Afferent Divison of the PNS

Question 1

Red wavelengths are how many nm?

Answer 1

750

Question 2

Blue wavelengths are how many nm?

Answer 2

450

Question 3

Retina

Answer 3

sensory neruon with photoreceptors

Question 4

When do rods respond

Answer 4

dim light

Question 5

Where are rods located

Answer 5

in the periphery of the retina

Question 6

Do rods have low or high acuity

Answer 6

low

Question 7

Do rods have color vision

Answer 7

no

Question 8

When do cones respond

Answer 8

respond in bright light

Question 9

Where are cones located

Answer 9

dense around fovea centrails

Question 10

Do cones have low or high acuity

Answer 10

high

Question 11

What colors are in color vision and their nm

Answer 11

red: 558
Blue: 420
Green: 531`

Question 12

Where does phototransduction occur?

Answer 12

in the back of the retina

Question 13

Steps in the outer segment of the cone? (Dark)

Answer 13

-Guanylyl cyclase coverts GMP to cGMP
-cGMP open up cation channel which allows sodiuma nd calcium to come in
-which causes the out segment of the cone to become depolarized in the dark

Question 14

Steps in the outer segment of the cone (light)

Answer 14

-Photon of light is recieved by retinal which sits inside of a photopigment called opsin
-The photon alters the shape of the retinal
-Interaction of light with the retinal activates the G protein called transducin
-The activates an enzyme called cGMP-phosphodiesterase which converts cGMP to GMP which closes the cation channel

Question 15

The “on-pathway “ the dark

Answer 15

-cGMP is high and the photoreceptor depolarizes
-when depolarized it released and imhibitory NT onto a bipolar cell
-the bipolar cell is hyperpolaried so no excitaory NT is rleased into the ganglion cell
-No Aps to visual cortex in the occipital lobe

Question 16

The “on-pathway” the light

Answer 16

cGMP levles fall and the photoreceptor repolarizes because cation channels close
-because it repolarizes no inhibitory NT is released onto the bipoalr cell
-the bipolar cell spontaneously depolarizes and an exictatory NT is released onto ganglion cell
-APs go down the visiual cortex into the occipital lobe

Question 17

Why does the optic disc cause a blind spot

Answer 17

it lacks photoreceptors so photons striking this region cannot produce an image