Quiz 9 - Eye Flashcards Preview

Anatomy > Quiz 9 - Eye > Flashcards

Flashcards in Quiz 9 - Eye Deck (38):
1

the eye

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

2

accessory structures to the eye

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

3

eyelid

protects eyes: "windshield wipers" keeps eyes moist by blinkin

4

eye lashes

moving hair causes blinking reflex

5

orbital fat

provides padding and insulation

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lacrimal glands

produce lacrimal fluid (tears)
- contains antibodies and lysozyme (kills bacteria)
- protects, moistens and lubricates eye

7

conjunctiva

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

8

three layers of tunics

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

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parts of fibrous tunic

sclera and cornea

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scelra

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

11

cornea

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

12

parts of vascular tunic

choroid
iris
pupil
ciliary body
ciliary muscle
suspensory ligaments

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choroid

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

14

iris

contains pigment cells and smooth muscle cells, regulates amount of light entering eye
- pupillary sphincter muscles
- pupillary dilator muscles

15

pupillary sphincter muscles

form concentric circle, contraction decreases pupil

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pupillary dilator muscles

extend radially, contraction enlarges pupil

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pupil

central opening of iris

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pupillary reflexes

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

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ciliary body

composed mostly of ciliary muscle

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ciliary muscle

right of smooth muscle that controls lens shape

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suspensory ligaments of lens

hold lens in place

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lens

focus the visual image on the retina

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for long distance...

ciliary muscles relax
- places tension on ligament
- pulls lens taut
- lens becomes more flat

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for closer distance...

ciliary muscles contract
- reducing tension on ligament
- lens becomes more convex

25

parts of neural tunic

retina
photoreceptors
fovea
optic disc

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retina

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

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photoreceptors

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)

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fovea

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

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visual acuity and parts

sharpness of vision
- myopia
- hyperopia
- astigmatism

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myopia

(nearsightedness) image is focused in front of retina

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hyperopia

(farsightedness) image is focused behind retina

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astigmatism

condition that causes blurred vision

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optic disc

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

34

chambers of the eye

eyeball is hollow and interior is divided into 2 cavaties

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anterior cavity

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

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aqueous humor

- plasma-like fluid secreted by ciliary body
- supports, nourishes and removes wastes from lens and cornea

37

posterior cavity (vitreous chamber)

vitreous chamber filled with vitreous humor

38

vitreous humor

clear, gel-like fluid that:
- transmits light
- supports lens and holds retina against eye wall
- contributes to intraocular pressure