Biology 1 - The Nervous System

The Nervous System

Sense organs detect stimuli

• You have 5 different sense organs: eyes, ears, tongue, skin and nose.
• They all contain different receptors. Receptors are a group of cells which are sensitive to a stimulus. They change stimulus energy to electrical impulses.
• A stimulus can be light, sound, chemical, touch, pressure, pain, change of position or temperature. 

1) Eyes

• Light receptors - sensitive to light. These cells have a nucleus, cytoplasm and a cell membrane like most animal cells.

2) Ear

• Sound receptors - sensitive to sound. 
• Balance receptors - sensitive to change in position.

3) Nose

• Smell receptors - sensitive to chemical stimuli.

4)…