Vision Flashcards
What makes up the outer layers of the eye
The Scalera choroid and retina
What is the Scalera and when does it become at the front of the eye
It’s the outer most layer, in front it becomes clear and see through
Where is the coroid and was it become
It is packed with blood vessels and becomes the ciliary body which becomes the iris and controls the pupil
What is the job of the lens in the cornea
To bed light onto the retina
What is the canal of schlemm
Produces aqueous humor, if it doesn’t drain glaucoma it becomes president which is the buildup of pressure that pushes on the nerves leading to blindness
The optic disc is also the
Blindspot
To see close up the lens is? To see far away the lenses?
Round, flat
Accommodation
The process by which the eye Adjust the shape of the lens to keep objects and focus on the retina
What is hyperopia
The focal point falls behind the retina, farsightedness, close-up is blurry
What is myopia
The focal point falls in front of the retina, nearsightedness, distance is fuzzy
Well the rods and cones for
Cones are for colour vision and rods are for mono chromatic vision
What sells axons converge to form the optic nerve
Ganglion cells
What are amacrine cells
Support south, drown out other cells for clear information, will release GABA so it’s a clear message
True or false? Columns have low sensitivity, high acuity for clear details, and have a little convergence in the retinal pathways
True
What is rhodopsin made of
The protein opsin and a reversibly bound cofactor retinal
Retinal absorbs… And changes…Converting…
It absorbs light and changes configuration Converting light energy into a change in membrane potential
Explain pigment synthesis
Rhodopsin forms and accumulates in the dark. Vitamin A is oxidized to form 11-cis-retinal Which combines with opsin
Explain pigment bleaching
When rhodopsin absorbs light, retinol changes to all trans retinol and ops and becomes activated and separates from retinol
Explain pigment regeneration
11 cis retinal is re-generated and re-joins opsin
Photo transduction in the dark
Rhodopsin is an active, cGMP is high, and K channels are open so the cell is depolarizing and there is a release of neurotransmitters onto you bipolar neurons that cause an inhibitory postsynaptic potential. Because the bipolar cells hyperpolarized the calcium channels clothes inhibiting neurotransmitter released onto the ganglion cell. So no action potentials occur along the optic nerve
Photo transduction in the light
Light bleached rhodopsin
Opsin decreases cGMP
Sodium and potassium channels clothes in the cell becomes hyperpolarized. Neurotransmitter released decreases in proportion to the amount of light. Because there is a lack of inhibitory postsynaptic potential’s in the bipolar sell it can be polarized and release an excitatory postsynaptic potential onto the ganglion cell
Fibres from the middle aspect of each I can cross at the optic chiasm and continue via the optic tract. True or false?
True
The right optic tract carries representation of the
Left half of the visual field
