Sensory receptors- Pacinian corpuscle

Question 1

what are examples of sense organs and what is their role

Answer 1

skin, nose, eye, ear, tongue

role of transducers of converting one form of energy to another form of energy (electrical)

Question 2

explain skin as a sensory receptor

Answer 2

-mechanoreceptors or pressure receptors (pacinian corpuscle and thermoreceptors for temp and nociceptors for pain

-detect energy change of pressure

Question 3

how do sensory receptors carry out transduction

Answer 3

-respond to changes in the environment (stimuli) by converting stimulus energy (e.g light, sound, heat) into a generator potential also called receptor potential

Question 4

what is the magnitude of the generator potential (depolarisation) proportional to

Answer 4

proportional to magnitude of the stimulus, once reaches the threshold level, an action potential is generated transmitted along axon of sensory neuron

small stimulus= one or two gated sodium ion channels in membrane open= small potential difference across membrane change= generator potential

large stimulus= more gated sodium ion channels in membrane open=large change in potential difference=action potential

Question 5

what is the pacinian corpuscle and where is it found

Answer 5

a transducer that converts pressure/ mechanical energy into energy of nervous impulse

found most in fingers, soles of feet and external genitalia

Question 6

what are the features of pacinian corpuscle

Answer 6

-capsule made of layers of connective tissue separated by a viscous gel
-fibroblast= producing the connective tissue
-axon of sensory nuerone surrounded by a myelin sheath
-single nerve fibre
-nuerone membrane and stretch mediated sodium channels

Question 7

explain how the pacinian corpuscle works

Answer 7

1.at rest the stretch-mediated Na+ channels are too narrow to allow Na+ to pass through them (membrane at resting potential)
2.apply pressure, capsule is deformed and receptor membrane is stretched
3.stretching of receptor membrane widens the Na+ channels= Na+ influx
4.receptor membrane is depolarised, Na+ influx causes a change in the potential difference of the membrane
5.generator potentials can create an action potential that passes to the sensory neuron and on to the CNS (sensory cortex of the brain)