Orbit and eyes

Question 1

What are the supraorbital margins and the infrorbital margins?

Answer 1

Supraorbital: Frontal bone

Infrorbital margin: zygomatic bone (laterally) and maxilla (medially)

Question 2

What makes up the bones of the orbit?

Include the ROOF, FLOOR, LATERAL WALL, MEDIAL WALL?

Answer 2

ROOF: frontal bone, lesser wing of sphenoid
FLOOR: maxilla, zygomatic, palatine
LATERAL: Zygomatic, greater wing of sphenoid
MEDIAL: Maxilla, lacrimal bone, ethmoid, body of sphenoid

Question 3

What is the sclera?

Answer 3

Forms 5/6th of the eyeball

Question 4

What does the sclera provide attachments for?

Answer 4

The EOMS

Question 5

What is the cornea?

Answer 5

The principal refracting component of the eye

Question 6

What is special about the cornea which makes it good for vision?

Answer 6

Avascular and transparent, optimum for vision

Question 7

What are layers of the cornea?

Answer 7

Epithelium
Bowman's layer
Stroma
Descemet's membrane
Endothelium

Question 8

How much of the eye does the cornea take up?

Answer 8

Anterior 1/6th

Question 9

What makes the cornea transparent?

Answer 9

Collagen fibrils uniform in diameter and evenly spaced

Question 10

What are the bundles in the cornea called??

Answer 10

Lamellae

Question 11

What are the factors which affect scleral opacity?

Answer 11

Composition of the stroma
hydration
Size and distribution of the collagen

Question 12

What is the significance of the anterior chamber and angle?

Answer 12

The aqueous humour drains out

Question 13

What is the anterior chamber angle??

Answer 13

It is the junction between iris and cornea

Question 14

Name the key structures in the anterior chamber angle?

Answer 14

Cornea
Trabecular meshwork
Canal of schlemm
Ciliary body

Question 15

Uvea is which coat of the eye?

Answer 15

Middle!

Question 16

Why is the ciliary body important?

Answer 16

Forms aq humour
Tether lens
accomodation

Question 17

Why is Aq Humour important?

Answer 17

Maintaining health of lens and cornea

Creates intraocular pressure

Question 18

What forms the aq humour?

Answer 18

Cilliary epithelial cells

Question 19

What allows accommodation in the eye?

Answer 19

Cilliary muscle

Zonules that attach to lens

Question 20

What are the zonules?

Answer 20

Zonules are ligaments which attach the ciliary body to the eye (in between)

Question 21

Contraction of the ciliary body causes?

Answer 21

Increases width of lens allows accomodation

Question 22

Presbyopia, define it?

Answer 22

Loss of accommodation due to aging

Question 23

What is the cause of presbyopia

Answer 23

Age reduces the flexibility in the lens capsule and zonules

Question 24

What is the Iris?

Answer 24

Aperture of eye

Question 25

What are the two muscles of the iris?

Answer 25

``` Sphincter pupillae (pns) Dilator pupillae (sns) ```

Question 26

What is the choroid of the eye?

Answer 26

Choroid are 3 layers of blood vessels, most important is the choriocapillaris which sits belwo the retina and provide nutrients

Question 27

What is the specialized region of the retina called?

Answer 27

Fovea

Question 28

What is the function of the fovea?

Answer 28

High visual acuity, avascular and high density of cones

Question 29

Which artery supplies the orbit?

Answer 29

The tributaries of the opthalmic artery and the central retinal artery Ciliary arteries

Question 30

What is the dual supply to the retina?

Answer 30

Posterior ciliary artery supplies the outer retina and the central retinal artery supplies the inner retina

Question 31

What are the main muscles of the orbit?

Answer 31

Oribcularis oculi | levator palpebra superiosis

Question 32

Function of levator palpebrae superiorsis

Answer 32

Elevate upper lid | CNIII

Question 33

Funcction of orbicularis oculi

Answer 33

Sphincter Depresses upper lid FACIAL NERVE

Question 34

What are the 3 layers of the eye?

Answer 34

Cornea, sclera Uvea: ciliary body, iris, choroid Retina, optic nerve