13.3 Sensory receptors

Question 1

what do sensory neurones do?

Answer 1

act as transducers by converting a stimulus into a nerve impulse

Question 2

what does a Pacinian corpuscle detect?

Answer 2

mechanical pressure

Question 3

what is the structure of a Pacinian corpuscle?

Answer 3

Question 4

what is special about the Na+ channels in a Pacinian corpuscle?

Answer 4

they are stretch mediated meaning that they change shape when there is a pressure change, causing a change in the permeability to sodium

Question 5

how does mechanical pressure lead to an electrical impulse?

Answer 5

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