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167 Cards in this Set
- Front
- Back
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FIRST, WE TALK ABOUT MYELINATING GLIAL CELLS.
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WOOT!
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How many nerves do oligodendrocytes vs schwann cells myelinate?
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oligodendrocyte- up to 50
schwann cell- only one |
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Hopw can you deduce this function using the cell names?
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oligodendrocyte- multiple dendrites reaching out and supplying myeline
schwann cell- named after discover |
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Do both axons in the CNS and PNS have nodes of ranvier?
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yes
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What is concentrated at the membrane of nodes of ranvier?
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sodium channels
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NOW WE TALK ABOUT MS!
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YAY!
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BASIC DYSFUNCTION: What happens to myelin to damage it in the CNS?
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It undergoes an inflammatory reaction if it is made by oligodendrocytes
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BASIC DYSFUNCTION: What happens to nerve trasmission when myelin is inflamed?
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It is impaired or blocked
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BASIC DYSFUNCTION: What do we call areas that are demyelinated? Are the borders sharp or blurry?
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plaques, which are sharply demarcated.
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BASIC DYSFUNCTION: Where do plaques tend to show up?
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in axons that run close to the the pia mater surfaces in the brain and brain stem. PERIVENTRICULAR
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BASIC DYSFUNCTION: What happens to the oligodendrocytes in MS?
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they scar over (called gliosis)
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SYMPTOMS OF MS: What is the basic tenet about the symptoms of MS as far as when/where they show up?
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The symptoms of MS are lost in time and space.
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SYMPTOMS OF MS: Why are they lost in space?
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they have no symmetry and can be sensory and motor
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SYMPTOMS OF MS: Why are they lost in time?
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the signs and sx may come and go.
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DIAGNOSIS OF MS: What would a doctor look for as a time and space sign?
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If 2 or more sensory or motor systems are affected in separate attacks.
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BASIC DYSFUNCTION: Are any cranial nerves affected by MS?
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Only CN I, the optic nerve because it is actually a tract.
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MICROBIOLOGY OF MS: What would you expect to find in the CSF in MS?
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elevated IgG, T-lymphocytes, and normal glucose
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MICROBIOLOGY OF MS: wHY WOULD YOU FIND ELEVATED IGg AND LYMPHOCYTES IN THE csf?
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Because this is a chronic attack that the immune system has seen before.
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MICROBIOLOGY OF MS: What is the antigen being targeted in MS?
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myelin so the antibody is anti-myelin
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MICROBIOLOGY OF MS: What gene is associated with MS? (Mnemonic)
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HLA-DR2 (Dr. needs to look for 2 or more systems affected)
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PATHOLOGY OF MS: What is the triad of MS? (mnemonic)
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Triad of MS is a SI(I)N
Scanning speech Intention tremor Internuclear opthalmoplegia/ Nystagmus |
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PATHOLOGY OF MS: What structure is affected in Internuclear opthalmoplegia/ Nystagmus?
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the MLF
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EPIDEMIOLOGY OF MS: What demographic is most likely to get MS?
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Caucasion women 20-40 living far from the equator
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TREATMENT OF MS: What is it?
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immunosuppressive therapy and IFN-b aimed at reducing severity and relapse
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NOW WE TALK ABOUT GUILLAIN-BARRE SYNDROME
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GI-AN BARAY!
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PATHOLOGY OF GBS: What is attacked in GBS and by what?
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myeline made from schwann cells by our own immune cells.
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PATHOLOGY OF GBS: What event is GBS usually preceded by?
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respiratory or gastrointestinal illness
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PATHOLOGY OF GBS: Why does the immune system attack scwann cells in this case?
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We don't fully know why, but it has to do with it being very amped up.
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SYMPTOMS OF GBS: What is the main symptom produced by GBS?
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motor weakness with deep, aching pain
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SYMPTOMS OF GBS: What is the distribution and progression?
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bilateral symmetric ascending muscle weakness
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PATHOLOGY OF GBS: Which cranial nerves are affected in GBS? Why?
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CN 5 and 7 because they control a lot of major muscles in the head. (5-chewing 7-smiling)
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PATHOLOGY OF GBS: What percentage of people will get facial paralysis?
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50%
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PATHOLOGY OF GBS: What is the major risk of GBS? How many people die of this?
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demyelination of the phrenic nerve and loss of breathing. Less than 5% of people.
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PATHOLOGY OF GBS: Is there a cure?
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yes, it will go away with time and the immune attack subsiding.
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PATHOLOGY OF GBS: What regular recommended doctor thing can cause GBS (think Dhruv)?
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vaccinations
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PATHOLOGY OF GBS: What exact part of the PNS is affected? Why is it only motor?
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The VENTRAL ROOTS!
