Module 5: Sensory receptors Flashcards
All sensory receptors have two main specific features , what are they?
-they are specific to a single type of stimulus
-they act as a transducer
What is meant by a transducer
they convert a stimulus into a nerve impulse
The nervous impulse that is created is known as a …
generator potential
What are the 4 main types of sensory receptors in animals
What kind of stimulus do they detect?
mechanoreceptors-pressure and movement
chemoreceptors-chemicals
thermoreceptors-heat
photoreceptors-light
Name the specific sensory receptor that detects mechanical pressure
The Pacinian Corposcule
Where within the pacinian corpuscle is a sensory neurone found , what is this surrounded by
the end of the sensory neurone is in the centre of the Pacinian Corpuscle , surrounded by layers of connective tissue
each tissue layer is separated by a layer of gel
What is found within the membrane of the neurone?
What are they responsible for?
sodium ion channels
transporting sodium ions across the membrane
Name the specific type of ion channel found in the neurone ending of the Pacinian Corpuscle
What happens when these channels change shape?
stretch-mediated sodium ion channel
their permeability to sodium changes
Explain how the PC converts mechanical pressure into a nervous impulse
Give the first 3 points
1) In its normal state the stretch mediated sodium channels are too narrow to allow any sodium to diffuse in
2) When pressure is applied to the PC , the corpuscle changes shape causing the membrane around it to change shape
3)This widens the sodium ion channels and allows sodium to diffuse in
Explain how the PC converts mechanical pressure into a nervous impulse
Give the 3 final points
4) The influx of sodium ions changes the potential of the membrane-it becomes depolarised
5)This results in a generator potential
6) If the generator potential reaches threshold then it creates an action potential that passes along the sensory neurone and travels to the CNS
