13.3 Sensory receptors Flashcards
what do chemoreceptors detect
chemicals
what do thermoreceptors detect
heat
what do mechanoreceptors detect
pressure
what do photoreceptors detect
light
what happens to a receptor when it detects a stimulus and how does it trigger an action potential
the permeability of its cell membrane changes which changes the charge difference across the membrane if the change in potential difference is large enough it will trigger and action potential in a sensory neurone
what is a receptor said to be charge wise when it’s not stimulated
it’s polarised
what are pacinian corpuscles what do they respond to changes in
they are receptors and respond to changes in pressure
where are pacinian corpuscles found
deep in skin
what’s the structure of pacinian corpuscles like
they consist of a single sensory neurone surrounded by layers of tissue which are separated by a gel
what type of sodium ion channels does the pacinian corpuscle contain and where are they found
they contain stretch mediated Na+ ion channels in the cell surface membrane
in the pacinian corpuscle what are the Na+ ion channels like under normal conditions and the what happens when pressure is applied and what happens
normally they are closed but when pressure is applied the channels become deformed and open allowing a rapid influx of sodium ions
what happens when there is a rapid influx of sodium ions
this makes the membrane potential in the sensory neurone less negative (depolarisation) producing a generator potential which can then produce an action potential
the pacinian corpuscle is a transducer what does this mean
Receptor cells are transducers – they convert energy in one form (such as light, heat or sound) into energy in an electrical impulse within a sensory neurone.
