not autonomic because they are sensory
What can you generally say about where the pre and post ganglionic autonomic neurons originate?
pre ganglionic- SOMEWHERE in the CNS
post ganglionic- SOMEWHERE in the PNS
What do the rami split into fairly quickly? (show pic)
cutaneous and muscular nerves
cutaneous and muscular nerves
What kinds of fibers will be found in a cutaneous nerve?
all types (sensory, and autonomic motor)
What kinds of fibers will be found in a muscular nerve?
Both. (motor for muscle and sensory for proprioception)
NOW WE TALK ABOUT DERMATONES!
DERMATASTIC!
breakdown the word dermatome
derma- skin
tome- to slice
"a slice of skin"
what is a dermatome?
It is the skin supplied by all the cutaneous branches of a pair of spinal nerves.
How many dermatomes are there? Why?
30 or 29. There is no C1 dermatome and you can argue there is no coccygeal dermatome either.
What dermatomes are on the face?
the 3 different branches of CN 5
Are the boundaries of dermatomes rigid?
No, they generally overlap
How much do they overlap?
They go into the adjacent (one over) dermatomes.
Would you be completely numb in one dermatome if you had a lesion there?
No because of the overlapping dermaterritories
NOW WE TALK ABOUT HISTOLOGY OF THE SPINAL CORD!
THIS IS SPASTIC!
What kind of stain is this? What are you trying to see?
What kind of stain is this? What are you trying to see?
A nissl stain to see neuronal rER
Why can you only see dots in the anterior horn cells of the last slide?
Because they are cell bodies large enough to be seen in a low mag stain.
What are those cell bodies a part of?
They are part of large lower motor neurons
What are the big vs small spots here? WHat are the big ones shaped like and why?
What are the big vs small spots here? WHat are the big ones shaped like and why?
Big- LMN cell bodies in a dendritic shape
Small- nissl substance of glial cells
What kind of stain is this and what is it used for?
What kind of stain is this and what is it used for?
A myelin stain used to achieve contrast
Name what each letter is
Name what each letter is
A- dorsal root
B- ventral root
C- grey matter
D- white matter
Would you see mixing of grey and white matter in a myelin stain? WHy?
Yes because axons have to come out of the grey matter and cell bodies may come out of the white matter.
NOW WE DO A SPINAL CORD REVIEW!!
YAY
How many spinal cord segments are there?
31
Show the cervical and lumbar enlargements
Why are there cervical and lumbar enlargements?
because you need extra large roots to innervate the limbs at these areas
Which segments have the cervical enlargement in them?
C5-T1 (brachial plexus)
Which segments have the lumbosacral enlargement in them?
L2-S3 (rami for the lower limbs)
Which spinal cord segmentscontain preganglionic sympathetic neurons?
T1-L2
Which spinal cord segmentscontain preganglionic parasympathetic neurons?
S2-S4
Where do the spinal cord vs the meninges end?
L2 vs S2
Which spinal cord segments are in the conus medullaris?
All the sacral segments.
What are the cauda equina structurally?
all spinal roots below L2
NOW WE TALK ABOUT THE ORGANIZATION OF GREY MATTER IN THE SPINAL CORD!
YAY THANKS
Who organized the grey matter of the spinal cord and how?
A scientist named Rexed did it and grouped similar types of neurons found there as laminae.
Show the spinal cord segment and divide it into the dorsal, intermediate, and anterior horns.
Which Rexed laminae are in the dorsal horn?
1-6
Which Rexed laminae are in the intermediate zone?
7
Which Rexed laminae are in the anterior horn?
8 and 9
Where are most of the cell bodies of the motor neurons going out to the ventral root going to be?
in the more lateral laminae 9
What does Rexed laminae 10 do?
No one knows, it just makes up the mysterior middle part
So what is found in Rexed 8 in the anterior horn?
the commissural nuclei
What types of nuclei are found in the intermediate zone?
the interomedial nuclei (for autonomic neurons)
Clarke's nucleus
Will all segments have interomedial nuclei? Which ones?
No, only the ones with autonomic output. T1-L2, S2-S4.
What kind of info is carried in Clarke's nucleus and from which parts of the body?
proprioception from the lower limbs
What spinal segments have Clarke's nuclei? How do you remember this?

Mnemonic for Clarke's nucleus?
T1-L2
same as sympathetic levels except they have nothing in common

Lewis and Clarke were travelers by LEGS who liked to take the more SYMPATHETIC routes STRAIGHT ACROSS to travel America.
NOW WE TALK ABOUT THE CLASSIFICATION OF MUSCULAR AND CUTANEOUS NERVES
YAY!
What criteria is used to rank the different types of muscular and cutaneous sensory nerves?
conduction velocity/fiber diameter
How do we name muscular nerves? Which has largest fiber diameter?
roman numerals I-!V
I is the fastest
How do we name cutaneous nerves? Which has the fastest conduction velocity?
A-alpha, A-beta, A-delta, and C
A-alpha is the fastest
so basically which ones are the fastest?
The ones earlier in line (I and A-alpha)
What are the thickest types of fibers going into the dorsal horn?
The ones coming from the muscles for proprioception
What are they called? Give them with their classifocations.
muscle spindle- Ia
golgi tendon organ- Ib
How do you remember that muscle spindles are Ia?
