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neurons nerve impulses

A LevelBiology~5 min read

Overview

This lesson explores the fundamental units of the nervous system, neurons, and the electrical signals they transmit, known as nerve impulses or action potentials. We will delve into the structure of different neuron types, the mechanism of nerve impulse generation and propagation, and the role of the resting potential.

Structure and Types of Neurons

Neurons are highly specialized cells that form the basis of the nervous system. A typical neuron consists of three main parts: * **Cell body (soma):** Contains the nucleus and other organelles, responsible for metabolic activities. * **Dendrites:** Short, branched extensions that receive incomin...

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Key Concepts

  • Neuron: The basic structural and functional unit of the nervous system, specialized for transmitting electrical and chemical signals.
  • Action Potential: A brief, rapid, and reversible change in the electrical potential across a neuron's membrane, constituting a nerve impulse.
  • Resting Potential: The stable, negative electrical potential across the membrane of an unstimulated neuron, maintained by ion pumps and differential permeability.
  • Depolarisation: A decrease in the negativity of the resting potential, making the inside of the neuron less negative or even positive.
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Exam Tips

  • Be able to draw and label a typical neuron, identifying dendrites, cell body, axon, myelin sheath, and Nodes of Ranvier.
  • Clearly explain the roles of the Na+/K+ pump, differential membrane permeability, and negatively charged organic molecules in establishing and maintaining the resting potential.
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