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HEENOT > Eye Phys 1 > Flashcards

Eye Phys 1 Flashcards

1
Q

What are the 3 tunics/layers of the eye, and what major structures are within them?

A

fibrous layer: sclera and cornea
vascular layer (aka uvea): choroid, ciliary body, and iris
sensory layer: retina and posterior optic nerve

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2
Q

sclera

A

white of the eye; opaque, dense connective tissue

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3
Q

cornea

A

transparent, nonvascularized front covering of the eye.

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4
Q

conjunctiva

A

thin layer that covers and protects the outer portion of the eye and is continuous with the inside of the eye lid

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5
Q

lacrimal gland innervation

A

Sensory: Trigeminal (CNV)
Motor: Facial (CNVII)

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6
Q

Describe tear production and drainage

A

the lacrimal gland secretes tears (mixture of electrolytes and proteins), which flow down and in toward the lacrimal punctum, into the lacrimal sac to drain.

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7
Q

What occurs when the tear production and drainage are not in balance?

A

watery or dry eyes

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8
Q

What are the layers of tear film?

A

Mucous layer: innermost
Aqueous layer: water, electrolytes, proteins
Lipid layer: outermost layer that clings to eye and aids in lubrication

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9
Q

Iris

A

colored circle surrounding the pupil. contains aperture to adjust the size of the pupil.

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10
Q

describe the difference in the circular and radial muscles in how the iris adjusts

A

circular muscles: constrict pupil (parasympathetics)

radial muscles: dilate (sympathetics)

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11
Q

ciliary body

A

contains the ciliary muscle which controls the lens. the epithelium of the ciliary body produces the aqueous humor

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12
Q

choroid

A

vascularized portion interior to sclera; absorbs light to get a concentrated light to the retina; contains a lot of melanin so those with reduced melanin (albinism) lack the darkness of the choroid leading to a difficulty of vision.

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13
Q

lens

A

biconvex, crystalline structure that sits freely in a pocket, which is held in place by the suspensory ligaments. receives nutrients from aqueous humor.

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14
Q

Describe the refraction and accommodation abilities of the lens

A

refraction: ability to bend light waves that come through it
accommodation: ability to change shape for better focus

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15
Q

How do the ciliary muscles, suspensory ligaments and lens all work together during accommodation?

A

in a “normal” state, the ciliary muscles are relaxed, therefore the suspensory ligaments are taught and lens is flattened. When the muscles contract, the suspensory ligaments go lax and the lens rounds for accommodation.

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16
Q

Where is the anterior cavity located?

A

b/w the cornea and iris

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17
Q

What is liquid is contained w/i the anterior cavity?

A

aqueous humor

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18
Q

Aqueous humor is produced by what?

A

the ciliary body

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19
Q

Is the aqueous humor w/i the anterior cavity stagnant or flowing?

A

continuously flowing

20
Q

What condition occurs when there is an obstruction in the anterior cavity that doesn’t allow for drainage?

A

increase in pressure -> glaucoma

21
Q

posterior chamber aka vitreous chamber is located where?

A

b/w the lens and retina

22
Q

What fluid is located w/i the vitreous chamber?

A

vitreous humor - stagnant. gel like and transparent. we are born w/ it.

23
Q

vitreous humor is produced by what?

A

ciliary body

24
Q

What is the function of the vitreous humor?

A

it presses the retina to the choroid and provides shape/protection

25
Q

What condition can occur as vitreous humor ages and aggregates?

A

floaters

26
Q

If vitreous humor gets behind the retina what can happen?

A

retinal detachment

27
Q

What are the two layers of the retina?

A

outer layer: (against choroid) retinal pigment epithelium

inner layer: neural layer

28
Q

makeup of the outer layer of the retina

A

simple, cuboidal epithelium; heavily pigmented

29
Q

What is located on the inner layer of the retina?

A

rods; cones; macula; fovea

30
Q

What is the overall function of the retina?

A

photoreception

31
Q

optic disk

A

region of the retina where the optic nerve and blood vessels pass through to connect to the back of the eye. (anatomical blind spot)

32
Q

fundus

A

interior surface of eye (retina) that can be visualized w/ ophthalmoscope. should include optic disk, macula and fovea.

33
Q

What are the components of the retina involved in the visual pathway?

A

photoreceptors (rods and cones), bipolar cells, ganglion cells, optic nerve and lateral cells (horizontal and amacrine)

34
Q

Briefly describe the visual pathway

A

light hits photoreceptors which hyperpolarize causing the bipolar cells to depolarize. this activates the ganglion cells which are part of CNII that sends nerve impulses to the brain

35
Q

What is the role of lateral cells in the visual pathway

A

lateralization of information

36
Q

Describe the location of the lateral cells in relation to the bipolar cells

A

horizontal cells: pre bipolar cell

amarine cells: post bipolar cell

37
Q

refraction

A

the bending of light rays; this mechanism allows the focus of an accurate image on the retina

38
Q

emmetropic eye

A

“normal” state of the eye when the ciliary muscle is relaxed and focused on an object

39
Q

in accommodation, when the ciliary muscle is relaxed and lens is flat, what is the refraction?

A

refraction is weak - distant vision

40
Q

in accommodation, when the ciliary muscle is constricted and lens is round, what is the refraction?

A

refraction is strong - near vision

41
Q

What are the refractive deficits?

A

myopia
hyperopia
astigmatism
presbyopia

42
Q

Myopia

A

nearsighteness; the eye has a long shape with the focal point in front of the retina

43
Q

What type of lens is needed to correct myopia?

A

biconcave

44
Q

hyperopia

A

farsightedness; the eye has a short shape with the focal point behind the retina

45
Q

What type of lens is needed to correct hyperopia?

A

convex

46
Q

astigmatism

A

irregular cornea (more egg shaped) so the focus is scattered creating multiple focal points. harder to correct.

47
Q

presbyopia

A

loss of accommodation that comes w/ aging. functions like hyperopia with the focal point behind the retina.

HEENOT (13 decks)

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