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Topic 6.5 Reading Guide

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Topic 6.5 Reading Guide Name _______________________________________________________________ Period ______ Date ____________ Topic 6.5 Neurons and Synapses 6.5.U1 Neurons transmit electrical impulses. 1. State the function of the nervous system and it’s functional units, neurons. 2. Draw a diagram of a neuron 3. Annotate your diagram of a neuron cell with the name and function of the dendrites, axon and cell body. 6.5.U2 The myelination of nerve fibers allows for saltatory conduction. 4. Outline the function of myelin. 5. Annotate the micrograph of a myelinated axon. Electron Microscope Facility, Trinity College 6. State the role of Schwann cells in formation of myelin. 7. Outline the mechanism and benefit of saltatory conduction. 8. Compare the speed of nerve impulse conduction myelinated and non-myelinated neurons. 6.5.U3 Neurons pump sodium and potassium ions across their membranes to generate a resting potential. 9. Define resting potential. 10. Explain what is meant by the term antiport. 11. Explain three mechanisms that together create the resting potential in a neuron. 12. State the voltage of the resting potential. 6.5.U4 An action potential consists of depolarization and repolarization of the neuron. 13. Define action potential, depolarization and repolarization. 14. Outline the mechanism of neuron depolarization. 15. Outline the mechanism of neuron repolarization. 6.5U5 Nerve impulses are action potentials propagated along the axons of neurons. 16. Define nerve impulse. 17. Compare resting and action potential. 18. State the two phases that the action potential consists of. 19. Describe how nerve impulses are propagated along the neuron axon. 20. Outline the cause and consequence of the refractory period after depolarization. 6.3.S1 Analysis of oscilloscope traces showing resting potentials and action potentials. 21. Outline the use of oscilloscopes in measuring membrane potential. 22. Annotate an oscilloscope trace to show the resting potential, action potential (depolarization and repolarization), threshold potential and refractory period. Cambridge University Press 6.5.U6 Propagation of nerve impulses is the result of local currents that cause each successive part of the axon to reach the threshold potential. 23. Explain how the movement of sodium ions propagates an action potential along an axon. 24. Explain movement of sodium ions in a local current. 25. Describe that cause of and effect of membrane potential reaching the threshold potential. 6.5.U7 Synapses are junctions between neurons and between neurons and receptors or effector cells. 26. Define the terms synapse, synaptic cleft and effector. 27. State the roles of neurotransmitters in nervous communication. 6.5.U8 When presynaptic neurons are depolarized they release a neurotransmitter into the synapse. AND 6.5.U9 A nerve impulse is only initiated if the threshold potential is reached. 28. Outline the mechanism of synaptic transmission, including the role of depolarization, calcium ions, diffusion, exocytosis, neurotransmitters, receptors, sodium ions, sodium channels, threshold potential and action potential. 29. Explain, with reference to the threshold potential, why not all releases of neurotransmitters into the synapse lead to an action potential in the postsynaptic neuron. 6.5.A1 Secretion and reabsorption of acetylcholine by neurons at synapses. 30. Outline the formation, secretion and action of acetylcholine. 31. Outline how acetylcholine is broken down and it’s products reabsorbed. 32. Suggest a consequence of acetylcholine not breaking down. 6.5.A2 Blocking of synaptic transmission at cholinergic synapses in insects by binding of neonicotinoid pesticides to acetylcholine receptors. 33. Define cholinergic synapse. Outline the mechanism of action of neonicotinoids use as insecticides. 34. Compare the proportion of cholinergic synapses in insects and humans. 35. State why neonicotinoids insecticides are not highly toxic to humans. .
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