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Nervous System

Human Biology (Year 12) - Nervous Transmission

Ben Whitten

The nervous system is the communication system and control centre of the body. With the endocrine system, it maintains a constant internal environment within the body. It is composed of two divisions;

  • The Central Nervous System (CNS) which is made up of the brain and spinal cord

  • The Peripheral Nervous System (PNS)

The nervous system is comprised of many roles.

  • Has receptors to detect stimuli (changes to the internal and external environment)

  • Transmits nerve impulses from receptors to the brain

  • Analyses sensory input from different receptors

  • Stores information (memory)

  • Integrates information

  • Transmits nervous impulses from the brain to muscles and glands in order to respond to stimuli

What are neurons?

Image: Neuron image, Image by Dhp1080, Sourced Under a Creative Commons 4.0 License from Wiki Commons Neurons or nerve cells are the anatomical and functional units of the nervous system; they are the only part of the body that conducts nerve impulses. There are three key components to a neuron;

  • Cell body – The cell body consists of a mass of neuroplasm surrounding the nucleus; it contains the nucleus and directs the activities of the rest of the cell – the axon and dendrites extend from the cell body

  • Dendrite – The dendrite is a branching structure, and acts to carry nerve impulses towards the cell body, referred to as an afferent process

  • Axon – The axon is typically long and less branching; it acts to carry nerve impulses away from the cell body, known as the efferent process

What are the other components of neurons?

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