Sensory receptors and stimuli
Sensory receptors (eye, ear, skin, nose and tongue) allow an individual's body to be informed about the state of its environment. They therefore react to what is called a stimulus, i.e. the changes that occur in the environment and that are perceptible by a sensory receptor.
The sensory circuit
The sensory circuit traversed by the nerve impulse is always the same, regardless of the stimulus that will be at the origin of it. It all starts with the stimulus that will be picked up by a sensory receptor. A transformation occurs in order to change the stimulus into nerve impulses. Subsequently, the impulse travels through a conductor (a sensory neuron for example) to the brain, where the impulse will be analyzed. The sensory receptors are scattered throughout the body in order to intercept messages from the environment (stimulus), whether mechanical, chemical, light or thermal. They are mainly found in the sense organs.
