1. Do Now Complete Part 1 on your worksheets with a partner. A problem for you to solve: – Given that you know the axon sends signals electrically, and that the synapse sends signals chemically, how would you change the electrical signal of the axon into a chemical signal at the synapse? – Brainstorm mechanisms to solve this problem with a partner.

2. From Electrical Signal to Chemical Signal Chemical Signal Electrical Signal

3. Synaptic Transmission Electrical Signal

4. Synaptic Transmission

5. The Stage: Presynaptic cell Synaptic Cleft Postsynaptic Cell

6. The Characters: Voltage-gated Ca 2+ channels Synaptic vesicles Neurotransmitters (NT) Receptors Action Potential Reuptake Transporters Ca 2+ sensitive proteins

7. How do the characters work together to complete synaptic transmission? Complete Part 2 of your worksheets with a partner.

8. The Play: 1. Action Potential

9. The Play: 1. Action Potential Ca 2+ 2. Voltage-gated Ca 2+ channels open. Ca 2+ flows into cell

10. The Play: 1. Action Potential Ca 2+ 2. Voltage-gated Ca 2+ channels open. Ca 2+ flows into cell 3. Ca 2+ sensitive proteins fuse synaptic vesicles to membrane, releasing NTs into synaptic cleft

11. The Play: 1. Action Potential Ca 2+ 2. Voltage-gated Ca 2+ channels open. Ca 2+ flows into cell 4. NTs bind to postsynaptic receptors. 3. Ca 2+ sensitive proteins fuse synaptic vesicles to membrane, releasing NTs into synaptic cleft

12. The Play: 1. Action Potential Ca 2+ 5. Ion channels open on postsynaptic membrane, allowing ions to flow into cell. 2. Voltage-gated Ca 2+ channels open. Ca 2+ flows into cell 4. NTs bind to postsynaptic receptors. 3. Ca 2+ sensitive proteins fuse synaptic vesicles to membrane, releasing NTs into synaptic cleft

13. The Play: 1. Action Potential 2. Voltage-gated Ca 2+ channels open. Ca 2+ flows into cell Ca 2+ 4. NTs bind to postsynaptic receptors. 5. Ion channels open on postsynaptic membrane, allowing ions to flow into cell. 6. Excess NTs are degraded by enzymes or pumped back into presynaptic cell. 3. Ca 2+ sensitive proteins fuse synaptic vesicles to membrane, releasing NTs into synaptic cleft

14. The Play: 1. Action Potential 2. Voltage-gated Ca 2+ channels open. Ca 2+ flows into cell Ca 2+ 4. NTs bind to postsynaptic receptors. 5. Ion channels open on postsynaptic membrane, allowing ions to flow into cell. 6. Excess NTs are degraded by enzymes or pumped back into presynaptic cell. 3. Ca 2+ sensitive proteins fuse synaptic vesicles to membrane, releasing NTs into synaptic cleft

15. Does it matter which ions flow into the cell? Sodium (Na + )Calcium (Ca 2+ )Chloride (Cl - ) Positive Negative

17. Synaptic Transmission Ca 2+