neurons+in+my+brainy

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

Myelin Sheath 2. Insert an image of a neuron with a myelin sheath. ABOVE 3. What is the myelin sheath made of? Where is it located? What is its function? p. 249 A myelin sheath is made of a fatty white material located on the nerve cell. It is used as an insulator for the cell and also helps with nerve regeneration. 4. What is the difference between the "gray matter" and "white matter" in the brain? p.249 the gray matter doesnt have any myelinated axons and the white does. 5. What causes multiple sclerosis? P.249 when the body's immune system attacks the myelin

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? Sodium ions are on the outside and potassium are on the inside and the charge on the inside of the axon is negative. 6. Which ions can cross the membrane and enter the axon? potassium or sodium? sodium 7. What happens to the charge inside the axon when sodium gates open? Where does sodium go? the axon depolarizes, goes from negative to positive. 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? when the axon goes from negative to positive it is being depolorized. repolorization is when the potassium goes back out of the membrane and the axon becomes negative again. 10. What causes depolarization of the axon? when sodium enters the axon making it positively charged 11. What causes repolarization of the axon? when the potassium exits the ion making it negatively charged again. 12. What is an action potential? a quick change in the charge of the axonal membrane as the nerve impulses. 13. How does the sodium potassium pump reestablish the resting potential during the refractory period? The pump closes during the refractory period to make sure the action potential always moves down the axon.a 14. What is a synapse? a synapse is the term used to describe the terminals close proximity to a dendrite or a different neuron's cell body. 15. What is a synaptic cleft? the seperation in the sending and receiving neuron. 16. What is a neurotransmitter? a molecule that carries transmissions across the synapse. 17. Since neuron's don't touch, how is the signal from one neuron transmitted to another neuron? a neurotransmitter is released and diffuses across a synaptic cleft and binds to a receptor in the membrane of the receiving neuron. 18. Insert an image showing an action potential. 19. Insert an image showing a synapse.