Session 8- Functional Anatomy of the orbit, eye and ocular muscles

Question 1

what is the orbit

Answer 1

a bony pyramid housing the eyeball, its muscles, nerves vessels and most of the lacrimal apparatus

Question 2

which are the weakest walls of the orbit

Answer 2

inferior and medial making them most vulnerable to fracture

Question 3

what does fracture of the orbit lead to

Answer 3

a sudden increase in introrbital pressure and is often the floor that fractures

Question 4

what makes the medial wall stronger than the inferior wall

Answer 4

although it is thinner than the inferior wall the presence of the walled air cells act as buttresses and convey an added strengh to the medial wall

Question 5

what becomes infected in acute sinusitis

Answer 5

walled ethmoidal air cells

Question 6

what travels through the inferior orbital fissure

Answer 6

infraorbital nerve- branch of Vb

inferior opthalmic vein

Question 7

what series of holes are at the apex of the orbit

Answer 7

optic canal
superior orbital fissure
inferior orbital fissure

Question 8

what is the transparant continuation of the sclera

Answer 8

cornea

Question 9

what does the sclera provide in terms of attachemnt

Answer 9

extra-ocular muscles

Question 10

what thin transparent layer of the cells cover the sclera

Answer 10

conjunctivae

Question 11

treatment of conjuctivitis

Answer 11

reassurance
hygeine advice
short course of chloramphenicol eye drops

Question 12

what is a cause of conjuctivitis in the neonatal period

Answer 12

an infective organism like chlamydia picked up from the mother’s vaginal mucosa during birth

treated with erythromycin

Question 13

what causes subconjuctival haemorrhage

Answer 13

when one of the small conjuctival blood vessels rupture and the blood escapes under the transpareny conjunctival layer

Question 14

what does the choroid continue as anteriorly

Answer 14

cilary body and iris

Question 15

what does the cilary body consist of

Answer 15

cilary process and muscle

Question 16

function of cilary body

Answer 16

connects choroid and iris

Question 17

what alerts you with a red eye

Answer 17

if it is painful as this indicates a serious underlying cause
uveitis

Question 18

what is uveitis

Answer 18

inflammation of the choroid layer

Question 19

what is the uvea

Answer 19

collective term for choroid, cilary process and iris

Question 20

what does the outer layer o the eyeball consist of

Answer 20

sclera

cornea

Question 21

what does the middle layer of the eueball consist of

Answer 21

choroid
cilary body
iris

Question 22

what does the innerlayer of the retina consist of

Answer 22

neurosensory cell layer

pigmented epithelial cell layer

Question 23

what layers are within the retina

Answer 23

neurosensory cell layer

pigmented epithelial cell layer

Question 24

where does the pigmented epithelial layer lie

Answer 24

betweem the choroid and neurosensory layer of the retina

Question 25

what is the role of the melanin in the pigmented epithelial cells

Answer 25

helps absorb scatterd light that has passed into the eye

Question 26

function of neurosensory layer

Answer 26

area of the retina that senses light and where photoreceptors are found

Question 27

what are the cones responsible for

Answer 27

high visual acuity and color vision

Question 28

where are the cones concentrated

Answer 28

macula

Question 29

how does the macula appear on fundoscopy

Answer 29

darker | lying lateral to optic disc

Question 30

what is the centre of the macula called

Answer 30

fovea

Question 31

what is present in the fovea

Answer 31

small area where the only photoreceptors are cones

Question 32

what causes colour blindness

Answer 32

absence of dysfunction of one of the red green or blue cone leads

Question 33

what is the function of rods

Answer 33

responsible for vision in low intensity ligjt and do not discern colours

Question 34

where are rods abundant

Answer 34

peripheral parts

Question 35

what is the optic disc

Answer 35

accumulation of retinal axons making it devoid of photoreceptors making it the blind spot

Question 36

what are the three chambers of the eyeball

Answer 36

anterior, posterior and virteous chamber most posteriorly

Question 37

what is the virteous chamber filled with

Answer 37

transparent, jelly like virteous humour

Question 38

what are the anterior and posterior chambers filled with

Answer 38

transpaarent liquid called aqeuos humour

Question 39

where is the anterior chamber

Answer 39

space between the cornea and iris

Question 40

where is the posterior chamber

Answer 40

space between the iris and lens where the cillary body and processes are found

Question 41

what is aqueous humour important for

Answer 41

supporting the shape of the eyeball by the pressure it exerys provides nourishment to the lens and cornea

Question 42

where does aqueous humour drain

Answer 42

irido-corneal angle into the canal of schlemm via a trabecular meshwork and subsequently back into venous circulation

Question 43

what happens to the deainage of aqueous humor as we age

Answer 43

it can become obstructed which leads to a ris ein intra-ocular pressre leading to glaucoma

Question 44

what is glaucoma

Answer 44

irreversible damahe and death of optic nerve

Question 45

what is the most common type of glaucoma

Answer 45

open-angle glaucoma

Question 46

what causes open angle glaucoma

Answer 46

blockage within the trabecular meshwork

Question 47

why is open angle glaucoma hard to pick up

Answer 47

it develops painlessly and insidiously over time

Question 48

what is closed angle glaucoma

Answer 48

when the irido-corneal angle is narrowed by the peripheral edge of the iris access to trabecular meshwork is blocked off rise in intraocular presuure

Question 49

how does closed angle glaucoma present

Answer 49

``` sudden onset of a painful red eye blurred vision fixed sluggish semi-dilated irregular oval shaped pupil nausea vomiting eye feels hard to palpate ```

Question 50

what muscles form the iris

Answer 50

spinchter and dilator pupillae which are under the control of the ANS

Question 51

what supplies nutrients to the lens

Answer 51

aqueous humour

Question 52

what is cataracts

Answer 52

degredation of the proteins in the lens causes it to become clouded and less transparent

Question 53

how is the shape of the lens altered

Answer 53

contraction of the ciliary muscle under the influence of the PNS alters the tension in the suspensory ligaments

Question 54

From what artery does the arteries in the optic disc arise from

Answer 54

Central retina,