Quiz 9 - Eye

Question 1

the eye

Answer 1

visual receptors enable us to detect light and to receive detailed visual images

Question 2

accessory structures to the eye

Answer 2

eyelid, eye lashes, orbital fat, lacrimal glands, conjunctiva

Question 3

eyelid

Answer 3

protects eyes: “windshield wipers” keeps eyes moist by blinkin

Question 4

eye lashes

Answer 4

moving hair causes blinking reflex

Question 5

orbital fat

Answer 5

provides padding and insulation

Question 6

lacrimal glands

Answer 6

produce lacrimal fluid (tears)

• contains antibodies and lysozyme (kills bacteria)
• protects, moistens and lubricates eye

Question 7

conjunctiva

Answer 7

epithelium coving inner surface of eyelids and outer surface of the eye

Question 8

three layers of tunics

Answer 8

fibrous tunic (outer)
vascular tunic (middle)
neural tunic (inner)

Question 9

parts of fibrous tunic

Answer 9

sclera and cornea

Question 10

scelra

Answer 10

“white” of eye - outer protective covering and dense, fibrous connective tissue

Question 11

cornea

Answer 11

“window” of eye - continuous with the sclera, transparent, most sensitive part of the eye

Question 12

parts of vascular tunic

Answer 12

choroid
iris
pupil
ciliary body
ciliary muscle
suspensory ligaments

Question 13

choroid

Answer 13

middle dark layer that contains blood vessels, delivers oxygen and nutrients to other layers

Question 14

iris

Answer 14

contains pigment cells and smooth muscle cells, regulates amount of light entering eye

• pupillary sphincter muscles
• pupillary dilator muscles

Question 15

pupillary sphincter muscles

Answer 15

form concentric circle, contraction decreases pupil

Question 16

pupillary dilator muscles

Answer 16

extend radially, contraction enlarges pupil

Question 17

pupil

Answer 17

central opening of iris

Question 18

pupillary reflexes

Answer 18

close vision and bright light - constrict
distant vision and dim light - dilate
emotional state - dilate
SNS - dilate
PNS - constrict

Question 19

ciliary body

Answer 19

composed mostly of ciliary muscle

Question 20

ciliary muscle

Answer 20

right of smooth muscle that controls lens shape

Question 21

suspensory ligaments of lens

Answer 21

hold lens in place

Question 22

lens

Answer 22

focus the visual image on the retina

Question 23

for long distance…

Answer 23

ciliary muscles relax

• places tension on ligament
• pulls lens taut
• lens becomes more flat

Question 24

for closer distance…

Answer 24

ciliary muscles contract

• reducing tension on ligament
• lens becomes more convex

Question 25

parts of neural tunic

Answer 25

retina
photoreceptors
fovea
optic disc

Question 26

retina

Answer 26

neural lauyer contains photoreceptors: dark, pigmented layer prevents light scattering

Question 27

photoreceptors

Answer 27

rods - light sensitive; important in seeing in dim light and peripheral vision (~125 million rods)
cones - important for color vision (~6 million cones) - color blind individuals lacking in # of cones)

Question 28

fovea

Answer 28

• pine-sized pit containing highest concentration of cones
• site of sharpest vision
• by-passes neural layers to light strikes cones directly

Question 29

visual acuity and parts

Answer 29

sharpness of vision

• myopia
• hyperopia
• astigmatism

Question 30

myopia

Answer 30

(nearsightedness) image is focused in front of retina

Question 31

hyperopia

Answer 31

(farsightedness) image is focused behind retina

Question 32

astigmatism

Answer 32

condition that causes blurred vision

Question 33

optic disc

Answer 33

(blind spot) - where axons of retinal neurons gather and exit eye in optic nerve; light focused here will not be seen

Question 34

chambers of the eye

Answer 34

eyeball is hollow and interior is divided into 2 cavaties

Question 35

anterior cavity

Answer 35

anterior chamber - filled with aqueous humor
posterior chamber (vitreous chamber) - large; contains the gelatinous vitreous humor

Question 36

aqueous humor

Answer 36

• plasma-like fluid secreted by ciliary body

- supports, nourishes and removes wastes from lens and cornea

Question 37

posterior cavity (vitreous chamber)

Answer 37

vitreous chamber filled with vitreous humor

Question 38

vitreous humor

Answer 38

clear, gel-like fluid that:

• transmits light
• supports lens and holds retina against eye wall
• contributes to intraocular pressure