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PATHOLOGY OF GBS: Can this affect autonomic nerves?
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Yes, this can cause cardiac dysfunction and decreased regulation of blood pressure
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PATHOLOGY OF GBS: Does it present with fever?
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No
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EPIDEMIOLOGY OF GBS: Are males or females more likely to get GBS?
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they are equally likely
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NOW WE TALK ABOUT NERVE DEGNERATION
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YEAAAH!
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What happens to the distal neuron if you sever the axon?
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it undergoes anterograde degeneration (wallerian degeneration)
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What does anterograde mean again?
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anything moving away from the cell body
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What kinds of axons have the capacity to regenerate? (mnemonic with polio)
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only nerves with scwann cell (why you can partially recover from polio)
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How do scwann cells help regenerate?
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They will grow out a sheath in which the axon can grow into
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Can axons in the CNS regenerate?
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NOOOO! you can get a nobel prize if you discover how.
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Peyton manning underwent peripheral nerve degeneration from a herniated disc. Why did it take him out for a whole year?
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peripheral nerve axons can only regenerate at the rate of 1-3mm/day
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Contrast this with how fast can axons transport things in anterograde and retrograde direction?
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anterograde- 400 mm/day
retrograde- 200 mm/day |
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BACK TO THE BASICS OF THE SPINE and SPINAL CORD!
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YESHHH!
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How many pairs of cranial vs spinal nerves do we have?
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12 pairs of CN's
31 pairs of spinal nerves |
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What are the two types of GANGLIA we have?
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sensory and autonomic
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Embryologically, why are the sensory cell bodies outside of the CNS? What kind of neurons are these?
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they are derived from the neural crest cells and are pseudounipolar neurons
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Why don't we have somatic motor ganglia? Where are those cell bodies?
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because those cell bodies are contained in the anterior horn and derived from neural tube cells
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Are there cell bodies in the dorsal horn? What kind?
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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)
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Where does the tapered end of the spinal cord end?
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L2
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What generalization can you make about branches of spinal nerves when you see them in dissection?
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they are all mixed (sensory AND motor)
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SPINAL CORD: What divides the anterior and lateral columns?
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the lower motor neurons exiting out the anterior horn.
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What is the intermediate zone of the spinal cord?
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The zone in the grey matter between the dorsal and ventral horns.
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What is contained in the intermediate zone?
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mixed sensory and motor cell bodies
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What two structures form a spinal nerve?
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When the dorsal roots join with the ventral roots
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Is it easy to see a spinal nerve? Why?
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No, they are incredibly short because they branch into the 2 rami ver soon afterwards.
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What kinds of structures do the dorsal rami innervate?
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skin of the back, erector spinae muscles, and vertebral joints.
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Do either of the rami innervate any viscera? Why?
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No because those are innervated by the autonomic nerves which are their own crazy thing.
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Do the dorsal rami have names?
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No, none of them have any names.
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What structures do the ventral rami innervate? Why?
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skin and muscles of the trunk and all the limbs because these are anterior to the spinal nerves
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Do the ventral rami have names? How many?
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Yes, each and every one has a name.
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What is the brachial plexus composed of?
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a merging of ventral rami
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What is the sciatic/ulnar/radial nerve composed of?
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composites of different VENTRAL rami.
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How would you categorize the ANS? motor/sensory, CNS/PNS
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motor subset that can be CNS or PNS
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What are the 3 main roles of the autonomic NS?
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To control:
1. Glands 2. The heart (nodes and myocytes) 3. ALL Smooth muscle |
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Are there sensory fibers that take the same course as the autonomic fibers?
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Yes, but they are not autonomic because they are sensory
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What can you generally say about where the pre and post ganglionic autonomic neurons originate?
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pre ganglionic- SOMEWHERE in the CNS
post ganglionic- SOMEWHERE in the PNS |
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What do the rami split into fairly quickly? (show pic)
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cutaneous and muscular nerves
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What kinds of fibers will be found in a cutaneous nerve?
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all types (sensory, and autonomic motor)
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What kinds of fibers will be found in a muscular nerve?
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Both. (motor for muscle and sensory for proprioception)
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NOW WE TALK ABOUT DERMATONES!
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DERMATASTIC!
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breakdown the word dermatome
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derma- skin
tome- to slice "a slice of skin" |
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what is a dermatome?
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It is the skin supplied by all the cutaneous branches of a pair of spinal nerves.
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How many dermatomes are there? Why?
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30 or 29. There is no C1 dermatome and you can argue there is no coccygeal dermatome either.
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What dermatomes are on the face?
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the 3 different branches of CN 5
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Are the boundaries of dermatomes rigid?
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No, they generally overlap
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How much do they overlap?
