Exam 2: Eye

Question 1

synapses

electrical impulses

Answer 1

linkedby gap junctions, allow movement

Question 2

synapses

Chemical impulses

Answer 2

• most common
• neural transmitters are released
• binds to channels cell in themembrane
• may or may not generate AP

Question 3

eye

describe the fibrous layer

innermost?vascular?contains?

Answer 3

• outermost layer
• avascular
• contains the sclera and the cornea

Question 4

eye

what is the sclera?

5/6th

Answer 4

tough outer layer,the white of the eye

Question 5

eye

What is the cornea?

Answer 5

anterior portion; transparent part of the eye

Question 6

eye

describe the vascular layer

(Uvea), innermost? vascular?contains?

Answer 6

• middle layer
• vascular
• holds the choroid, Ciliary body, and iris

Question 7

eye

what is the choroid?

Answer 7

helps nourish the inner layer of the eye

Question 8

eye

What is the ciliary body?

Answer 8

produces aqueous humor; contains the ciliary muscle

Question 9

eye

What is the ciliary muscle?

Answer 9

ciliary muscle is connected to the lens and is used to focus the light in the on the retina
via suspensory ligaments

Question 10

eye

What is the iris?

Answer 10

Pigmented donut of the muscle,the hole in the middle of the iris is the pupil regulates the amountof light entering the eye

Question 11

eye

What muscles in the iris help regulate the amount of light entering the pupil?

Answer 11

• constrictor pupillae
• dilator pupillae

Question 12

eye

what is the function of the constrictor pupillae and dialator?

Answer 12

• CP makepupil

Question 13

eye

what is the function of the constrictor pupillae and dialator?

Answer 13

• CP makes pupil smaller
• DP makes pupil larger

Question 14

what two parts make up the retina?

Answer 14

• retinal pigmented epithelium
• nerual layer

Question 15

What is the retinal pigmented epithelium?

melanin

Answer 15

• tissue that contains melanin ( a dark protien); which absorbs light to prevent light from reflecting back across retina

Question 16

What is the neural layer?

Answer 16

a layer in the eye comprised of 3 layers

Question 17

What are the 3 layers Of the neural layer?

Answer 17

• inner layer of ganglion cells
• middle layer of bipolar amacrine and horizontal cells
• outer layer of photoreceptors

Question 18

What are the 2 photoreceptors involved in phototransduction?

Answer 18

• rods
• cones

Question 19

what is photo transduction?

Answer 19

conversion of light energy into electrical energy

Question 20

what are rods?

Answer 20

photoreceptors used for preceiving black and white vision; responds to low intensity light

Question 21

what are cones?

Answer 21

photoreceptors used for perceiving colored vision; responds to high intensity light

Question 22

what is the fovea?

Answer 22

indentation in the retina
- contains only cones
- best visual acuity

Question 23

what is the optic disk?

Answer 23

blind spot found in the retina

Question 24

internal space

where is the posterior cavity located?

contains gelatinous mass

Answer 24

behind the lens; contains the vitreous humor

Question 25

internal space

where is the anterior cavity located?

Answer 25

infront of the lens; filled with aqueous humor; contains two parts
- anterior chamber
- posterior chamber

Question 26

anterior cavity

how far does the anterior chamber stretch?

C to I

Answer 26

from the cornea to the iris

Question 27

anterior cavity

how far does the posterior chamber strecth?

I to L

Answer 27

from iris to lens

Question 28

what does the aqueous humor nourish?

L and C

Answer 28

lens and cornea

Question 29

lenses

what is the function of ciliary muscle?

Answer 29

change the lenses shape in order to change the angle of refraction

Question 30

light

what is emmotropic eye?

city girls winning

Answer 30

20/20 vision

Question 31

light

what is myopia?

Answer 31

• near sightdness
• lens or cornea are too bulged

Question 32

light

what is hyperopia?

Answer 32

• far sightedness
• lens or cornea is too flat

Question 33

what is an astigmatism?

Answer 33

irregularly shaped lens or cornea causing erratic refraction

Question 34

what is presbyopia?

Answer 34

hardening of the lens w/ age

Question 35

what is a catract?

Answer 35

lens or cornea becomes opaque

Question 36

what is glucomma?

Answer 36

increase bulge of the cornea due to the excessive secretion of aqueous humor

Question 37

what is rhodopsin?

Answer 37

a photo pigment found in the outer segment of rods and cones

Question 38

what are the 4 diffrent types of rhodopsin?

Answer 38

• type 1 found in rods
• types 2-4 found in 3 diffrent types of cones

Question 39

dark phase

what happens during the dark phase?

4 steps

Answer 39

1) cGMP levels are high in the cell
2) Na+ channels are open
3) Ca+ enters and neurotransmitters are released bipolar cells

Question 40

light phase

what happens during the light phase?

4 steps

Answer 40

1) light strikes rhodopsin and splits into retinal and opsin
2) bleached opsin activates the process of transducin which actives the enzyme phosphodiestrase which increase the breakdown of cGMP
3) sodium channels close causing the cell to hyperpolarize
4) calcium channels close and transmitter release is decreased

Question 41

what is the purpose of phosphodiesterase?

Answer 41

it causes cGMP levels to break down

Question 42

what are the 3 diffrent types on cones?

S, M, L

Answer 42

• Small or blue cones which respond to wavelengths near 420nm
• medium or green cones which respond to wavelengths nesr 520 nm
• large or red cones which respond to wavelengths near 560 nm