Light

What is the process of light energy being converted to a graded receptor potential

Phototranduction

What is the visual pigment of rods

rhodopsin (visual purple)

What is pigment synthesis

Vitamin A is oxidized and combines with ospin to form rhodopsin

What is pigment bleaching

The breakdown of rhodopsin to retinal and ospin

What is opsin

A light-sensitive protein

What causes pigment regeneration

Rhodopsin is regenerated when 11-cis-retinal is joined with opsin

What is the light transduction reaction

1) retinal absorbs light and changes shape

2) Visual pigments activates transducin (G protein)

3) Transducin activates phophodieserase

4) PDE converts cGMP to GMP, causing a decrease in cGMP

5) cGMP gated channel close, resulting in hyperpolarizaiton

What is light adaptation

Adjustment of eye to high levels of light. The rods and cones are strongly stimulated

What is dark adaptation

This is the process of gradually adjusting to the dark. It is caused by the regeneration of rods and cones, enough photo pigments must be regenerated by the cells to detect low level of light

What does bright light do to the rods

Hyperpolarizes = turns them off. hard to see; it bleaches them

What is the visual pathway

retina -> optic nerve -> optic chiasm -> optic tracts -> lateral geniculate nucleus (LGN) of thalamus -> visual radiations -> visual cortex

Where does the medial retina receive light from

The lateral most aspects of the visual field; the eye reverses all images

What allows for depth perception

binocular vision

Do the visual fields of the eyes overlap at all

Yes, considerably. Both eyes work together

What does loos of an eye of damage to one optic nerve do

Loss of 3-D vision and peripheral vision to the damaged side

What does a stroke on the left visual cortex cause

Right half blindedness