Special senses - eyes

Question 1

What is the retina also known as?

Answer 1

Nervous tunic

Question 2

What are the two layers of the retina called?

Answer 2

Pars ceca retina

Pars optica retina

Question 3

What is the pars ceca retina?

Answer 3

Outer pigmented layer

Not photosensitive

Question 4

Where do the pars ceca retina and pars optica retina arise from?

Answer 4

Optic nerve and fundus

Question 5

What is the fundus?

Answer 5

Rounded portion at the back of the eye

Question 6

Where does the pars ceca retina line and terminate at?

Answer 6

Lines the posterior iris and ciliary body

terminates at the pupillary margin

Question 7

What is the pars optica retina?

Answer 7

Inner non pigmented area

Contains the photosensitive rods and cones

Question 8

Where does the pars optica retina terminate?

Answer 8

Ora serrata - ridge further back than the cornea

Question 9

What is the area of maximum optic resolution called?

Answer 9

Macula

Question 10

What is the area where the optic nerve forms called?

Answer 10

Optic nerve

Question 11

What are the cells found in the pars optica retina?

Answer 11

Ganglion cells
Amacrine cells
Horizontal cells
Bipolar cells
Muller cells

Question 12

What are muller cells?

Answer 12

Glial cells

Question 13

What is the outer capsule of the lens made up of?

Answer 13

Elastic fibres

Question 14

How does the lens change shape?

Answer 14

Zonular fibres and suspensory ligaments attach the outer capsule of the lens to the ciliary body which constricts and relaxes

Question 15

What is the inner substance of the lens made up of?

Answer 15

Hard nucleus of concentric sheets of fibres joining at Y shaped sutures

Question 16

What are the different chambers of the eye?

Answer 16

Anterior chamber
Posterior chamber
Vitreous chamber/body

Question 17

What fluid is found in the anterior and posterior chambers?

Answer 17

Aqueous humour

Question 18

What fluid is found in the vitreous chamber/body and what does it do?

Answer 18

Vitreous humour - pads out eye

Question 19

What embryological structure is found in the vitreous chamber and why?

Answer 19

Hyaloid canal - hyaloid artery travels through it and supplies the developing lens in embryo

Question 20

Where is the anterior chamber located?

Answer 20

Between the cornea and the iris

Question 21

Where is the posterior chamber located?

Answer 21

Between the iris and the lens

Question 22

Where is aqueous humour produced?

Answer 22

Posterior chamber

Question 23

Where is the vitreous chamber located?

Answer 23

Between the lens and the retina

Question 24

What is the vascular layer of the eye called?

Answer 24

The choroid

Question 25

Where is the tapetum lucidum located?

Answer 25

Part of the choroid layer | In the fundus

Question 26

What animal doesnt have a tapetum lucidum?

Answer 26

Pig

Question 27

What does the tapedum lucidum do?

Answer 27

Reflects light back onto retina a second time so better sight in night

Question 28

What is a deviated eye called?

Answer 28

Strabismus

Question 29

What is a collie eye defect?

Answer 29

Colour diluted eye | No tapetum lucidum

Question 30

What does a fundus of a small ruminant look like?

Answer 30

Twisted vessels

Question 31

What feature is specific to a calf retina?

Answer 31

Ring of myelinated fibres around perifery of optic disc

Question 32

How does diabetes cause cataracts?

Answer 32

High blood glucose increases sorbitol inside lens which causes osmosis, cell swelling and death

Question 33

Where does the eye arise from?

Answer 33

Neuroectoderm

Question 34

What area of the neural plate form the optic vesicles?

Answer 34

Optic sulci

Question 35

What form from the optic sulci?

Answer 35

Optic vesicles which form the eyes

Question 36

What does contact of the optic vesicles with the ectoderm form?

Answer 36

Lens placode

Question 37

What is formed from invagination to form the lens and vitreous structures?

Answer 37

Optic cup

Question 38

What is collie eye anomaly?

Answer 38

Congenital inherited disease, causes blindness, hypoplasia of the retina

Question 39

What is a defect of the closing of the cup structures forming the iris called?

Answer 39

Coloboma

Question 40

What is it called when the embryonic vascular network of the eye doesnt break down?

Answer 40

Persistent pupillary membranes

Question 41

Where are the anterior and posterior poles of the eye?

Answer 41

Highest point on cornea and posterior surface

Question 42

Where is the optic axis?

Answer 42

Between the two poles

Question 43

What are the 3 main layers/tunics of the eye?

Answer 43

External fibrous tunic Middle vascular tunic Internal nervous tunic

Question 44

What are the 3 features of the external fibrous tunic?

Answer 44

Cornea Sclera Limbus

Question 45

What is the cornea?

Answer 45

Front of eye, avascular and transparent

Question 46

What is the sclera?

Answer 46

Dense collagen with blood vessels

Question 47

What is the area of the sclera where the optic nerve passes called?

Answer 47

Cribiform region

Question 48

What is the limbus?

Answer 48

Junction between the sclera and the cornea

Question 49

What is a deep corneal ulcer called?

Answer 49

Descemetocele

Question 50

What are the scleral blood vessels called?

Answer 50

Long and short posterior ciliary arteries | Anterior ciliary arteries

Question 51

Where do the scleral blood vessels arise from?

Answer 51

External opthalmic artery

Question 52

What is another name for the vascular tunic?

Answer 52

Uvea

Question 53

What are the 3 features of the vascular tunic?

Answer 53

Choroid Ciliary body Iris

Question 54

What causes constriction of the iris?

Answer 54

Oculomotor nerve - parasympathetic

Question 55

What feature of the iris is found in ungulates?

Answer 55

Iridic granules - reduces glare/brightness

Question 56

Where is the ciliary body located?

Answer 56

Opposite limbus

Question 57

How does aqueous humour leave the anterior and posterior chambers?

Answer 57

Pectinate ligament

Question 58

Where does aqueous humour drain into?

Answer 58

Scleral venous sinus

Question 59

What divides the anterior and posterior chambers?

Answer 59

Iris

Question 60

What affects drainage of the aqueous humour?

Answer 60

Iridocorneal angle

Question 61

What supplies sympathetic innervation to the vascular tunic?

Answer 61

Cranial cervical ganglion

Question 62

What does the sympathetic fibres innervate?

Answer 62

Orbital muscle and dilator of pupil

Question 63

What do the sympathetic fibres follow to the orbit?

Answer 63

Opthalmic branch of trigeminal nerve

Question 64

What do the parasympathetic fibres innervate in the eye?

Answer 64

Constrictor of pupil and ciliary muscle