Sensory Receptor Cells
- A cell that responds to a stimulus is called a receptor cell
- Receptor cells are transducers – they convert energy in one form (such as light, heat or sound) into energy in an electrical impulse within a sensory neurone
- Receptor cells are often found in sense organs (eg. light receptor cells are found in the eye)
- Some receptors, such as light receptors in the eye and chemoreceptors in the taste buds, are specialised cells that detect a specific type of stimulus and influence the electrical activity of a sensory neurone
- Other receptors, such as some kinds of touch receptors, are just the ends of the sensory neurones themselves
- When receptors cells are stimulated they are depolarised
- If the stimulus is very weak, the cells are not sufficiently depolarised and the sensory neurone is not activated to send impulses
- If the stimulus is strong enough, the sensory neurone is activated and transmits impulses to the CNS
