Eyeball

Question 1

The eyeball is located in the bony socket called the ________

Answer 1

Orbit

Question 2

The ADNEXA (accessory ocular structures of the eye) are

Answer 2

Palpebrae (eyelid)
Third eyelid and conjunctiva
Lacrimal apparatus

Question 3

What are the tunics of the eye

Answer 3

Fibrous
Vascular
Retinal

Question 4

The fibrous tunic is made of of what three things?

Answer 4

Sclera
Cornea
Limbus (corneoscleral junction)

Question 5

What is the sclera

Answer 5

Posterior portion of the eye

White opaque layer of dense irregular CT

Question 6

What is the function of the sclera

Answer 6

Protect
Maintain shape
Insertion point for extraocular muscle s

Question 7

What is the cornea?

Answer 7

Anterior portion of the eye

Avascular and transparent convex-concave lens

Question 8

What are the 5 layers of the cornea??

Answer 8

1 Anterior corneal epithelium (stratified squamous)
2 Anterior limiting lamina/ subepithelial basement membrane (parallel collagen fibers)
3 substantia propria -corneal stroma
4 posterior limiting lamina- Descemets membrane
5 posterior epithelium of cornea

Question 9

What factors contribute to corneal transparency

Answer 9

Avascular
Collagen arrangement
Proteoglycans between collagen
Na+ pumps to transport water out

Question 10

What is the limbus?

Answer 10

Corneoscleral junction

Where the opaque sclera overlaps the transparent cornea

Question 11

The vascular tunic of the eye is composed of?

Answer 11

Iris
Iridocorneal angle
Ciliary body
Choroid

Question 12

The stroma of the iris is made of of what?

Answer 12

Pigmented loose connective tissue and Iridial melanin

Question 13

The posterior epithelium of the iris contains ___________________ in equids and ruminants

Answer 13

Iridic granules (corpora nigra)

Question 14

The ______________ lies at the convergence of the corneoscleral junction and ciliary body

Answer 14

Iridocorneal angle

Question 15

The Iridocorneal angle is composed of ? What is its purpose?

Answer 15

Pectinate ligaments
Trabecular mesh work
And trabecular veins

This is the draining point for aqueous humor

Question 16

The anterior expansion of the choroid at the level of the lens is the _________

Answer 16

Ciliary body

Question 17

What is the mechanical function of the ciliary body?

Answer 17

Contracts to reduce tension in zonular fibers of the lens

Question 18

Describe the epithelial surface of the ciliary processes of the ciliary body

Answer 18

Non pigmented -ion transporting forming aqueous humor

Pigmented- basement membrane extends to form zonular fibers that suspend the lens

Question 19

Hwo does the iris transition into the ciliary body?

Answer 19

Posterior pigmented epithelium is continuous with the non-pigmented epithelium of the ciliary body

Question 20

Aqueous humor occupies what space?

Answer 20

Anterior and posterior chambers

Question 21

What is the drainage pathway for aqueous humor ?

Answer 21

Posterior chamber -> pupil -> Anterior chamber -> iridocorneal angle -> pectinate ligaments -> scleral venous plexus

Question 22

What is the choroid?

Answer 22

Posterior portion of the vascular tunic

Question 23

The anterior portion of the choroid is continuous with the _____________

Answer 23

Ciliary body

Question 24

The dorsal part of the choroid is made of what?

And what is its purpose

Answer 24

Tapetum lucidum

Increase light perception under conditions of poor illumination

Question 25

The neuroepithelial/ retinal tunic is made up of which three parts?

Answer 25

Sensory/optical part Non-sensory/ciliary part Non-sensory/iridal part

Question 26

The sensory/ optical retina is in contact with what layer of the eye?

Answer 26

Choroid

Question 27

What holds the retinal tunic in place?

Answer 27

Vitreous body

Question 28

What are the layers of the sensory/optical retina?

Answer 28

``` Optic nerve fibers Ganglionic layer Inner plexiform layer Inner nuclear layer Outer plexiform layer Cell bodies of rods and cones Photoreceptors layer Pigment cells ```

Question 29

What is the pathway of optical nerve impulse travel?

Answer 29

Light passes through retina to stimulate the photoreceptors cells (rods and cones) Impulse passes to bipolar neurons To ganglion cells Axons of ganglion cells for nerve fiber layer and converge at optic disk

Question 30

What is the path of light to the retina

Answer 30

``` Through tear film Cornea Aqueous humor Pupil Lens Vitreous humor First 8 layers of retina Rods and cones Absorbed by retinal epithelium ```

Question 31

Retinal pigmented epithelium

Answer 31

Outermost layer of retina Flat polygonal cells resting on a BM Transport of nutrients and metabolites to the rods and cones

Question 32

Compare rods and cones

Answer 32

Rods - inner segment long and thin - flattened membranous disk with Rhodopsin - dim light vision Cones - inner segment has broad base - disks with Iodopisn - bright light and colour vision

Question 33

Where does retinal detachment occur?

Answer 33

Between rods and cones and pigmented retinal epithelium

Question 34

What is the vitreous body made of??

Answer 34

Water and hyaluronic acid Gel cortex with liquid center

Question 35

What is the structure of the lens?

Answer 35

Entirely surrounded by capsule - thicker on anterior surface

Question 36

What suspends the lens

Answer 36

Zonular fibers

Question 37

The anterior epithelium of the lens is made up of ______________ cells which become elongate at the equator

Answer 37

Simple cuboidal

Question 38

The anterior epithelium cells differentiate into?

Answer 38

Elongate lens fibers -prism like cells that lack nuclei and have many gap junctions

Question 39

The eyelid is made up of?

Answer 39

``` Conjunctiva Cilia (eyelashes) Tarsal (meibomian) glands Third eyelid (nictitating membrane) Lacrima (tear) apparatus ```

Question 40

The __________ conjunctiva lines the inner eyelid and the ____________ conjunctiva lines the sclera

Answer 40

Palpebral | Bulbar

Question 41

Conjunctiva is a _______________ epithelium

Answer 41

Pseudostratified columnar or transitional that becomes squamous at eyelid margin

Question 42

What is the purpose of the third eyelid?

Answer 42

Protects eye | Remove foreign material

Question 43

The third eyelid is a fold of the __________ formed by hyaline cartilage (ruminants) and elastic cartilage (dog)

Answer 43

Conjunctiva

Question 44

What are located under the conjunctival surface?

Answer 44

Lymphatic nodules

Question 45

Lacrimal glands are _________________ acini composed of serectory granular cells

Answer 45

Tubuloalveolar seromucinous

Question 46

Tears are produced by which three glands?

Answer 46

Meibomian (tarsal) - oily superficial Lacrimal - sero-mucous (from third eyelid) Mucous - from goblet cells of conjuring