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They go into the adjacent (one over) dermatomes.
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Would you be completely numb in one dermatome if you had a lesion there?
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No because of the overlapping dermaterritories
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NOW WE TALK ABOUT HISTOLOGY OF THE SPINAL CORD!
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THIS IS SPASTIC!
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What kind of stain is this? What are you trying to see?
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A nissl stain to see neuronal rER
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Why can you only see dots in the anterior horn cells of the last slide?
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Because they are cell bodies large enough to be seen in a low mag stain.
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What are those cell bodies a part of?
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They are part of large lower motor neurons
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What are the big vs small spots here? WHat are the big ones shaped like and why?
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Big- LMN cell bodies in a dendritic shape
Small- nissl substance of glial cells |
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What kind of stain is this and what is it used for?
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A myelin stain used to achieve contrast
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Name what each letter is
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A- dorsal root
B- ventral root C- grey matter D- white matter |
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Would you see mixing of grey and white matter in a myelin stain? WHy?
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Yes because axons have to come out of the grey matter and cell bodies may come out of the white matter.
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NOW WE DO A SPINAL CORD REVIEW!!
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YAY
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How many spinal cord segments are there?
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31
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Show the cervical and lumbar enlargements
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Why are there cervical and lumbar enlargements?
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because you need extra large roots to innervate the limbs at these areas
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Which segments have the cervical enlargement in them?
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C5-T1 (brachial plexus)
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Which segments have the lumbosacral enlargement in them?
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L2-S3 (rami for the lower limbs)
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Which spinal cord segmentscontain preganglionic sympathetic neurons?
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T1-L2
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Which spinal cord segmentscontain preganglionic parasympathetic neurons?
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S2-S4
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Where do the spinal cord vs the meninges end?
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L2 vs S2
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Which spinal cord segments are in the conus medullaris?
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All the sacral segments.
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What are the cauda equina structurally?
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all spinal roots below L2
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NOW WE TALK ABOUT THE ORGANIZATION OF GREY MATTER IN THE SPINAL CORD!
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YAY THANKS
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Who organized the grey matter of the spinal cord and how?
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A scientist named Rexed did it and grouped similar types of neurons found there as laminae.
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Show the spinal cord segment and divide it into the dorsal, intermediate, and anterior horns.
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Which Rexed laminae are in the dorsal horn?
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1-6
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Which Rexed laminae are in the intermediate zone?
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7
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Which Rexed laminae are in the anterior horn?
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8 and 9
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Where are most of the cell bodies of the motor neurons going out to the ventral root going to be?
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in the more lateral laminae 9
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What does Rexed laminae 10 do?
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No one knows, it just makes up the mysterior middle part
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So what is found in Rexed 8 in the anterior horn?
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the commissural nuclei
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What types of nuclei are found in the intermediate zone?
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the interomedial nuclei (for autonomic neurons)
Clarke's nucleus |
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Will all segments have interomedial nuclei? Which ones?
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No, only the ones with autonomic output. T1-L2, S2-S4.
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What kind of info is carried in Clarke's nucleus and from which parts of the body?
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proprioception from the lower limbs
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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. |
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NOW WE TALK ABOUT THE CLASSIFICATION OF MUSCULAR AND CUTANEOUS NERVES
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YAY!
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What criteria is used to rank the different types of muscular and cutaneous sensory nerves?
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conduction velocity/fiber diameter
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How do we name muscular nerves? Which has largest fiber diameter?
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roman numerals I-!V
I is the fastest |
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How do we name cutaneous nerves? Which has the fastest conduction velocity?
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A-alpha, A-beta, A-delta, and C
A-alpha is the fastest |
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so basically which ones are the fastest?
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The ones earlier in line (I and A-alpha)
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What are the thickest types of fibers going into the dorsal horn?
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The ones coming from the muscles for proprioception
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What are they called? Give them with their classifocations.
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muscle spindle- Ia
golgi tendon organ- Ib |
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How do you remember that muscle spindles are Ia?
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They were taught first in the Najeeb lecture and they are the most famous proprioceptors
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What force do the muscle spindles vs golgi tendons measure in the muscle? (what makes them fire more?)
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muscle spindle- muscle stretch
GTO- muscle force |
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What are the second thickest sensory fibers we have? (classification and modality)
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A beta fibers (cutaneous)
For the touch modalities (touch, vibration, and pressure) |
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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
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Which fibers are responsible for fine touch?
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A-beta (cutaneous) fibers
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Which sensory fibers give collaterals to the dorsal column?
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Ia, Ib (proprioception)
A-beta (fine touch) |
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Show which types of fibers are "very interested" in synapsing in the dorsal horn and which aren't.
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the pain and temperature fibers
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What does this mean for our ability to locate where those sensations are coming from?
