Lecture 7: Orbit and eye

Question 1

Bones that makeup the bony orbit

Answer 1

-frontal
-sphenoid
-ethmoid
-lacrimal
-Palatine
-Maxilla
-zygomatic

Question 2

foramen in the bony orbit

Answer 2

-superior orbital fissure
-inferior orbital fissure
-optic canal

Question 3

3 layers of the eye

Answer 3

outer fibrous layer, middle vascular layer and inner neural layer

Question 4

wha is the outer fibrous layer composed of

Answer 4

Sclera and cornea

Question 5

what is the middle vascular composed of

Answer 5

Uvea: Iris, ciliary body, and choroid

Question 6

what is the inner neural layer composed of

Answer 6

Retina

Question 7

what colour is sclera

Answer 7

white

Question 8

Cornea

Answer 8

-first refraction of light entering eye
-directs light to lens
-avascular

Question 9

Sclera

Answer 9

-supportive outer white layer
-attachment site for extraocular muscles
-covered by mucous membranes (conjunctiva) to lubricate eye
-vascular

Question 10

Limbus

Answer 10

-transition zone between cornea and sclera

Question 11

what does the cilairy body do

Answer 11

-produces aqueous humour
-contains siliary muscles
-helps focus lens using zonular fibres and ciliary muscles

Question 12

Iris

Answer 12

-contains pupillary dilator and sphincter muscles
-controls pupil size depending on light and nervous system signals

Question 13

Lens

Answer 13

-focuses light on retina

Question 14

what muscles adjust to things near or far

Answer 14

ciliary muscles

Question 15

what happens to lens when ciliary muscle is relaxed

Answer 15

zonule fibres tighten, pulling lens flattened for focusing on distant objects

Question 16

what happens to lens when ciliary muscles contract

Answer 16

zonule relaxes, lens rounded for focusing on close objects and refracting more light

Question 17

what happens when you view a distant object

Answer 17

1. ciliary muscles relax
2. Zonular fibres tighten
3. lens flattens

Question 18

what happens when you view a near object

Answer 18

1. ciliary muscles contract
2. Zonular fibres relax
3. lens thickens/rounds

Question 19

true or false: when viewing near objects, the ciliary muscles contract, which relaxes the zonular fibres and thickens the lens

Answer 19

true

Question 20

Iris colour is determined by what

Answer 20

colour is determined by amount of melanin

Question 21

Sphincter Pupillae

Answer 21

-concentric muscle fibres
-constricts pupils when contracted
-PNS (stops light coming in)

Question 22

DIlator Pupillae

Answer 22

-muscle fibres run longitudinally
towards margins of iris
-enlarges pupil when contracted
-sympathetic NS (helps light in)

Question 23

what happens to eye when SNS signals sent OR in dim light

Answer 23

dilator pupil contracts

Question 24

what happens to eye when PNS signals sent OR in bright light

Answer 24

sphincter puppilae contract

Question 25

Choroid

Answer 25

-nourises retina -maintains eye temp and volume

Question 26

Retina

Answer 26

captures light to send to brain

Question 27

where is the sharpest vision

Answer 27

fovea bc most photoreceptor cells are here

Question 28

Macula (fovea in center)

Answer 28

most photoreceptor cells here

Question 29

Optic Disc

Answer 29

-where optic nerve exits the eye (optic nerve is made by retinal axons) -blind spot -no photoreceptors

Question 30

Ora Serrata

Answer 30

-anterior border of retina

Question 31

Optic Nerve

Answer 31

CN II: accumulation of retinal axons

Question 32

what layer is the sclera and cornea in

Answer 32

outer fibrous layer

Question 33

what layer is the iris, choroid and ciliary body in

Answer 33

middle vascular layer

Question 34

what layer is the retina in

Answer 34

inner neural layer

Question 35

Chambers of the eye

Answer 35

-Anterior Chamber -Posterior Chamber -Vitreous chamber

Question 36

what chambers does the anterior cavity consist of

Answer 36

-anterior chamber -posterior chamber

Question 37

what chamber does the posterior cavity consist of

Answer 37

vitreous chamber (largest)

Question 38

anterior chamber position

Answer 38

posterior to cornea but anterior to iris

Question 39

posterior chamber position

Answer 39

posterior to iris but anterior to lens

Question 40

vitreous chamber position

Answer 40

posterior to lens but anterior to retina

Question 41

what is the anterior chamber filled with

Answer 41

aqueous humour

Question 42

what is the posterior chamber important for

Answer 42

production and circulation of aqueous humour

Question 43

aqueous humour purpose

Answer 43

-maintains ocular eye pressure -replaced every 90 minutes

Question 44

contents of vitreous chamber

Answer 44

filled with gel-like vitreous humour

Question 45

purpose of vitreous humour

Answer 45

-maintains eye shape -nourishes eye -attached to retina firmly -makes up about 80% of eye volume -does not regenerate

Question 46

which muscle is responsible for opening the eyelid

Answer 46

levator palpebrae superioris

Question 47

where does the superior oblique sit in the orbit

Answer 47

medially

Question 48

which extraocular muscle does not originate with the rest

Answer 48

inferior oblique

Question 49

extraocular muscles

Answer 49

-superior recuts -lateral recuts -inferior oblique -inferior rectus -medial rectus -superior oblique -levator palpebrae superioris

Question 50

what does the superior oblique wrap through

Answer 50

the trochlea

Question 51

what CN enter the eye orbit

Answer 51

trochlear, abduces, optic and oculomotor

Question 52

which way does the superior rectus pull the eye

Answer 52

up

Question 53

which way does the lateral rectus pull the eye

Answer 53

rolls eye laterally

Question 54

which way does the inferior oblique pull the eye

Answer 54

up and out

Question 55

which way does the inferior rectus pull the eye

Answer 55

rolls eye down

Question 56

which way does the medial rectus pull the eye

Answer 56

rolls eye medially

Question 57

which way does the superior oblique pull the eye

Answer 57

down and out

Question 58

WHich muscles are innervated by the oculomotor nerve

Answer 58

medial rectus, superior rectus, inferior oblique, and inferior rectus

Question 59

which muscles are NOT innervated by the oculomotor nerve

Answer 59

-Lateral rectus (abducens) -Superior Oblique (trochlear)

Question 60

Lacrimal Apparatus

Answer 60

-system of glands and ducts -produces and drains lacrimal fluid

Question 61

lacrimal fluid

Answer 61

-lubricates eye surface -removes debris from eye -amount 1mL produced each day

Question 62

path of lacrimal apparatus

Answer 62

1. Lacrimal gland 2. Excretory lacrimal ducts 3. superior and inferior puncta (via blinking) 4. Superior and inferior lacrimal canaliculi 5. Lacrimal Sac 6. Nasolacrimal duct