Describe how a simple Reflex works.

Reflexes allow you to respond to a stimuli (change in environment). A simple reflex begins with a receptor which are found in sense organs and allow you to detect the stimuli. An example of a sense organ is your skin and this contains receptors which allow you to detect temperature, pressure and pain. Once the receptor detects the change in stimuli, it sends out an electrical impulse across a nerve fibre known as the sensory neurone. The electrical impulse reaches a synapse at the end of the sensory neurone, where chemical information (neurotransmitters) are released. This is then picked up by a relay neurone (found in the spinal cord or brain) and carried as electrical impulses to a synapse and then to a motor neurone. The motor neurone carries the electrical impulses to effectors, which is either muscle or glands, which then respond to the stimulus by either contracting or releasing hormones respectively.