Photoreception
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function of the eye
to focus light onto photoreceptors found at the retina in the back of the eye
Sclera -what is it function (2)
-thick white outer layer -protection and shape
Cornea -what is it -what does the tissue need and how does it get it
window to the eye, front of sclera tissue needs dissolved o2 which it gets from the aqueous humour
choroid -what is it -what does it contain and why
underneath the sclera contains blood vessles to supply the choroid with oxygen and nutrients and pigmented granules to create a black interior and prevent light from bouncing inside the eye
iris -what does it contain and its function
thin muscles to constrict/dialate pupil
pupil, opening of the eye -why is it black -what determines its size and what is it called -what influences constriction and dilation
-because of dark choroid layer -the iris, light adaptation and pupillary reflex -the symaphtetic and parasympathetic nervous systems
lens -what shape is it and where is it located -what does it do
-bioconvex, behind the iris -it refracts light and produces an inverted iamge on the retina
Retina- what is it -what 3 layers -what do rods and cones do -what is the blind spot
innermost layer of the eye, tissue -ganglion, bipolar, photoreceptors -rods and cones convert light energy into nerve impulses and seend it to the optic nerve and brain -the blind spot is where optic nerve exists and there are no photorecepotrs here, so no images can be produced
Rods -what intesity light -how many rods connect to a bipolar cell/nerve and what does that mean -what pigment do rods contain and what is it made up of -what happens to the pigment if its dark, dim, or bright
-low -multiple connects, meaning not very detailed -rhodopsin which contains vitamin A (protein opsin and retinal) -if its too dark, rhodopsin stimulates relwase of hibhibotry neurons which prevent impulses, if its dim, rhodopsin splits and stops the release of them, if too bright, it breaks down too quickly
Cones -what intensity light -3 types of cones -how many rods connect to a bipolar/nerve -where are cones concentrated
-high -rgb -one, better detail -fovea centralis which is righ t behind the pupil and most light rays fall here
What does binocular vision mean and why do we have it
it means that our left and right sides of the brain recieve information from the opposite eye, and this makes processing quicker