13.3 Sensory receptors Flashcards
what do sensory neurones do?
act as transducers by converting a stimulus into a nerve impulse
what does a Pacinian corpuscle detect?
mechanical pressure
what is the structure of a Pacinian corpuscle?
what is special about the Na+ channels in a Pacinian corpuscle?
they are stretch mediated meaning that they change shape when there is a pressure change, causing a change in the permeability to sodium
how does mechanical pressure lead to an electrical impulse?
at resting, the Na+ channels are not stretched so Na+ ions cannot move in
when pressure is applied Na+ channels are stretched which allows Na+ to diffuse into the neurone
Na+ ions moving in causes the membrane to depolarise
the generator potential creates an action potential which passes along the sensory neurone