They were taught first in the Najeeb lecture and they are the most famous proprioceptors
What force do the muscle spindles vs golgi tendons measure in the muscle? (what makes them fire more?)
muscle spindle- muscle stretch
GTO- muscle force
What are the second thickest sensory fibers we have? (classification and modality)
A beta fibers (cutaneous)
For the touch modalities (touch, vibration, and pressure)
What are the thinnest sensory fibers (think about what is slowest to reach us)?
(classification and modality)
A-delta and C fibers for cutaneous (mostly) pain and temperature
Which fibers are responsible for fine touch?
A-beta (cutaneous) fibers
Which sensory fibers give collaterals to the dorsal column?
Ia, Ib (proprioception)
A-beta (fine touch)
Show which types of fibers are "very interested" in synapsing in the dorsal horn and which aren't.
the pain and temperature fibers
the pain and temperature fibers
What does this mean for our ability to locate where those sensations are coming from?
It is diminished (many entrances to one destination or vice versa)
Between A delta and C fibers, which one will have more synapses? Why?
C fibers because they are slower and more primitive and also cater to the viscera, creating dull, diffuse pain.
What are the two different type of efferent fibers coming out of the anterior horn?
alpha and gamma motor neurons
What will increasing gamma motor neuron firing do?
Increase muscle spindle contraction, making them MORE SENSITIVE TO STRETCH
What is added and where to the anterior horn in the spinal enlargements?
There will be more grey matter in the lateral aspect of the ventral horn.
Show where the flexors vs extensor alpha motor neurons originate in the anterior horn.
Show a picture of an arm superimposed to the ventral horn to remember proximal/distal and flexor/extensor.
Do the dorsal horns expand in the spinal enlargements? How much?
Yes because they have more sensory info to take in, but not as much as the ventral horns.
NOW WE TALK ABOUT THE AUTONOMIC NERVOUS SYSTEM!! STARTING WITH THE SYMPATHETIC SYSTEM!
yay!
How can you tell if a neuron originated from neural tube or neural crest cells? (1 determinant)
whether or not their cell body is within the CNS.
What rexed laminae/zone will a preganglionic sympathetic neuron cell body come out of?
rexed laminae 7 or the intermediate zone
How do I use the cadaver to remember that preganglionic sympathetic neurons are short?
Remember the sympathetic chain that I saw?
What is the one sympathetic exception?
The adrenal medulla.
Where do sympathetic neurons go?
EVERYWHERE!
What effect does sympathetic stimulation have on our viscera?
1. inhibition digestion
2. cardiac stimulation
3. bronchodilation
4. release of glucose
What effect does sympathetic stimulation have on our body wall?
1. constriction of blood vessel smooth muscle
2. increases sweat gland function
What are the three types of sympathetic ganglia?
1. Prevertebral
2. Paravertebral
3. Adrenal
Where can you find the prevertebral ganglia chain? What are they named for?
In front (PRE) of the spinal column inferior to the diaphragm and they are named for the blood vessel they run along.
Where can you find the paravertebral ganglia chain?
On either side of the spinal column
What structures does the prevertebral ganglia supply? How did you deduce this?
the viscera (you know this because they are below the diaphragm with the viscera)
What structures does the paravertebral ganglia supply? How did you deduce this?
The body wall (they are so nice and organized on the cadaver that it couldn't possibly be the viscera)
What is another name for the adrenal ganglia?
The cromaffin cells because they release catecholamines in response to sympathetic pregaglionic stimulation
What sympathetically controlled structures does the face have in common with the rest of the body walls?
vascular SM and sweat glands
What additional sympathetic structures does the face have? (think Horner's) (2)
2 smooth muscles of the orbit
superior tarsal muscle to raise the eyelids
pupillary dilator muscle
What spinal level gives sympathetic control to the face?
T1
What ganglion supplies sympathetic control to the whole face?
The superior cervical ganglion
Which chain of ganglia does the face sympathetic fibers travel up? How do you know this? (para/pre)
The prevertebral because this chain supplies body walls
Can you show where this ganglion is?
What kind of tumor could compress the superior cervical ganglion? What disorder would this cause?
a neck tumor. This would cause ipsilateral horner's syndrome
Is the autonomic chain a 2 neuron pathway? How many are there?
NO! We haven't been told the whole truth. There are 3!
Where is the 3rd one from and where does it connect? What is it called?
Descending HYPOTHALAMIC tracts ending on preganglionic fibers.
Explain all the symptoms of horner's synrome and give it's sidedness.
ipsilateral:
Ptosis- droopy eyelid
Anhydrosis- loss of sweating
Miosis- constricted pupil
What is so clinically significant about horner's syndrome?
It indicates a lesion anywhere from the sympathetics of the hypothalamus to the superior cervical ganglion.
(including the descending hypothalamic fibers, making it like a babinski's sign)
NOW WE TALK ABOUT THE PARASYMPATHETIC SYSTEM!
LAST ONE OF THIS LECTURE!
If the sympathetics are thoracolumbar, what are the parasympathetics?
craniosacral
Which cranial and which sacral levels?
cranial- CN 3,7, 9, 10
sacral- S2-4
What parasympathetic function does each cranial nerve do?
CN 3- edinger westphal- constrict pupils to light on both sides
CN 7- salivation
CN 9- same as 10
CN 10- visceral functions
What parasympathetic function does the sacral nerves have?
bladder and bowel (hindgut) emptying
ANATOMY: Do the PS and S controlling neurons in the CNS run in a predictable bundle/tract?
sympathetics do, but we don't know about the PS's yet