Homeostasis is the regulation of the conditions inside your body (and cells) to maintain a stable internal environment, in response to changes in both internal and external conditions
All of our automatic control systems are made up of 3 components that work together to maintain a steady condition:
Cells called receptors, coordination centres and effectors
What is a stimuli?
A change in your environment that you might need to respond to
A stimulus can be light, sound, touch, pressure, pain, chemical or a change in position or temperature
The receptors detect a stimuli when the level of something is too high or too low
They then send information to the coordination centre, which processes the information and organises a response from the effectors
The effectors respond to counteract the change- bringing the level back to its optimum
The mechanism that restores the optimum level is called a negativefeedbackmechanism
The nervous system is what allows you to react to your surroundings and to coordinate your behaviour
Receptors
The cells that detect stimuli
Many different types such as
Taste receptors in the tongue
Sound receptors in the ears
Smell receptors in the nose
Light receptors in the eyes
The central nervous system (CNS)
Where all the information from the receptors is sent and where reflexes and actions are coordinated
In vertebrates, this consists of the brain and spinalchord
Neurones transmit information as electrical impulses to and from the CNS
Effectors
Instructions from the CNS are sent along neurones to effectors
They are muscles or glands which respond to nervous impulses and bring about a response to stimulus
Respond to nervous impulses in different ways
Muscles contract
Glands secretechemical substances called hormones
Sensory neurones
Carry information as electrical impulses from the receptors to the CNS
Relay neurones
Carry electrical impulses from sensory neurones to motor neurones
Found in the CNS
Motor neurones
Carry lectrical impulses from the CNS to the effectors
