The Eyeball Anatomy

Question 1

what are the 3 layers of the eyeball

Answer 1

fibrous
vascular
inner

Question 2

what 2 parts make up the fibrous layer

Answer 2

the sclera and the cornea

Question 3

functions of the sclera and cornea

Answer 3

give shape and support to the eye

attachment site for extra-ocular muscles (sclera)

refracts light entering the eye (cornea)

Question 4

what 3 parts make up the vascular layer (aka the urea)

Answer 4

Choroid
Ciliary body
Iris

Question 5

what is the choroid

Answer 5

a layer of connective tissue and blood vessels which surrounds the outside of the eye

provides nourishment for the outer layers of the retina

site of nutrition and gas exchange

Question 6

what is the ciliary body

Answer 6

the ciliary muscle and the ciliary processes - encircles the lens

ciliary muscles - smooth muscle fibres

ciliary processes - attach the lens to the ciliary body via zonula fibres

Question 7

function of the ciliary body

Answer 7

changes the shape of the lens (accommodation)

secretes aqueous humour

Question 8

what happens to the lens when the ciliary muscle is relaxed

Answer 8

the suspensory ligaments are taut

the lens is therefor stretched out and thin to help with distant vision

Question 9

what happens to the lens when the ciliary muscle is contracted

Answer 9

the suspensory ligaments relax

the lens goes back to being pump and circular - thick and focussed to help with close vision

Question 10

what is the iris

Answer 10

a circular structure an open space in the middle - the pupil

vascular and gives eye colour

controls the size of the pupil

Question 11

how does the iris control the size of the pupil

Answer 11

The spinchter papillae muscle (parasympathetic) shrinks the pupil in response to light

the dilator papillae muscle (sympathetic) dilates the pupil in response to dark

Question 12

what type of innervation is the dilator papillae muscle

Answer 12

sympathetic

‘fight or flight’ wide eye

Question 13

what makes up the inner layer of the eye

Answer 13

the retina - this is the light detecting part

Question 14

what are the 2 layers of the retina

Answer 14

neural layer
-consists of photoreceptors

pigmented layer

• underneath neural layer - attached to choroid layer
• supports neural layer

Question 15

what is the non-visual retinal

Answer 15

anterior part of the eye where the pigmented layer continuous but the neural layer does not

Question 16

what is the optic part of the retina

Answer 16

posteriorly and at the sides where both layers of the retina are present (seen in fundoscopy)

Question 17

what is the centre of the Retina

Answer 17

the MACULA

Question 18

what is in the macula

Answer 18

v pigmented
high concentration of CONES
responsible for high accuracy colour vision

Question 19

what is the optic disc

Answer 19

area where the optic nerve and central retinal artery enter the Retina

had no light detecting cells - blind spot of the Retina

Question 20

what vessel supplies the retina

Answer 20

central retinal artery

enters at the optic disc

branches views in ophthalmoscopy

Question 21

where is the anterior chamber

Answer 21

between the cornea and the iris

Question 22

what does the anterior chamber contain

Answer 22

aqueous humour

Question 23

where is the posterior chamber

Answer 23

small chamber behind the iris and in front of the lens

Question 24

what does the posterior chamber contain

Answer 24

aqueous humour

Question 25

what connects the posterior and anterior chambers

Answer 25

pupillary opening

Question 26

where is aqueous humour first secreted

Answer 26

into the posterior chamber - then transmitted to anterior chamber via the pupil

Question 27

how is aqueous humour drained

Answer 27

via the trabecular meshwork into the canal of schlep

Question 28

what happens if the drainage of aqueous humour is obstructed

Answer 28

pressure builds up leading to glaucoma - as the optic nerve can be damaged by the rise in pressure

Question 29

what is the vitreous chamber

Answer 29

a chamber on the other side of the lens - it secretes vitreous humour and extends behind the lens to the retina

Question 30

what is the centre of the macula

Answer 30

the fovea