<p> Events at the Synapse</p><p>Directions: a. Insert your Regulations CD. b. Click the “Contents” button. c. Open the Nervous System File. d. Click Animations. e. Click Events at the Synapse.</p><p>Introduction</p><p>1. a. Where are synapses located? </p><p> b. What happens to “information” at the synapse? </p><p>Types of Synapses</p><p>Electrical Synapses</p><p>2. What is another name for electrical synapses? </p><p>3. What are connexons? </p><p>4. Where are gap junctions commonly found? </p><p>5. Name three advantages of gap junctions.</p><p> - </p><p> - </p><p> - </p><p>Chemical Synapses 6. What is the synaptic cleft? </p><p>7. Electrical impulses cannot jump the synaptic cleft. What is the role of neurotransmitters in achieving this task?</p><p>8. Explain what is meant by a chemical synapse being “one way only.” Neurotransmission at Chemical Synapses</p><p>9. An action potential arriving at the presynaptic membrane causes Ca+2 ions to flow through channels into the cytosol. What affect does this have on the vesicles containing neurotransmitters?</p><p>10. What do the neurotransmitter molecules do once they are released into the synaptic cleft?</p><p>11. Neurotransmitters cause postsynaptic ion channels to open. Explain how this can lead to either a graded potential or a hyperpolarization.</p><p>12. What causes an action potential to be generated? </p><p>Excitatory and Inhibitory Potentials</p><p>13. Opening postsynaptic sodium ion channels cause graded potentials in that membrane. Explain why these are referred to as Excitatory Postsynaptic Membrane Potentials (EPSPs).</p><p>14. Opening Cl- or K+ channels on the postsynaptic membrane will generate hyperpolarizations. Explain why these are referred to as Inhibitory Postsynaptic Membrane Potentials (IPSPs).</p><p>15. What influence do EPSPs and IPSPs have on whether or not an action potential will be generated at a neuron’s trigger zone? </p><p>Summation</p><p>16. Postsynaptic membrane potentials are summed (combined) and integrated at a neuron’s trigger zone. These membrane potentials come from thousands of synapses from the neuron’s dendrites. </p><p> a. Define spatial summation. </p><p> b. Define temporal summation. </p><p>17. IPSPs and EPSPs can combine to produce three possible outcomes. Describe what happens with each of the following.</p><p> a. Hyperpolarization </p><p> b. Sub-threshold graded potential </p><p> c. Threshold graded potential </p>