The Nervous System

A neurone is a nerve cell that has a cell body with thin fibres that carry electrical impulses. 

Groups of neurones create the nervous system, which is the CNS (central nervous system) the brain and spinal cord and the peripheral nervous system that is the nerves conneting sense organs with the CNS. 

Receptors detect stimuli and convert them into electrical impulses and send them along neurones. 

Sensitivity depends on the number of receptors in an area and the force on the skin. 

Photoreceptors detect light. Thermoreceptors detect temperature. 

Sensory neurones send impulses from receptors in the sense organs to the CNS. Has a cell body and dendrites (thin branches). Short axon (fibre that carries impulses). 

Motor neurones send impulses from the CNS to the muscles/glands. Has a cell body and dendrites. Long axon.