Nervous and hormone communication, CGP

Responding to their enviroment

• Animals increase their chances of suvival by responding to changes in thei external enviroment, e.g by avoiding harmful enviroments such as places that are too hot or too cold
• They also respond to changes in their internal enviroment to make sure that the conditions are always optimal for their metabolism
• Plants also increase their chances of survival by responding to changes in their enviroment
• Any change in the internal or external enviroment is called a stimulus

Receptors detect stimuli and effectors produce a response

• Receptors detech stimuli - they can be cells or proteins on cell surface membanes. There are loads of different types of receptors that detect different stimuli
• Effector are cells that bring about a response to a stimulus, to product an effect. Effectors include muscle cells and cells found in glands e.g pancreas
• Recepors communicate with effectors via the nervous system or the hormonal system or sometimes both

The nervous system sends information are electrical impulses

• The nervous system is made up of a complex netwok of cells called neurones. The three main types of neurone:
• Sensory neurones transmit electrical impulses from receptors to the central nervous system
• Motor neurones transmit electrical impulses from the CNS to effectors
• Relay neurones trasmit electical impulses between sensory neurones and motor neurons
• Stimulus is detected by receptor cells and an electrical impulse is sent along a sensory neurone
• When an electrical…