Vision 2

Question 1

visual pigments are found in ______ of the photoreceptors which are derivites of _________.

Answer 1

Visual pigments are found in membran disc of the photoreceptors which are derivites of rhodopsin.

Question 2

Rhodopsin consists of an enzyme called _____ bound to the pigment _____.

Answer 2

rhodopsin consists of an enzyme called optin bound to the pigment retinal.

Question 3

retinal is _____ in both rodes and cones.

Opsin is ____ in each rod and cone.

Answer 3

retinal is IDENTICAL in both rodes and cones.

Opsin is DIFFERENT in each rod and cone.

Question 4

Bipolar cells

Answer 4

process input from photoreceptors and horizontal cells and relay impulses to ganglion cells

Question 4

horizontal cells

Answer 4

regulate info between photoreceptors and ganglion cells to adjust sensitivity of retina

Question 5

Ganglion cells

Answer 5

relay impulses from bipolar cells to the optic disc

Question 6

optic disk

Answer 6

-axons from 1 million ganglion cells
-transmit impulses to optic nerve and then to the thalamus
-the optic disk has NO PHOTORECEPTORS and is known as the blind spot

Question 7

list out the steps of vision

Answer 7

1) light is focused on the lenses through retina
2)a photon (light) strikes a rhodopsin molecule in membrane disc.
3)the rhodopsin molecule absorbs the photon and shape change in retinal component activates OPSIN
4. Rhodopsin breaks down into retinal and opsin, causing a cascade of chemical reactions which amplifys signal
5.signal chnages membrane potential of rods and cones which generates an AP from photoreceptor to optic nerve
6.AP travels along optic nerve to optic chaism and then down optic tract
7.visual APs are sent to thalamus and then to visual cortex

*Some visual APs get sent to the midbrain (refexive action) while others get sent to the pineal gland (sleep regulation)

Question 8

Near sighted

Answer 8

light is focused in FRONT of retina

Question 9

Far sighted

Answer 9

light is focused BEHIND retina