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Sciatic Nerve Biology Lab Quiz - Frog Sciatic Nerve Exercises Review

This announcement provides a review of the last week's lab focusing on muscle receptor organ of crayfish. The upcoming lab quiz will be based on the crayfish demo and sciatic nerve exercises. The review includes information on the sciatic nerve of a leopard frog and its goals, such as determining threshold, measuring compound action potentials (APs), observing recruitment, calculating conduction velocity, and more. The text outlines the instrumentation and setup required for the lab, including the nerve bath chamber, electrodes, electrode placement tips, and the iWorx unit.

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Sciatic Nerve Biology Lab Quiz - Frog Sciatic Nerve Exercises Review

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  1. THE FROG SCIATIC NERVE BIOLOGY 305 LABORATORY

  2. ANNOUNCEMENTS • Lab Quiz: • Next week in lab • Based on: • Crayfish Demo • Sciatic Nerve Exercises

  3. REVIEW OF LAST WEEK: MUSCLE RECEPTOR ORGAN OF CRAYFISH Flow of Information: • MRO Nerve • Suction Electrode • Junction box (amplifier) • Audio amplifier • Iworx box • Computer (LabScribe)

  4. REVIEW OF LAST WEEK: MUSCLE RECEPTOR ORGAN OF CRAYFISH • MRO1: • MRO2s: • Sensory Adaptation:

  5. THE SCIATIC NERVE • Leopard Frog: • Sciatic Nerve: • Composed of Mixed Axons: www.zoo.utoronto.ca/natalie/ frogpage.html

  6. THE SCIATIC NERVE • Goals Include: • Determine threshold • Measure compound APs • Observe recruitment • Calculate conduction velocity • See temperature influences • Determine directionality

  7. THE SCIATIC NERVE • Each Neuron Has A Threshold: • Voltage at which a neuron is sufficiently stimulated to fire an Action Potential (AP) • Sub threshold stimulus 

  8. THE SCIATIC NERVE • Compound Action Potentials (CAP): • Summation of action potentials (APs)

  9. THE SCIATIC NERVE • Recruitment: • As you apply supra-threshold stimuli to a nerve with increasing voltage

  10. THE SCIATIC NERVE • Maximum Recruitment: • At some stimulus voltage

  11. THE SCIATIC NERVE • The Stimulus Artifact: • Deflection due to application of voltage to nerve • If stimulus exceeds 0 Volts, you should see a stimulus artifact on trace

  12. THE SCIATIC NERVE • Conduction Velocity of APs: • In a single neuron, depends on • In lab you’ll measure conduction velocity of a CAP at room temperature and under cold conditions

  13. THE SCIATIC NERVE • Directionality: • In an excised sciatic nerve, CAPs should travel

  14. THE SCIATIC NERVE The Dissection: • To minimize # of animals used, each group will share a frog with another group

  15. THE SCIATIC NERVE The Dissection: • Excision of Distal End www.engin.brown.edu/.../MuscleExp/ Dissection.htm

  16. THE SCIATIC NERVE The Dissection: • Excision of Proximal End www.engin.brown.edu/.../MuscleExp/ Dissection.htm

  17. THE SCIATIC NERVE Instrumentation & Set Up: • The Nerve Bath Chamber: www.biopac.com/newsletter/ september/frog_nerve.ht

  18. THE SCIATIC NERVE Instrumentation & Set Up: • Electrodes:

  19. Recording Electrodes Nerve Bath Chamber Stimulating Electrodes

  20. THE SCIATIC NERVE Instrumentation & Set Up: • Electrodes • Place + & – leads on opposite sides of bath • Space apart by one pin • No two electrodes should be attached to same pin!

  21. THE SCIATIC NERVE Instrumentation & Set Up • Electrode Tips: • Confirm everything is plugged in • Confirm good electrical contact • Only connect electrodes to pins in contact with nerve! • Remove excess Ringer’s from nerve & pins in bath while running experiments

  22. THE SCIATIC NERVE Instrumentation & Set Up: • iWORX Unit

  23. THE SCIATIC NERVE iWorx Stimulator Panel (OUTPUT) iWorx Recording Channels (INPUT)

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