The nervous system

1
The nervous system
2
Recap The nervous system

• Main Function
• This communication system controls and
  coordinates functions throughout the body and
  responds to internal and external stimuli.

Our nervous system allows us to feel pain.
3
Recap Nervous system

• It consists of 2 parts
• The central nervous system consists of the brain,
  spinal cord (CNS),
• The peripheral nervous system contain the other
  nerves and receptors of our body.

4
Notes Sympathetic nervous system

• Speeds up functions of the body
• Prepares body for emergencies
• Makes body alert and ready to act
• Diverts blood away from digestive tract
• Stops peristalsis
• Opens bronchioles more oxygen
• Increases heart rate
• Dilates pupil more light
• Increase blood flow to heart

5
Notes Para-sympathetic nervous system

• Slows everything down
• In control when you are resting
• Increases blood flow to digestive tract
• Stimulates salivary galnds
• Reduces bronciole diameter- less oxygen
• Controls heart beat
• Reduces diameter of pupil

6
Notes How is information transmitted?

• Information passes from receptors along nerve
  cells called neurones.
• Nerve cells are long and thin to carry messages
  called impulses.

Cell body
Dendrites
Myelin sheath
nucleus
Axon
7
(No Transcript)
8
Task Draw a neuron

1. Cell body contains nucleus most of the
   cytoplasm
2. Dendrites projections that bring impulses into
   the neuron to the cell body.
3. Axon long projection that carries impulses away
   from cell body

9
Notes There are 3 types of neurone

1. Sensory neurone carry impulse from receptor to
   CNS
2. Relay connects sensory to motor
3. Motor connects CNS to effector which makes a
   response. (muscle, gland)

10
Reflex Arc
A reflex is an involuntary response that is
processed in the spinal cord not the
brain. Reflexes protect the body before the brain
knows what is going on.
11
Reflex response Draw flow of signal
Stimulus gtgt receptorgtgt sensory gtgt co ordinator
(spinal cord) gtgt motor gtgt Effector gtResponse


12
Neurotransmitters

• Neurotransmitters are chemicals that transmit
  signals from a neuron to a target cell across a
  synapse (gap)

13
Define Neuro-transmitter

• Because neurons never touch, chemical signalers
  called neurotransmitters must travel through the
  space called synapse between two neurons.

Neurotransmitters
(pink spheres)
The message is transferred when RECEPTORS receive
neurotrans-mitters.
Synapse (gap)
14
Neurotransmitters
15
Ruler drop test

• Aim
• Variables
• Hypothesis
• Materials
• Procedure
• Safety
• Data table

16
Ruler drop test

• Graph comparison of response in your group
• Analyse numbers etc
• Conclusion of findings
• Evaluation

17
Analysis questions to consider

• 1. What happened to .. reaction time as he
  had more tries?
• 2. What happened to . reaction time as she
  had more tries?
• 3. Who improved the most from the first to the
  fifth try?
• 4. Who had the fastest reaction time?
• 5. What do you think might happen if .. has
  more tries?
• 6. What have you found out about reaction time so
  far?
• 7. What else would you like to find out about
  reaction time?

18
What might we be able to find out from our
investigation?

• Who has the fastest reaction time in the class?
• Do boys have better or worse reaction times than
  girls?
• Do sporty people have the fastest reaction times?
• Do people who play video games have the fastest
  reaction times?
• Does the oldest person in the class have the
  fastest reaction time?
• Do children have faster reaction times than grown
  ups?
• If you try the reaction test every day for a week
  will your reaction time improve?