Eye Phys 1

Question 1

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

Answer 1

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

Question 2

sclera

Answer 2

white of the eye; opaque, dense connective tissue

Question 3

cornea

Answer 3

transparent, nonvascularized front covering of the eye.

Question 4

conjunctiva

Answer 4

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

Question 5

lacrimal gland innervation

Answer 5

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

Question 6

Describe tear production and drainage

Answer 6

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.

Question 7

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

Answer 7

watery or dry eyes

Question 8

What are the layers of tear film?

Answer 8

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

Question 9

Iris

Answer 9

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

Question 10

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

Answer 10

circular muscles: constrict pupil (parasympathetics)

radial muscles: dilate (sympathetics)

Question 11

ciliary body

Answer 11

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

Question 12

choroid

Answer 12

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.

Question 13

lens

Answer 13

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

Question 14

Describe the refraction and accommodation abilities of the lens

Answer 14

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

Question 15

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

Answer 15

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.

Question 16

Where is the anterior cavity located?

Answer 16

b/w the cornea and iris

Question 17

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

Answer 17

aqueous humor

Question 18

Aqueous humor is produced by what?

Answer 18

the ciliary body

Question 19

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

Answer 19

continuously flowing

Question 20

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

Answer 20

increase in pressure -> glaucoma

Question 21

posterior chamber aka vitreous chamber is located where?

Answer 21

b/w the lens and retina

Question 22

What fluid is located w/i the vitreous chamber?

Answer 22

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

Question 23

vitreous humor is produced by what?

Answer 23

ciliary body

Question 24

What is the function of the vitreous humor?

Answer 24

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

Question 25

What condition can occur as vitreous humor ages and aggregates?

Answer 25

floaters

Question 26

If vitreous humor gets behind the retina what can happen?

Answer 26

retinal detachment

Question 27

What are the two layers of the retina?

Answer 27

outer layer: (against choroid) retinal pigment epithelium | inner layer: neural layer

Question 28

makeup of the outer layer of the retina

Answer 28

simple, cuboidal epithelium; heavily pigmented

Question 29

What is located on the inner layer of the retina?

Answer 29

rods; cones; macula; fovea

Question 30

What is the overall function of the retina?

Answer 30

photoreception

Question 31

optic disk

Answer 31

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

Question 32

fundus

Answer 32

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

Question 33

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

Answer 33

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

Question 34

Briefly describe the visual pathway

Answer 34

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

Question 35

What is the role of lateral cells in the visual pathway

Answer 35

lateralization of information

Question 36

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

Answer 36

horizontal cells: pre bipolar cell | amarine cells: post bipolar cell

Question 37

refraction

Answer 37

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

Question 38

emmetropic eye

Answer 38

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

Question 39

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

Answer 39

refraction is weak - distant vision

Question 40

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

Answer 40

refraction is strong - near vision

Question 41

What are the refractive deficits?

Answer 41

myopia hyperopia astigmatism presbyopia

Question 42

Myopia

Answer 42

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

Question 43

What type of lens is needed to correct myopia?

Answer 43

biconcave

Question 44

hyperopia

Answer 44

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

Question 45

What type of lens is needed to correct hyperopia?

Answer 45

convex

Question 46

astigmatism

Answer 46

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

Question 47

presbyopia

Answer 47

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