1. Nervous System Maddie Picher, Rachel Quigley, Lisa Waddell

2. Structures of a Motor Neuron dendrites (processes) [dendrite spine] o conducts impulses from other neurons down to the axon cell body (soma) o the nucleus o cell membrane o other parts of a normal cell o where protein synthesis occurs axon o myelin sheath o nodes of ranvier o where the chemical reactions occur synaptic terminal o where the neurotransmitters are released to bind with the dendrites of neighboring neuron

3. Myelin Sheath Comprised of fat Insulates the axon from electrical activity: maintains resting potential and aids action potential The nodes of ranvier between the myelin sheath on the axon cause rapid saltatory conduction of impulses across the nodes resulting in a faster transmitted impulse Demyelination (deterioration of the myelin sheath) is known to be a contributor to lack of muscle and speech control (parkinson's disease)

4. Ions in the Neuron at Rest: Electric currents disturb the trigger region, that has gated channels Protein Channels between cytoplasm (-) (NA) and interstitial fluid (+) (K) Charge difference is maintained through active transport of the Sodium-Potassium pumps (use of ATP) Sodium out, Potassium in at ratio of 3:2 Result: (+) outside (-) inside of neutron Resting Membrane Potential: difference of charges (-70mV)

5. The Nerve Impulse As a reaction to a stimulus, rapid depolarization happens, causing a change in charge causing the impulse Depolarized: inside of cell (+) and outside (-) Action Potential: Moving depolarization; one transport effects neighboring channels To bring back to resting state, active transport takes place again, balancing the cell– the inside of the plasma membrane becomes negative once again and repolarizes the membrane

6. Action Potential occurs when a portion of the membrane rapidly depolarizes then repolarizes again to the original resting state initiated by stimulus reversal in voltage difference across plasma membrane (about +30mV)

7. Animation http://highered.mcgraw- hill.com/sites/0072495855/student_view0/ chapter14/animation__the_nerve_impulse. html

8. Sources Biolog911. N.p., n.d. Web. 2 Nov. 2012. <http://biolog911.wordpress.com/2011/ 05/03/human-nervous-system/>. Medical Dictionary. N.p., n.d. Web. 2 Nov. 2012.. Human Anatomy. N.p., n.d. Web. 2 Nov. 2012. <http://highered.mcgraw-hill.com/ sites/0072495855/student_view0/chapter14/animation__the_nerve_impulse.html>. Gesine Saher, Fabian Rudolphi, Kristina Corthals, Torben Ruhwedel, Karl-Friedrich Schmidt, Siegrid Löwel, Payam Dibaj, Benoit Barrette, Wiebke Möbius & Klaus-Armin Nave, (2012). Therapy of Pelizaeus-Merzbacher disease in mice by feeding a cholesterol-enriched diet. Nature Medicine.Therapy of Pelizaeus-Merzbacher disease in mice by feeding a cholesterol-enriched diet "Structure of the Neuron - Myelin Sheath." Structure of the Neuron - Myelin Sheath. Webmaster@psych.athabascau.ca, 17 Mar. 2008. Web. 05 Nov. 2012..