the nervous system b1

What is this lesson about?

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

Learning Flowchart:

Introduction to the two parts of the nervous system

Sensory Neuron function

How the nervous system worksReceptors + Density of touch receptors exp

Effectors in the body

Nerve and Neuron structure/function Video Summary

Picture Quiz

The Nervous System

• Brain• Spinal cord• Nerves

• Enables you to control your body (Coordination)

• Gives you feedback about the world

What does it do?

What are its component parts?

Central Nervous System

Peripheral Nervous System

Look away if you’re squeamish…

A dissected brain, spinal cord and sections of major nerves.

How the nervous system works

STEP 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

www.A6training.co.uk

Density of touch receptors Experiment

End

How the nervous system works

STEP 2: A message is carried along a sensory neuron to

the CNS

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

The Cells of the Nervous System - Neurones

Nerves and NeuronesNerves 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

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 neurotransmitterdiffuses across the gap

http://www.brainpop.com/health/bodysystems/nervoussystem/

Effector, Receptor or Neurone

Effector, Receptor or Neurone

Effector, Receptor or Neurone

Effector, Receptor or Neurone

Effector, Receptor or Neurone

Effector, Receptor or Neurone