Lesson - Neurons

Lesson Objectives

General Overview:

Nerves transmit electrical impulses to various parts of the body. The structure and function of neurons are specific are specific to this task. This lesson will look at the formation of an action potential and who the potassium and sodium ions are pumped across the neuron membrane to promote this process. The final part of this lesson will look at the function of a synapse and how the electrical signal is passed from one neuron to the other.

Syllabus Statements:

1. Neurons transmit electrical impulses.

2. The myelination of nerve fibres allows for saltatory conduction.

3. Neurons pump sodium and potassium ions across their membranes to generate a resting potential.

4. An action potential consists of depolarization and repolarization of the neuron.

5. Nerve impulses are action potentials propagated along the axons of neurons.

6. Propagation of nerve impulses is the result of local currents that cause each successive part of the axon to reach the threshold potential.

7. Synapses are junctions between neurons and between neurons and receptor or effector cells.

8. When presynaptic neurons are depolarized they release a neurotransmitter into the synapse.

9. A nerve impulse is only initiated if the threshold potential is reached.

10. Application: Secretion and reabsorption of acetylcholine by neurons at synapses.

11. Application: Blocking of synaptic transmission at cholinergic synapses in insects by binding of neonicotinoid pesticides to acetylcholine receptors.

12. Skill: Analysis of oscilloscope traces showing resting potentials and action potentials.

13. Structure and function of the sodium-potassium pumps for active transport and potassium channels for facilitated diffusion in axons