Axons

Card Set Information

Author:
pretty4Jesus
ID:
76573
Filename:
Axons
Updated:
2011-04-01 02:36:18
Tags:
Neuroscience Block
Folders:

Description:
axons
Show Answers:

Home > Flashcards > Print Preview

The flashcards below were created by user pretty4Jesus on FreezingBlue Flashcards. What would you like to do?


  1. Axon Facts
    • Points along axon don't have same meb pot (unlike soma- which does)
    • suprathresh- losslessness :)
    • Larger diam= lower R-> subthresh V goes further and can conduct AP at higher velocity
  2. Myelination
    • Inc R at myelin-> depol forward rather than leak out
    • R at nodes is low, g is high= LOTS of Na channels at nodes
    • **Dec Capacitance= less charge needed to get Ap; faster change in memb potential
  3. Recruitment
    Normally: smallest-> largest axonsArtif stim: largest-> smallest (largest axons have lower thresh); "inverse rank"; a challenge to prosthetics
  4. SNAP- Sensory nerve AP
    • over tendons
    • conduction study:
    • latency (conduction velocity), duration, amplitude
  5. CMAP- Compound m AP
    • over m... synch stim swamps out sens n
    • motor conduction study also: latency, duration, amplitude
    • Sensory- IA fibers, large n, low thresh-> H first
    • Inc intensity- M- othodromic
    • motor goes both way- cancels H
    • F- antidrom richasaying
  6. Peripheral Neuropathy
    • caused by demyelination or axonal defect
    • demyelination- conduction study of SNAP/CMAP-> slowed latency (conduction velocity), temperal dispersion (inc duration and dec ampl)
    • axonal- dec ampl, w/o prolonged latency
  7. Peripheral Neuropathy
    • caused by demyelination or axonal defect
    • demyelination- conduction study of SNAP/CMAP-> slowed latency (conduction velocity), temperal dispersion (inc duration and dec ampl), conduction block
    • axonal- dec ampl, w/o prolonged latency
  8. Peripheral nerve damage
    • Mild- neuropraxis
    • Crush- axonotmesis- axon damaged but basal lamina fine; Wallerian degeneration; regrowth 1mm/day helped with neurotrphins to maintain connections
    • Cut- neurotmesis- all damaged; regeneration poor
  9. CNS damage
    little regeneration because of glial scar and inhibitory factor

What would you like to do?

Home > Flashcards > Print Preview