Receptors

Receptors are specific....

• only detect 1 particular stimulus.
• some receptors are cells e.g. photoreceptors.
• some receptors are proteins on cell surface membranes e.g. glucose receptors.

Pascinian Corpuscles:

• mechanorepectors- pick up mechanical stimuli e.g. pressure.
• contain en of a sensory neurone wrapped in layers of lamellae.
• Pressure squashes the lamellae & presses on the neurone ending.
• Sodium channels open, sodium diffuses into cell, & a generator potential is produced.
• If this gets to be larger than the threshold value, an action potential is produced.

EYES:

• Light enters eye through pupil (iris muscles control the amount let through).
• The lens focuses the rays onto the retina at the back of the eye.
• The…