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It is diminished (many entrances to one destination or vice versa)
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Between A delta and C fibers, which one will have more synapses? Why?
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C fibers because they are slower and more primitive and also cater to the viscera, creating dull, diffuse pain.
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What are the two different type of efferent fibers coming out of the anterior horn?
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alpha and gamma motor neurons
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What will increasing gamma motor neuron firing do?
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Increase muscle spindle contraction, making them MORE SENSITIVE TO STRETCH
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What is added and where to the anterior horn in the spinal enlargements?
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There will be more grey matter in the lateral aspect of the ventral horn.
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Show where the flexors vs extensor alpha motor neurons originate in the anterior horn.
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Show a picture of an arm superimposed to the ventral horn to remember proximal/distal and flexor/extensor.
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Do the dorsal horns expand in the spinal enlargements? How much?
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Yes because they have more sensory info to take in, but not as much as the ventral horns.
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NOW WE TALK ABOUT THE AUTONOMIC NERVOUS SYSTEM!! STARTING WITH THE SYMPATHETIC SYSTEM!
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yay!
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How can you tell if a neuron originated from neural tube or neural crest cells? (1 determinant)
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whether or not their cell body is within the CNS.
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What rexed laminae/zone will a preganglionic sympathetic neuron cell body come out of?
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rexed laminae 7 or the intermediate zone
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How do I use the cadaver to remember that preganglionic sympathetic neurons are short?
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Remember the sympathetic chain that I saw?
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What is the one sympathetic exception?
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The adrenal medulla.
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Where do sympathetic neurons go?
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EVERYWHERE!
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What effect does sympathetic stimulation have on our viscera?
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1. inhibition digestion
2. cardiac stimulation 3. bronchodilation 4. release of glucose |
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What effect does sympathetic stimulation have on our body wall?
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1. constriction of blood vessel smooth muscle
2. increases sweat gland function |
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What are the three types of sympathetic ganglia?
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1. Prevertebral
2. Paravertebral 3. Adrenal |
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Where can you find the prevertebral ganglia chain? What are they named for?
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In front (PRE) of the spinal column inferior to the diaphragm and they are named for the blood vessel they run along.
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Where can you find the paravertebral ganglia chain?
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On either side of the spinal column
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What structures does the prevertebral ganglia supply? How did you deduce this?
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the viscera (you know this because they are below the diaphragm with the viscera)
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What structures does the paravertebral ganglia supply? How did you deduce this?
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The body wall (they are so nice and organized on the cadaver that it couldn't possibly be the viscera)
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What is another name for the adrenal ganglia?
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The cromaffin cells because they release catecholamines in response to sympathetic pregaglionic stimulation
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What sympathetically controlled structures does the face have in common with the rest of the body walls?
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vascular SM and sweat glands
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What additional sympathetic structures does the face have? (think Horner's) (2)
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2 smooth muscles of the orbit
superior tarsal muscle to raise the eyelids pupillary dilator muscle |
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What spinal level gives sympathetic control to the face?
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T1
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What ganglion supplies sympathetic control to the whole face?
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The superior cervical ganglion
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Which chain of ganglia does the face sympathetic fibers travel up? How do you know this? (para/pre)
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The prevertebral because this chain supplies body walls
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Can you show where this ganglion is?
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What kind of tumor could compress the superior cervical ganglion? What disorder would this cause?
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a neck tumor. This would cause ipsilateral horner's syndrome
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Is the autonomic chain a 2 neuron pathway? How many are there?
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NO! We haven't been told the whole truth. There are 3!
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Where is the 3rd one from and where does it connect? What is it called?
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Descending HYPOTHALAMIC tracts ending on preganglionic fibers.
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Explain all the symptoms of horner's synrome and give it's sidedness.
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ipsilateral:
Ptosis- droopy eyelid Anhydrosis- loss of sweating Miosis- constricted pupil |
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What is so clinically significant about horner's syndrome?
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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) |
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NOW WE TALK ABOUT THE PARASYMPATHETIC SYSTEM!
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LAST ONE OF THIS LECTURE!
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If the sympathetics are thoracolumbar, what are the parasympathetics?
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craniosacral
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Which cranial and which sacral levels?
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cranial- CN 3,7, 9, 10
sacral- S2-4 |
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What parasympathetic function does each cranial nerve do?
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CN 3- edinger westphal- constrict pupils to light on both sides
CN 7- salivation CN 9- same as 10 CN 10- visceral functions |
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What parasympathetic function does the sacral nerves have?
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bladder and bowel (hindgut) emptying
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ANATOMY: Do the PS and S controlling neurons in the CNS run in a predictable bundle/tract?
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sympathetics do, but we don't know about the PS's yet
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