Lecture 33: Eye

Question 1

Answer 1

1. levator palpebrae superioris muscle
   2.tarsal plate
   3.cornea
   4.conjunctiva

Question 2

what is inner surface of eyelids lined with

Answer 2

conjunctivate. specialized mucous membrane. note: doesn;t cover cornea

Question 3

tarsal plate

Answer 3

2 in image

cartilage forming the skeleton of eyelid.

provides insertion point for levator palpebrae superioris

sebaceous glands embedded in plates

Question 4

levator palpebrae superioris nerve supply

Answer 4

CNIII and sympathetic fibres

Question 5

cornea

Answer 5

anterior transparent part eyeball

Question 6

Answer 6

1. ciliary body
   2.suspensory lig
2. pupil
   4.cornea
   5.iris

Question 7

what are the 3 layers of eyeball from outside to inside

Answer 7

1. Fibrous layer: made of fibrous tissue. Most of posterior part of fibrous layer (5/6) is made of dense irregular connective tissue = sclera. This layer is there to mechanically protect eyeball. Attachment site for E.O. muscles
   * Anterior 1/6 of fibrous layer turns into clear/transparent layer=cornea. Clear due to Due to arrangement collagen fibres AND no blood vessel flowing into it
   2. Vascular layer: posterior 5/6 is called choroid. Brings blood vessels to nourish retina
      
      • Anteriorly divides into:
        § Ciliary body: made of smooth muscle fibres.
        □ Attached to lens by suspensory ligaments- hold lens in place and change convexity of lens
        § Iris: made of smooth muscle fibres.
        □ At center of iris= pupil
        □ Fxn iris= expand or reduce size of pupil
   3. Nervous layer: posterior 3/4 is called retina. Loaded with photoreceptors convert light to nerve impulses
      
      • Anterior 1/4 is pigmented epithelium. Covers ciliary body. Lines posterior surface iris.
        § Determines colour of eye
        § No pigment= blue eyes
        Optic nerve (CNII) axons retina

Question 8

fibrous layer of eyeball

Answer 8

1. Fibrous layer: made of fibrous tissue. Most of posterior part of fibrous layer (5/6) is made of dense irregular connective tissue = sclera. This layer is there to mechanically protect eyeball. Attachment site for E.O. muscles
   * Anterior 1/6 of fibrous layer turns into clear/transparent layer=cornea. Clear due to Due to arrangement collagen fibres AND no blood vessel flowing into it

Question 9

vascular layer eyeball

Answer 9

=middle layer

2. Vascular layer: posterior 5/6 is called choroid. Brings blood vessels to nourish retina
   * Anteriorly divides into:
   § Ciliary body: made of smooth muscle fibres.
   □ Attached to lens by suspensory ligaments- hold lens in place and change convexity of lens
   § Iris: made of smooth muscle fibres.
   □ At center of iris= pupil
   □ Fxn iris= expand or reduce size of pupil

Question 10

nervous layer eyeball

Answer 10

=inner

3. Nervous layer: posterior 3/4 is called retina. Loaded with photoreceptors convert light to nerve impulses
   * Anterior 1/4 is pigmented epithelium. Covers ciliary body. Lines posterior surface iris.
   § Determines colour of eye
   § No pigment= blue eyes
   Optic nerve (CNII) axons retina

Question 11

is pupil dilated by symp or para?

Answer 11

symp! maximized light entry into eye

Question 12

Answer 12

1. macula lutea
2. optic disk
3. fovea centralis

Question 13

blind spot

Answer 13

=optic disk

no PRs

Question 14

macula lutea

Answer 14

“yellow spot”
at centre is fovea centralis- higest [PRs]

Question 15

blood supply eye

Answer 15

choroid

Question 16

what happens to lens when looking at near object

Answer 16

lens is super convex.
ciliary body contracts
suspensory ligaments are loose

PSN

Question 17

what happens to lens when looking at far object

Answer 17

ciliary body relaxed
lens is flat

sympathetic NS causes this

Question 18

what muscles is iris comprised of

Answer 18

2 sets smooth muscles:

1. sphincter pupillae aka circular. reduce pupil size. PSN stimulates
2. dilator pupillae/radial muscles, symp

Question 19

Answer 19

1.scleral venous sinus
2. anterior chamber
3.ciliary body
4.posterior chamber
5. vitreous chamber

Question 20

space btw cornea and iris

Answer 20

ant chamber

Question 21

space btw iris and lens

Answer 21

post chamber

Question 22

what connects anterior and posterior chamber

Answer 22

pupil

Question 23

what is purpose of anterior and posterior chamber

Answer 23

Both chambers filled with aqueous humour. Produced by ciliary body (to make sure cornea/lens are clear, they have no blood vessels) SO this aq. Humor nourishes cornea/lens

Question 24

venous drainage eye

Answer 24

scleral venus sinus at junction of cornea and sclera drains the aqeuous humour

Question 25

vitreous chamber

Answer 25

btw lens and retina filled with vitreosus fluid which shapes eyeball and cushions retina

Question 26

glaucoma

Answer 26

extra pressure in ant/post chambers --> transfers to retina thru vitreous body

Question 27

Answer 27

1.nasolacrimal duct 2.lacrimal canaliculus 3.lacrimal gland 4.lacrimal sac

Question 28

lacrimal gland

Answer 28

upper lateral corner eye. produces tears. controlled by CN VII

Question 29

where do tears go after being produced by lacrimal gland

Answer 29

collected in lacrimal sac. in medial corner eye

Question 30

lacrimal canaliculus

Answer 30

two ducts which drain from lacrimal lake to lacrimal sac

Question 31

where does lacrimal sac connect

Answer 31

nasolacrimal duct. drains tears to inferior meatus, nasal cavity

Question 32

which bones is lacrimal sac btw

Answer 32

lacrimal and maxilla

Question 33

what % of cerebral cortex is devoted to processing visual info

Answer 33

40

Question 34

sclera

Answer 34

posterior 5/6 fibrous layer. dense connective tissue. protects inner eyeball. attchment site for EOM

Question 35

cornea

Answer 35

ant. 1/6 fibrous layer transparent, no blood vessels, covered by conjunctiva. convex anteriorly, helps focus light on retina

Question 36

choroid

Answer 36

forms the posterior five sixth of the vascular layer and lines the inner surface of the sclera. It is highly vascularised and nourishes the retina. The choroid carries melanin pigments that absorbs the light rays and prevents the reflection of light within the eyeball.

Question 37

ciliary body

Answer 37

anterior continuation of choroid. secretes aq. humour, modifies convexity of lens

Question 38

iris

Answer 38

anterior 1/6 vascular layer. smooth muscles that determine amount light entering eyeball

Question 39

retina

Answer 39

posterior 3/4 of nervous layer

Question 40

what determiens colour of eye

Answer 40

anterior 1/4 of nervous layer. pigmented epithelium. covers ciliary body. lines posterior surface iris