1. The Nervous System Jason, Luisa, Dan, and Sheila

2. The Nervous System -The nervous system is an organ system that acts as the information highway for the body and consists of many nerve cells (1). -Nervous systems are made up of two cell types: neurons, and glial cells(2). -Neurons work to monitor the conditions in and around the body(1). They give commands for responsive actions throughout the organism(1).

3. Motor Neurons A motor neuron is a type of neuron specialized to relay commands from the brain or spinal cord to muscle cells, and gland cells (1).

4. Structure of a Motor Neuron (1) - Dendrites, the " satellite dishes" They receive information - The cell body contains organelles present in animal cells. - The axon, " wiring" They send information - myelin sheath, " wire covering" made of fats for insulation

5. Ions -Major ions are K+ and Na+ (2) - These ions cross the membrane through sodium and potassium protein pumps (Na is pumped out, K is pumped in) (2) -more sodium is pumped out than potassium in (2) - Because of unequal pumping, a greater positive charge exists outside of the neuron, while the cytoplasm inside the ion is negatively charged (2)

6. Ions (cont.) -At rest, the neuron is polarized with a negative charge (2) -Active transport will cause the electronic imbalance to become larger and gated channels will open (2) -The neuron then becomes depolarized (more positive) (2) -Pumps and potassium channels (which open) rebalance polarization (2)

7. Action Potential (2) The process of depolarization and repolarization - The Threshold level

8. (6)

9. Importance of Myelin Myelin is imperative to proper function of the human body. Without this functional insulation, the axons could no longer effectively conduct signals. This would result in symptoms ranging from mild to severe. (3)

10. Myelin Disorders Demyelination: loss of myelin insulation. (3) -Multiple sclerosis, acute disseminated encephalomyelitis, and Guillain-Barré Syndrome. (4) Dysmyelination: insufficient or defective myelin.(3) - caused by genetic abnormailites - leukodystrohies, schizophrenia (3) Van Gogh was a notable schizophrenic

11. References 1. Farabee, Mike. "the nervous system". Estrella Mountain Community College. Date Written Unknown. Accessed 4 Nov. 2010. 2. Gregory, Michael. "Neurons". Clinton Community College. Date Written Unknown. Web. 4 Nov. 2010. 3. Unknown, Author. "Myelin." National MS Society. Date written unknown. Accessed 4 Nov. 2010.. 4. Unknown, Author. "Multiple Sclerosis." Internet Health Library. 5 Dec. 2006. accessed 4 Nov. 2010. 5. Starr, Cecie, and Ralph Taggart. Diversity of life: Biology: The unity and diversity of life. 7. revised ed. Belmont, Calif.: Wadsworth Publ., 1995. Print. 6. "YouTube- Action Potenital." YouTube - Broadcast Yourself.. N.p., n.d. Web. 5 Nov. 2010..