2. Coordination: The Nervous System
Learning Objectives:
- Understand that different cells and tissues
must work together in the nervous system
- To know the two systems of coordination in
mammals
- Know the structure and function neurones
3. Learning Flowchart:
Introduction to the How the nervous system
two parts of the works
nervous system Receptors + Density of touch
receptors exp
Sensory Neuron
function Effectors in the body
Nerve and Neuron
structure/function Video Summary
Picture Quiz
4. The Nervous System
What are its component
parts?
Central
• Brain Nervous
System
• Spinal cord
Peripheral Nervous
• Nerves System
What does it do?
• Enables you to control
your body
(Coordination)
• Gives you feedback
about the world
5. Look away if you’re squeamish…
A dissected
brain, spinal
cord and
sections of
major
nerves.
6. How the nervous system works
STEP 1: Receptors
Receptors are specialised cells. They can detect
changes in the environment (stimuli) and turn
them into electrical impulses.
Receptor Stimuli
Skin
Tongue
Nose
Eye
Ear
8. How the nervous system works
STEP 2:
A message is carried along a sensory neuron to
the CNS
9. How the nervous system works
STEP 3:
A message is sent from the CNS to an organ
(effector) via a motor neuron to carry out a
response
Examples:
• a muscle contracting to move the arm
• a muscle squeezing saliva from the salivary
gland
11. Nerves and Neurones
Nerves are collections of long thin nerve cells
called neurones
Dendrite – Collects
information from other
cells
Axon – Fibre which
carries information
Myelin Sheath –
Electrical insulation
Nodes of Ranvier – Allow rapid
conduction of impulses
12. Nerve Impulses
Messages pass along neurons in the form of
electrical impulses called action potentials
At the end of each neuron there is a tiny gap
which impulses cross in one direction this is
called a synapse
A chemical called neurotransmitter
diffuses across the gap
The nervous system of this zebrafish is shown in green. I don’t know how they did this!
(I don’t know why this image shows the pelvis – it isn’t part of the nervous system!) Ask students to discuss in groups what they think are the component parts of the nervous system. The brain and spinal cord make up the ‘central nervous system’ while the nerves comprise the ‘peripheral nervous system’. Students can then discuss what they think are the main functions of the nervous system before you reveal them.
The nervous system – brain, spine and nerves - is made up of very specialised cells called nerve cells or neurones (also spelt ‘neurons’). They have all the main features of animal cells: cell membrane, cytoplasm, nucleus, etc. – but also some very specialised features which allow them to do their particular job. The large blob towards the lower left seems to be the cell body of a neurone, with an axon branching off to the right.
