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Flashcards in Exam 2 Deck (114)
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1

When light strikes a photoreceptor, what happens? And what happens to glutamate?

Hyperpolarizes; and decreased release of glutamate

2

The greatest refraction of light in the eye occurs at which interface?

Air-cornea

3

In a 60 year old, the lens strength can vary by how many diopters?

0

4

In a young child, the lens strength can vary by how many diopters?

14

5

What is a diopter?

It is a unit of measurement = 1 meter of focal length

6

When reading a book what is the refractive power of your lens like?

High

7

What condition is correlated with a focal point in front of the retina?

Myopia, or near sighted

8

What condition is correlated with a focal point behind the retina?

Hyperopia, or far sighted

9

What is Astigmatism and what part of the eye is more commonly effected?

irregular shape, and cornea more common then lens

10

What is Emmetropia? What are the ciliary muscles like in a patient with this?

Normal vision; relaxed in distant vision

11

What kind of lens would fix hyperopia

convex

12

What kind of lens would fix myopia

concave

13

How does light pass to the long slender cones relatively unimpeded in the fovea centralis?

Blood vessels and cells are displaced laterally

14

What is presbyopia

loss of elasticity of lens with age

15

What area of the eye has the greatest acuity?

fovea centralis

16

The central fovea area of greatest acuity is composed almost entirely of what?

Long slender cones

17

As you move from fovea centralism to periphery of retina does visual acuity decrease? And if so, how much?

Yes; more 10 fold

18

What causes the natural blind spot in your eye?

lack of receptors in the optic disc

19

What is stereopsis

binocular vision (eyes separated by 2 inches)

20

What secretes your aqueous humor?

the ciliary body

21

What is normal intraocular pressure produced by the aqueous humor?

12-20 mmHg

22

What is Glaucoma, and if left untreated what can occur?

Increased intraocular pressure; compression of optic nerve which can lead to blindness

23

True or false, the retina is not considered an extension of the peripheral CNS

false

24

What are the only retinal cells that can generate action potentials?

ganglion cells

25

What does light break down in the rods?

rhodopsin

26

What does light break down in cones?

cone pigments

27

True or false as rhodopsin is broken down in retina, photoreceptor cells hyper polarize

true

28

True or false as rhodopsin is broken down in retina, and photoreceptor cells hyper polarize more glutamate is released?

false, less glutamate is released

29

When it is dark out, how do your retina cells react? Is there more neurotransmitter released?

the cells depolarize, and yes more is released

30

When it is bright out, how do your retina cells react? Is there more neurotransmitter released?

the cells hyper polarize; and no less is released