a specialised cell which detects changes in our external environment called stimuli
sensory receptors work by converting a particular form of energy into a form of electrical energy called an action potential
since sensory receptors convert one form of energy into another form they are termed transducers
what's the role of a chemoreceptor
to detect chemicals in substances we taste or smell
what's the role of a photoreceptor
to detect light rays
what's the role of a thermoreceptor
detect changes in temperature
what do mechanoreceptors do
detect pressure movements and vibrations
what's the role of electroreceptors
detect electrical fields and colours mainly in fish
for an action potential to be initiated in a receptor the generator potential has to reach a certain threshold value (-55mV). once this value is reached then more Na+ will continue to diffuse into the membrane so causing further depolarisation. at +40mV an action potential will be set up.
