What is homeostasis?
The maintenance of a constant internal environment.
What is a stimulus?
A change in environment.
What are receptors?
Cells that detect stimuli.
What are effectors?
Muscles or glands that respond to nerve impulses and bring about a response to a stimulus.
Give examples of three conditions in your internal environment that need regulating and maintaining.
- Body temperature
- Blood glucose levels
- Water content of the body
Briefly outline the stages the negative feedback system.
- Optimum level
- Level changes from optimum (stimulus)
- Receptors detect change
- Coordination centre receives and processes the information, organises the response
- Effectors respond
What do the coordination centres do?
Information is sent to them and they process this information and organise a response from the effectors. The coordination centres include the brain, spinal cord and pancreas.
What is the nervous system?
A communication system that allows you to react to your surroundings (and coordinate your behaviour).
What is the central nervous system (CNS) made up off?
Brain and spinal cord.
What is the CNS?
Where all the information from the receptors is sent, and where reflexes and actions are coordinated.
What is the nervous system made up off?
Brain, spinal cord and nerves.
In what ways do muscles and glands respond to nervous impulses?
- Muscles contract
- Glands secrete hormones
What do neurones do?
Involved in the transfer of information to and from the CNS.
Name the three neurones.
- Sensory neurones
- Relay neurones
- Motor neurones
What do the sensory neurones do?
Carry information (as electrical impulses) from the receptors in the sense organs to the CNS.
What do the relay neurones do?
Carry electrical impulses from sensory neurones to motor neurones - found in the CNS.
What do the motor neurones do?
Carry electrical impulses from the CNS to the effectors.
Draw a flow diagram showing the transmission of information to and from the CNS.
relay
neurone
stimulus > Receptors > CNS > Effector > response
sensory motor
neurone neurone
