13.3 sensory receptors

5.1.3

what do sensory receptors convert

convert stimulus they detect into a nerve impulse

what are transducers

convert a stimulus into a nerve impulse (generator potential)

what are two features of sensory receptors

• specific to single type of stimulus

• act as transducer

what are four types of sensory receptors and what are their stimuli

• mechanoreceptors (pressure and movement)

• chemoreceptor (chemicals)

• thermoreceptor (heat)

• photoreceptors (light)

where are pacinian corpuscles located

deep within skin and most abundant in fingers and soles of feet

what type of sensory receptor are pacinian corpuscles

mechanoreceptors

where is the end of the sensory neurone in a pacinian corpuscle

within the centre of the corpuscle

what surrounds the end of the sensory neurone in a pacinian corpuscle

layers of connective tissue, each layer separated by a layer of gel

what is a stretch-mediated sodium channel

a special type of sodium channel that when shape is changed, permeability to sodium increases

what is the resting state in a pacinian corpuscle

stretch-mediated sodium ion channels are closed - has a resting potential

what does it mean when a membrane is depolarised

inside of cell becomes less positive due to influx of positive sodium ions - result in generator potential

what is a generator potential

local change in the membrane potential of a sensory receptor

what does a generator potential do

created an action potential if threshold is passed (-55mV)

where will the action potential be transmitted from a pacinian corpuscle

transmitted along neurone to CNS