Science Starter What are the 3 types of neurons that exist? What are the 2 types of messages a neuron can send? What is the axon responsible for? What kind of message is an action potential?

Today’s Agenda Science Starter Epilepsy Video Action Potential Models Class Discussion Exit Quiz

Do you know how it is treated? Epilepsy Video What is epilepsy? Do you know how it is treated? http://www.cbsnews.com/news/study-finds-marijuana-extract-may-help-children-with-epilepsy/

Modeling the Action Potential In groups designate the following: Materials Coordinator (2) Bean mover Data recorder/Questions Set up your model to look the like the back of the introduction picture (a) Bowls are filled (each with few vs. many ions) Cell drawn on paper Toothpicks arranged as ion channels Post-it notes with “negative” and “positive” arranged

Outside of Cell Inside of Cell Na+ (many) Na+ (few) K+ (few) K+ (many) Cl- (many) Cl- (few) Outside of Cell Gate Gate Inside of Cell

Action Potential Part 1 Read Facts 1-5 under on the big sheet as a group and answer question 1 You can model the movement of ions if needed, but for questions 3-5 wait for further directions In reading number 2, you can see a sodium channel opens. You can only move sodium ions through the sodium channels in the appropriate direction! Answer questions 3-5 after timing the movement of sodium ions

Action Potential Part 2 In reading number 6 you can see that a potassium channel opens, move the potassium in the appropriate direction through the potassium channel (for 3 seconds!) Answer questions 7-8 For number 9, don’t worry about the “try it” Answer questions 9-11

Action Potential Part 3 – Epilepsy Questions Work on these questions as a group!! If you are done, pick up the action potential article

Action Potential Steps 1. Neuron membrane maintains resting potential 2. Threshold stimulus is received 3. Sodium channels open 4. Sodium ions diffuse inward, depolarizing the membrane 5. Potassium channels open 6. Potassium ions diffuse outward, repolarizing the membrane 7. The resulting action potential causes a local bioelectric current that stimulates adjacent portions of the membrane. 8. Wave of action potentials travel the length of the axon as a nerve impulse * What does the word “adjacent” mean?

Exit Quiz Place the following images in the correct order & describe what happens in each of these steps A B Order of action potential (3-5 pictures) C