5.1.3a sensory receptors

Question 1

what is the role of a sensory receptor

Answer 1

detect stimuli and convert energy into a nervous impulse

Question 2

how do sensory receptors act as transducers?

Answer 2

they convert stimulus energy into electrical energy in the form of nervous impulses

Question 3

state the 4 types of receptors

Answer 3

• mechanoreceptor
• photoreceptor
• chemoreceptor
• thermoreceptor

Question 4

what is the stimulus and receptor for a mechanoreceptor

Answer 4

pressure
Pacinian corpuscle

Question 5

what is the stimulus and receptor for a chemoreceptor

Answer 5

chemical
olfactory receptor -detect smells
e.g. nose

Question 6

what is the stimulus and receptor for a photoreceptor

Answer 6

light
cone cell

Question 7

what is the stimulus and receptor for a thermoreceptor

Answer 7

heat
Krause bulbs
e.g. tongue

Question 8

state the transformation that takes place in a cone cell

Answer 8

light energy is converted into a nervous impulse

Question 9

where are Pacinian corpuscles found

Answer 9

• skin (fingertips)
• joints to detect when they change direction

Question 10

what do Pacinian corpuscles do

Answer 10

detect mechanical pressure and in response produce a nervous impulse
convert mechanical energy into electrical energy

Question 11

how do Pacinian corpuscles convert mechanical pressure into nervous impulse

Answer 11

pressure causes shape of Pacinian corpuscles to change and the membrane of the neurone stretches
causes stretch-mediated sodium channels to widen
sodium ions can diffuse through the channel into the membrane
influx of positive sodium ions, membrane becomes depolarised
results in a generator potential
generator potential creates an action potential
action potential passes along neurones to CNS