2. In order to live and interact with our world, we need
to have ways of getting information

3. Sensing danger

4. Avoiding Damage

5. We need to be able
to
collect
information, proce
ss it
and
respond to it.

6. Getting Around

7. We have sense organs
 Skin
 Eyes
 Ears
 Taste buds
 Nose

8. These collect a multitude of information so we can
understand and interact with our world

9. Some senses cause an instant response

10. Senses are picked up by receptors
 Chemoreceptors sense chemicals (smell, taste)
 Nociceptors sense pain
 Mechanoreceptors sense pressure , light touch & stretch
 Thermoreceptors sense temperature changes
 Photoreceptors sense light and shadow and colours

11. Sensory Nerves
Sensory receptors start electrical
impulses along sensory nerve
fibres to be processed.
The cell body decides how to
respond, sending impulses
 to other neurons to cause an
effect (Right) – reflex action
 to alert the conscious brain
to the stimulus.

12. Sensory Neuron Structure
Receive input from a receptor OR from another
neuron at the dendrites
Pass the message to the cell body and then down the
axon to pass the message on to other neurons.

13. Peripheral Nerves
Dendrites receive
information
Cell body manages
information
Axon conducts signal
ultra fast because of
myelin sheath
Terminal buds
interact with another
nerve cell dendrites or
effector organ eg
muscle

14. Sensory Motor Reflex
Signal sent
to
interneuron
receptor
• Passes message
to motor nerve
• Simultaneous
message sent to
brain
interneuron
• Signal to muscle
• Muscle
contraction
Motor
nerve

15. Nervous System
The Rapid Response System for stimuli that require
immediate action that is short lasting and has no
permanent change on the body

16. Endocrine System
Sometimes the body needs a longer lasting response
that the nervous system cannot coordinate
This is where chemical messages, called hormones play
a role in controlling body systems
The endocrine system controls the release of hormones

17. Hypothalamus – receives information
about internal body and sends
messages to glands to in response
Pineal Gland – manages day/night
cycle
Pituitary Gland – master control
Thyroid/Parathyroid Gland – controls
metabolism
Thymus Gland
Adrenal Gland – fight and flight
response
Pancreas – controls digestive enzymes
and insulin
Ovary/Testes – controls sexual cycles

18. Hormones
Insulin in the Pancreas
 Released in response to
sugar levels in the blood
 Acts to store the excess
sugar in cells for later use
when needed
 Glucagon is the opposite
acting hormone and
releases sugars when
blood sugars are low

19. Adrenal Glands
 Near the kidneys, the adrenal glands act when a body is
under stress
 Release of adrenaline
 Increased heart rate
 Increases blood flow to the muscles
 Increase blood pressure
 Increase metabolic rate

20. Hormones
Are often in the blood at varying concentrations.

21. Hormones
Act slowly
 Seconds - adrenal
 Minutes- pancreas
 Hours, days, months, years – sex hormones
Long lasting response that may be reversible or not

22. Summary of Control Systems
 Via 2 systems (fast and slow)
 Keeps the body at optimum function
 HOMEOSTASIS – the state of the body
is kept within normal parameters, eg
blood sugar, blood pH, temperature of
the body