Neuron+Questions+SLS

October 13, 2008 Human Bio-1**
 * Shelby Smith


 * Neurons**


 * Neurons**


 * Neuron Structure**
 * 1. Insert an image of the basic neuron structure that includes cell body, dendrites, and axon. p. 249**

This is caused by the loss of myelin from the axons. MS is believed to be caused by an attack on the myelin by the body’s immune system.
 * Myelin Sheath**
 * 2. Insert an image of a neuron with a myelin sheath**.
 * 3. What is the myelin sheath made of? Where is it located? What is its function? p. 249** The myelin sheath is made of neurolgia called Schwann cells, which contain myelin (a lipid substance) in their plasmas.
 * 4. What is the difference between the "gray matter" and "white matter" in the brain? p.249** Gray matter is gray because it contains no myelinated axons, and the white matter is white because it does have the myelinated axons.
 * 5. What causes multiple sclerosis? P.249**

The sodium ions are outside of the axon and the potassium ions are found inside the axon. The charge inside the axon negative. Potassium can permeate the membrane. The sodium goes into the axon and the charge changes from negative to positive. Potassium flows to the outside of the axon and the charge of the axon resumes negative. Depolarization is when the charge changes from negative to positive and repolarization is when the charge resumes negative. The opening of the Sodium Gate. The opening of the Potassium Gate. Action potential is the rapid change in polarity across an axonal membrane as the nerve impulse occurs. The work of the pump maintains unequal distribution. Neurotransmitters from one neuron to the next via electrical charge. The synaptic cleft is a small gap that separates the receiving neron to the transmitting neuron. Starts the synapse process. Electrical charge.
 * Nerve Impulse p.250-252**
 * 5. Where are the sodium and potassium ions when the axon is at rest? What is the charge inside the axon?**
 * 6. Which ions can cross the membrane and enter the axon? potassium or sodium?**
 * 7. What happens to the charge inside the axon when sodium gates open? Where does sodium go?**
 * 8. What happens to the charge inside the axon when the potassium gates open? Where does potassium go?**
 * 9. Look at the graph on page 251. What do you think depolarization means? What do you think repolarization means?**
 * 10. What causes depolarization of the axon?**
 * 11. What causes repolarization of the axon?**
 * 12. What is an action potential?**
 * 13. How does the sodium potassium pump reestablish the resting potential during the refractory period?**
 * 14. What is a synapse?**
 * 15. What is a synaptic cleft?**
 * 16. What is a neurotransmitter?**
 * 17. Since neuron's don't touch, how is the signal from one neuron transmitted to another neuron?**
 * 18. Insert an image showing an action potential.**
 * 19. Insert an image showing a synapse. **