Chapter 15 Eye Anatomy

Question 1

Protect and aid in function of eye
Include: eyebrows, eyelids, conjunctiva, lacrimal apparatus, extrinsic eye muscles

Answer 1

Accessory structures

Question 2

70% of body’s sensory receptors located here
Half of cerebral cortex is involved in visual processing
Small sphere; only 1/6th is seen
Features: accessory structures, eyeball

Answer 2

Eye

Question 3

Overlie supraorbital margins
Function: shade eye from sunlight, prevent perspiration from reaching eye

Answer 3

Eyebrows

Question 4

A.k.a. palpebrae
Thin, skin covered folds that protect eye anteriorly
Separated at palpebral fissure
Meet in corners at medial and lateral commissures

Answer 4

Eyelids

Question 5

Project from eyelids
Follicles of eyelash hairs are innervated
When eyelashes touched it triggers reflex blinking

Answer 5

Eyelashes

Question 6

Located at medial commissure; contains oil and sweat glands

Answer 6

Lacrimal caruncle

Question 7

Part of eyelid; Supporting connective tissue that give eyelids shape; has “plates” that anchor orbicularis oculi and levator palpebrae superioris muscles

Answer 7

Tarsal plates

Question 8

Modified sebaceous glands that produce oily secretion that lubricates lid and eye

Answer 8

Tarsal glands

Question 9

Infected tarsal gland, creates a cyst called _______

Answer 9

Chalazion

Question 10

Inflammation of any of the smaller sebaceous gland

Answer 10

Stye

Question 11

Transparent mucous membrane that produces a lubricating mucus secretion
3 parts: Palpebral, bulbar, conjunctival sac

Answer 11

Conjunctiva

Question 12

Membrane that lines underside of eyelids

Answer 12

Palpebral conjunctiva

Question 13

Membrane that covers white of eyes; small blood vessels found here

Answer 13

Bulbar conjunctiva

Question 14

Space between palpebral and bulbar conjunctiva; where contact lens sit

Answer 14

Conjunctival sac

Question 15

Inflammation of the conjunctiva resulting in reddened, irritated eyes

Answer 15

Conjunctivitis

Question 16

Turns eye pink
Conjunctival infection caused by bacteria or viruses

Answer 16

Pink eye

Question 17

Located in orbit above lateral end of eye; Secretes lacrimal secretions (tears)

Answer 17

Lacrimal gland

Question 18

Where tears drain into; ______ then ________

Answer 18

Lacrimal sac
Nasolacrimal duct

Question 19

6 straplike muscles that originate in the bony orbit and insert into eyeball
Enable eye to follow moving objects, maintain shape, and hold it in orbit

Answer 19

Extrinsic eye muscles
1. Lateral rectus
2. Medial rectus
3. Superior rectus
4. Inferior rectus
5. Inferior oblique
6. Superior oblique

Question 20

Moves eye laterally

Answer 20

Lateral rectus

Question 21

Moves eye medially

Answer 21

Medial rectus

Question 22

Elevates eye and turns it medially

Answer 22

Superior rectus

Question 23

Depresses eye and turns it medially

Answer 23

Inferior rectus

Question 24

Elevates eye and turns it laterally
Originates from medial surface and inserts on inferolateral part of eye

Answer 24

Inferior oblique

Question 25

Depresses eye and turns it laterally Originates at common tendinous ring then passes through fibrocartilage loop (trochlea) and inserts in superolateral part of eye

Answer 25

Superior oblique

Question 26

Occurs when movements of external muscles of two eyes are not perfectly coordinated Ex. Seeing two images instead of one

Answer 26

Diplopia

Question 27

Cross eyed Congenital weakness of external eye muscles

Answer 27

Strabismus

Question 28

Internal cavity of eyeball filled with fluids called ____

Answer 28

Humors

Question 29

3 layers of eyeball:

Answer 29

1. Fibrous layer 2. Vascular layer 3. Inner layer

Question 30

Largest segment of eye behind lens

Answer 30

Posterior segment

Question 31

Smaller segment of eye in front of lens

Answer 31

Anterior segment

Question 32

Outermost layer of eyeball; Dense avascular connective tissue Two regions: sclera, cornea

Answer 32

Fibrous layer

Question 33

Opaque posterior region of fibrous layer White region of eye Protects and shapes eyeball, anchors extrinsic muscles

Answer 33

Sclera

Question 34

Transparent anterior fibrous layer Forms clear window that lets light enter eye and bends light; No blood vessels with numerous pain receptors

Answer 34

Cornea

Question 35

Middle pigmented layer of eye A.k.a. uvea Three regions: choroid, cilliary body, iris

