DP Biology (last assessment 2024)
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6.5 Neurons and synapses

Description

Nature of science:
Cooperation and collaboration between groups of scientists—biologists are contributing to research into memory and learning. (4.3)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.

Guidance:

  • The details of structure of different types of neuron are not needed.
  • Only chemical synapses are required, not electrical, and they can simply be referred to as synapses.

Utilization:

  • An understanding of the workings of neurotransmitters and synapses has led to the development of numerous pharmaceuticals for the treatment of mental disorders.

Syllabus and cross-curricular links:
Biology
Topic 1.4 Membrane transport
Chemistry
Topic C6 Electrochemistry, rechargeable batteries and fuel cells
Psychology
Core: Biological level of analysis

Aims:

  • Aim 8: The social effects of the abuse of psychoactive drugs could be considered, as could the use of the neurotoxin Botox for cosmetic treatments.

 

Directly related questions

Sub sections and their related questions

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