The Nervous System – Lesson Summary

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Learning Objective

In this lesson we will learn about the structure and function of the nervous system.

Learning Outcomes

By the end of this lesson you will be able to:

  • Describe the general function of the nervous system.
  • Describe the basic structure of neurons and the function of the three main types.
  • Explain how nerve signals are transferred between neurons.
  • Differentiate between the central nervous system and the peripheral nervous system and describe their respective functions.
  • Describe what a reflex arc is and explain how it enables rapid responses.

 
the nervous system lesson contents

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Lesson Topics

1 | Overview of the Nervous System

2 | Structure of Neurons

3 | Types of Neurons

4 | Synapses and Neurotransmitters

5 | Organisation of the Nervous System

6 | The Central Nervous System

7 | The Peripheral Nervous System

8 | The Reflex Arc

9 | Summary

Lesson Summary

  • The primary function of the nervous system is to monitor and respond to environmental changes.
  • The nervous system is composed of nerve cells (neurons) which transmit electrical signals called nerve impulses.
  • All nerve cells have three main components:
  • Cell body – contains the nucleus and other cell organelles.
  • Dendrites – receive nerve impulses from other nerve cells.
  • Axon – sends nerve impulses to other nerve cells.
  • Many axons and some dendrites are surrounded by an insulating layer called a myelin sheath.
  • There are three functional types of nerve cells:
  • Sensory neurons – detect changes in the environment.
  • Motor neurons – effect a response in a muscle or gland.
  • Interneurons – connect sensory neurons and motor neurons.
  • A synapse is a small gap separating adjacent neurons.
  • Neurotransmitters are molecules that carry a chemical signal across a synapse.
  • The central nervous system (CNS) consists of the brain and the spinal cord.
  • It interprets sensory information and dictates responses.
  • The peripheral nervous system (PNS) consists of all the nervous tissue that links the central nervous system to the rest of the body.
  • It consists of sensory neurons, which detect changes, and motor neurons, which effect a response.
  • Voluntary responses are carried out by the somatic nervous system.
  • Involuntary responses are carried out by the autonomic nervous system.
  • These include ‘fight or flight’ responses, which are controlled by the sympathetic nervous system, and ‘rest and digest’ responses, which are controlled by the parasympathetic nervous system.
  • A reflex is a rapid, automatic response, in which a particular stimulus always causes the same motor response.
  • It occurs via a reflex arc to and form the spinal cord, bypassing the brain.

 
overview of the nervous system

(Header image: Giovanni Cancemi, Adobe Stock)