The Nervous System

SENSE ORGANS DETECT STIMULI your sense organs contain receptors (groups of cells that are sensitive to stimulus, they change stimulus energy such as light energy into electrical impulses

The EAR is a SENSE ORGAN it contains SOUND RECEPTORS

The central nervous system is where information from the sense organs is sent and where actions are coordinated. This consists of the BRAIN AND SPINAL CORD.

EYES - LIGHT RECEPTORS - SENSITIVE TO LIGHT - HAVE A NUCLEUS CYTOPLASM AND CELL MEMBRANE (JUST LIKE MOST ANIMAL CELLS)

NOSE - SMELL RECEPTORS - SENSITIVE TO CHEMICAL STIMULI

TOUNGUE - TASTE RECEPTORS - SENSITIVE TO SALTY, SWEET ETC - CHEMICAL STIMULI

SKIN - SENSITIVE TO TOUCH, PREASSURE, PAIN AND TEMPURATURE CHANGE

Sensory neurones - the nerve cells that carry signals as electrical impulses from the receptors in the receptors in the sense organs to the central nervous system 

 Relay neurones - the nerve cells that carry signals from sensory neaurones to motor neurones

Motor neaurones - the nerve cells that carry signals from the CNS to the effector muscles or glands

Effectors - muscles and glands that respond in different ways. Muscles contract in response to nervous impulse where as glands secrete hormones.

RECEPTORS > SENSORY NEURONES > CNS > RELAY NEURONES > MOTOR NEURONES > EFFECTORS