receptors

Question 1

pacinian corpuscle

Answer 1

-generqaqting a generator potential
-mechanical stimulus deforms lamellae and stretch mediated sodium ion channel
-sodium ions channels open and sodiumm ions diffuse into sensory nuerones
greater pressure causes more channels to open and more sodium ions to enter
causes depolarisation generating a genrator potential
if generator potential reaches a threshold an action potential is triggered
what does it illustrate-
receptors only respond toi specific stimuli
all or nothing principle

Question 2

rod cells

Answer 2

more at periphery in retinal, absent at fovea
one type of rod containing one pigment
rods connected in groups to one bipolar cell
very senstive to light-spatial summation-more likely to meet threshold
low visual acuity-in groups to one bipolar-can only generate one AP so cant distinguish between seperate light sources
black and white-one type of pigment

Question 3

cone cells

Answer 3

concentrated at fovea, fewer at periphery
3 types of cones containing different optical pigents
one cone joins one nuerone
l;ess sensitive to light-no spatial summation
high visual acuity-each cell has its own nuerone so it recieved seperate impulses
colour-3 types of cones which have optical pigemnts whihc absorb different wavelengths