6.5 Neurons and synapses

IB Syllabus Statements

Understandings:

Neurons transmit electrical impulses.
The myelination of nerve fibres allows for saltatory conduction.
Neurons pump sodium and potassium ions across their membranes to generate a resting potential.
An action potential consists of depolarization and repolarization of the neuron.
Nerve impulses are action potentials propagated along the axons of neurons.
Propagation of nerve impulses is the result of local currents that cause each successive part of the axon to reach the threshold potential.
Synapses are junctions between neurons and between neurons and receptor or effector cells.
When presynaptic neurons are depolarized they release a neurotransmitter into the synapse.
A nerve impulse is only initiated if the threshold potential is reached.

Applications and skills:

Application: Secretion and reabsorption of acetylcholine by neurons at synapses.
Application: Blocking of synaptic transmission at cholinergic synapses in insects by binding of neonicotinoid pesticides to acetylcholine receptors.
Skill: Analysis of oscilloscope traces showing resting potentials and action potentials.

Give an example of cooperation and collaboration between groups of scientists.
Outline how neurons transmit electrical impulses.
Explain the role of myelination of nerve fibers.
Explain how a resting potential is generated.
What does an action potential consist of?
Define nerve impulses.
Explain how nerve impulses are initiated and propagated.
What are synapses?
Explain what happens when presynaptic neurons are depolarized.
Outline the secretion and reabsorption of acetylcholine by neurons at synapses.
Explain how synaptic transmission at cholinergic synapses is blocked in insects. Use the terms neonicotinoid pesticides and acetylcholine receptors.
How you would analyze oscilloscope traces showing resting potentials and action potentials.
What has been a benefit of understanding the workings of neurotransmitters and synapses?