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.
What is this lesson about?
Coordination: The Nervous SystemLearning 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
Learning Flowchart:Introduction to the How the nervous systemtwo parts of the worksnervous system Receptors + Density of touch receptors exp Sensory Neuron function Effectors in the body Nerve and Neuron structure/function Video SummaryPicture Quiz
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
Look away if you’re squeamish… A dissected brain, spinal cord and sections of major nerves.
How the nervous system worksSTEP 1: ReceptorsReceptors are specialised cells. They can detect changes in the environment (stimuli) and turn them into electrical impulses. Receptor Stimuli Skin Tongue Nose Eye Ear
Density of touch receptors Experiment End www.A6training.co.uk
How the nervous system worksSTEP 2:A message is carried along a sensory neuron to the CNS
How the nervous system worksSTEP 3:A message is sent from the CNS to an organ (effector) via a motor neuron to carry out a responseExamples:• a muscle contracting to move the arm• a muscle squeezing saliva from the salivary gland
Nerves and NeuronesNerves are collections of long thin nerve cells called neurones Dendrite – Collects information from other cells Axon – Fibre which carries informationMyelin Sheath –Electrical insulation Nodes of Ranvier – Allow rapid conduction of impulses
Nerve ImpulsesMessages pass along neurons in the form of electrical impulses called action potentialsAt the end of each neuron there is a tiny gap which impulses cross in one direction this is called a synapseA chemical called neurotransmitterdiffuses across the gap