1. The nervous system

2. Learning objectives
Identify the key parts of the central nervous system
(CNS)
Explain the function of each part of the CNS
Explain how the CNS helps humans to react to there surroundings

3. The nervous system The nervous system is made up of three main parts:
the brain,the spinal cord and nerve fibres.
It detects stimuli such as light,temperature, sound, pressure, pain,movement, touch and chemicals (for example, food) and co-ordinates the body’s response.
If you smell something burning your nose sends a message to your brain, and it co-ordinates your response.
Q1) Look at photograph:Explain, in detail what happens the moment the starter fires the gun.

4. Answer Q1

5. Diagram of nervous system

6. The nervous system - Receptors
Receptors are sensors on the body that detect stimuli.
Information from these passes along nerve fibres to the brain.
Nerve fibres are made from lots of nerve cells, called neurones.
The information passes along them as electrical signals called impulses.

7. A Neurone

8. Types of Neurone Sensory neurones Relay neurones Motor neurones
An effector can be a muscle that is made to contract (tighten) or a gland that releases (secretes) a chemical (for example, a hormone).

9. Task 2: Label the function of each part of the nervous system

10. Takes impulses from the sense organ to the relay neurone.
Where the relay neurones are found.
Receives impulses from the spinal cord and sends out new impulses.
Takes impulses to the brain and from the brain.
The muscle that receives the impulse from motor neurone
Takes impulses from the relay neurone to the effector.
Senses stimuli from our surroundings.

11. Task 3: Write down the path of the impulse from when the athlete hears the starting pistol

12. Reflexes; The Grabbing Game
Who is the best?
Why are they the best?
What stimuli is making you react?
What do we call the time it takes to grab the paper?

13. Reflex Action

14. Describe a reflex action

15. Pupil in the eye shrinks
Reflexes are automatic actions that we cannot control.They are used to protect our body from injury. Complete the table below by filling in the missing boxes.
Reflex
Protection given
to eye
stops us from choking
Sneezing
Pupil in the eye shrinks

16. Learning objectives – What have I learnt
Identify the key parts of the central nervous system
(CNS)
Explain the function of each part of the CNS
Explain how the CNS helps humans to react to there surroundings

17. Diagram of nervous system

18. Types of Neurone
Sensory neurones carry impulses from the receptor to the spinal cord.
Relay neurones carry impulses through the spinal cord and up to the brain and from the brain back along the spinal cord.
Motor neurones take impulses from the spinal cord to an effector.
An effector can be a muscle that is made to contract (tighten) or a gland that releases (secretes) a chemical (for example, a hormone).