Answer 35

Vascular layer

Question 36

Posterior portion of vascular layer in eyeball wall Supplies blood to all layers of eyeball Brown pigment absorbs light to prevent scattering of light, which would cause visual confusion

Answer 36

Choroid region

Question 37

Anteriorly, choroid becomes this region Thickened ring of tissue surrounding lens; Controls the shape of the lens

Answer 37

Ciliary body

Question 38

Extends from ciliary processes to lens and holds lens in position

Answer 38

Ciliary zonule

Question 39

Biconvex, transparent, flexible, and avascular; Changes shape to precisely focus light on retina Lens epithelium: anterior region of cuboidal cells that differentiate into lens fiber cells Lens fibers: form bulk of lens and are filled with transparent protein crystallin

Answer 39

Lens

Question 40

Transparent protein that makes up lens

Answer 40

Crystallin

Question 41

Lens becomes _________ with age

Answer 41

Denser

Question 42

Clouding of lens Consequence of aging, diabetes mellitus, heavy smoking, frequent exposure to intense sunlight Clumped crystallin

Answer 42

Cataract

Question 43

Colored part of eye between cornea and lens, continuous with ciliary body

Answer 43

Iris

Question 44

Central opening of iris that regulates amount of light entering eye

Answer 44

Pupil

Question 45

Pupils constrict; diameter decreases Muscles in pupil that constrict from bright light and close vision

Answer 45

Sphincter pupillae

Question 46

Pupils dilate; diameter increases Muscles in pupil that constrict due to distant vision and dim light

Answer 46

Dilator pupillae

Question 47

Pupils ______ when subject matter is appealing or requires problem solving skills

Answer 47

Dilate

Question 48

Inner layer of eyeball Originates as an outpocketing of brain Contains photoreceptor cells, neurons, glial cells 2 layered membrane: pigmented layer, neural layer

Answer 48

Retina

Question 49

Transparent layer of retina that runs anteriorly to margin of ciliary body Has serrated edges called ora serrata 3 main neurons: Photoreceptors, bipolar cells, ganglion cells

Answer 49

Neural layer (retina)

Question 50

Serrated junction between the retina and ciliary body

Answer 50

Ora serrata

Question 51

Single-cell thick lining next to choroid Extends anteriorly, covering ciliary body and iris Functions: absorbs light and prevents it from scattering Stores vitamin A

Answer 51

Pigmented layer (retina)

Question 52

Ganglion cell axons exit eye as ______

Answer 52

Optic nerve

Question 53

Photoreceptors --> bipoloar cells --> ganglion cells

Answer 53

Movement of signals

Question 54

Dim light, peripheral vision receptors; More numerous and more sensitive No color vision Lots in periphery

Answer 54

Rods

Question 55

Vision receptors for bright light High resolution color vision

Answer 55

Cones

Question 56

Choroid supplies to outer third (photoreceptors) Central artery and vein supply to inner two thirds

Answer 56

Sources of blood supply

Question 57

Site where optic nerve leaves eye Lacks photoreceptors, A.k.a. Blind spot

Answer 57

Optic disc

Question 58

Area at posterior; lateral to blind spot; next to fovea centralis Contains mostly cones

Answer 58

Macula lutea

Question 59

Tiny pit in center of macula lutea that contains all cones, so is region with best visual acuity

Answer 59

Fovea centralis

Question 60

Fluid in posterior segment that holds retina in place Transmits light, supports posterior surface of lens Holds neural layer of retina firmly against pigmented layer

Answer 60

Vitreous humor

Question 61

Pigmented and neural layers separate, allowing jelly-like vitreous humor to seep between them Can lead to permanent blindness

Answer 61

Retinal detachment

Question 62

Segment posterior to lens Contains vitreous humor

Answer 62

Posterior segment

Question 63

Anterior to lens/smaller segment than posterior segment Iris divides segment into two chambers: anterior and posterior chambers Contains aqueous humor

Answer 63

Anterior segement

Question 64

Chamber between cornea and iris

Answer 64

Anterior chamber

Question 65

Chamber between iris and lens

Answer 65

Posterior chamber

Question 66

Continuously formed by capillaries of ciliary processes (unlike vitreous humor) Supplies nutrients and oxygen mainly to lens and cornea but also to retina, and removes wastes Drains scleral venous sinus at sclera-cornea junction

Answer 66

Aqueous humor

Question 67

Drainage of aqueous humor is blocked, causing fluid to back up and increase pressure within eye Symptoms: halos around lights and blurred vision

Answer 67

Glaucoma