Flashcards in Exam 2 Deck (114)
When light strikes a photoreceptor, what happens? And what happens to glutamate?
Hyperpolarizes; and decreased release of glutamate
The greatest refraction of light in the eye occurs at which interface?
In a 60 year old, the lens strength can vary by how many diopters?
In a young child, the lens strength can vary by how many diopters?
What is a diopter?
It is a unit of measurement = 1 meter of focal length
When reading a book what is the refractive power of your lens like?
What condition is correlated with a focal point in front of the retina?
Myopia, or near sighted
What condition is correlated with a focal point behind the retina?
Hyperopia, or far sighted
What is Astigmatism and what part of the eye is more commonly effected?
irregular shape, and cornea more common then lens
What is Emmetropia? What are the ciliary muscles like in a patient with this?
Normal vision; relaxed in distant vision
What kind of lens would fix hyperopia
What kind of lens would fix myopia
How does light pass to the long slender cones relatively unimpeded in the fovea centralis?
Blood vessels and cells are displaced laterally
What is presbyopia
loss of elasticity of lens with age
What area of the eye has the greatest acuity?
The central fovea area of greatest acuity is composed almost entirely of what?
Long slender cones
As you move from fovea centralism to periphery of retina does visual acuity decrease? And if so, how much?
Yes; more 10 fold
What causes the natural blind spot in your eye?
lack of receptors in the optic disc
What is stereopsis
binocular vision (eyes separated by 2 inches)
What secretes your aqueous humor?
the ciliary body
What is normal intraocular pressure produced by the aqueous humor?
What is Glaucoma, and if left untreated what can occur?
Increased intraocular pressure; compression of optic nerve which can lead to blindness
True or false, the retina is not considered an extension of the peripheral CNS
What are the only retinal cells that can generate action potentials?
What does light break down in the rods?
What does light break down in cones?
True or false as rhodopsin is broken down in retina, photoreceptor cells hyper polarize
True or false as rhodopsin is broken down in retina, and photoreceptor cells hyper polarize more glutamate is released?
false, less glutamate is released
When it is dark out, how do your retina cells react? Is there more neurotransmitter released?
the cells depolarize, and yes more is released