Eye Flashcards Preview

RUSVM Anatomy 2 > Eye > Flashcards

Flashcards in Eye Deck (39)
Loading flashcards...
1

What is the function of the orbit?

Protects eye and adexa, & serves as attachment site for extrinsic muscles

2

Bones of the orbital margin:

frontal, maxillary, zygomatic, lacrimal, ethmoid

3

The bony orbit is complete in the horse, ox, and goat. What does this mean?

the temporal process of the frontal bone joins the zygomatic arch to complete the orbit

4

What completes the orbit in the dog?

orbital ligament- spans the region b/t the zygomatic process of the frontal bone and the frontal process of the zygomatic bone

5

Structures contained within the orbit:

periorbita, eyeball, ocular adnexa, trochlea

6

Periorbita

cone-shaped sheath of connective tissue that surrounds the caudal eyeball and ocular adnexa

7

Ocular adnexa

accessory structures for protection (palpebrae, third eyelid, conjunctiva, retrobulbar fat), tear production (lacrimal gland/appartatus, gland of third eyelid), blood supply and innervation

8

Trochlea

-a pulley-shaped cartilage that is attached to the dorsomedial wall of the orbit
-directs the course of the dorsal oblique muscle

9

Three tunics of the eye:

Tunica externa (fibrous tunic)
Tunica media (vascular tunic, choroid)
Tunica interna (retina)

10

Fibrous tunic:

-comprised of two regions: Cornea (transparent anterior 1/4) & Sclera (opaque posterior 3/4)
-continuous w/ dural layer of the CNS

11

Vascular tunic

Composed of 3 regions:
-Choriod
-Ciliary body
-Iris
Continuous w/ pia-arachnoid layers of the CNS

12

Choriod

-highly vascularized and pigmented; provides nourishment to globe
-black areas for light absorption
-tapetum lucidum is a brightly colored region, located superior to the optic disk, that reflects light

13

Ciliary body

ciliary mm. and ciliary ligaments control the shape of the lens

14

Iris

circular and radial mm. regulate the size of the pupil

15

Iridic granulae

horse has "black bodies" (sunglasses) on pupillary margin

16

Internal tunic

the retina, divided into two regions:
-Optical part (visual part covers the choroid)
-Blind part (non-visual part, covers ciliary body and iris) Cannot distinguish blind retina from ciliary body

17

The optic retina has two layers:

-pigmented (outer) layer (stratum pigmentosum)
-nervous (inner) layer (pars nervosa retina) divided into nine layers
*divisions of retina can only be seen histologically

18

The neuron processes of the ganglion cells of the retina converge to form the

optic nerve

19

Ganglion cells

-bi-polar neurons whose cell bodies are located within the ganglion cell layer of the retina

20

The optic nerve begins at the ______

optic disk, where these axonal processes exit the caudal aspect of the globe of the eye
"blind spot"
-retinal vessels also enter & leave here

21

Anterior compartment

-located b/t the lens and cornea
-filled with aqueous humor
-divided by the iris into 2 chambers:
anterior chamber and posterior chamber

22

Posterior compartmenT

-Located b/t the lens and fundus
-Contains the vitreous body
-helps maintain shape of eye
-maintains necessary intraocular pressure to prevent retinal detachment

23

Vitreous body

-established during development and is maintained w/in the posterior compartment of the eye to maintain intraocular pressure
-degeneration (liquefaction) of the vitreous body may predispose to retinal detachment

24

Aqueous humor

-continuously produced and reabsorbed
-secreted by ciliary body epithelium
-drained via the venous sinuses of the sclera at the iridocorneal angle
-increased fluid results in increased intraocular pressure (glaucoma)

25

Intrinsic muscles of the eye

ciliary muscles and pupillary muscles

26

Ciliary Muscles

-regulates shape of the lens
-contraction relaxes tension of the suspensory ligaments and the lens fattens (accommodation)
-regulated by the oculomotor nerve (PSNS)

27

Pupillary muscles

-constrictor pupillae (circular)
-regulated by the oculomotor by the oculomotor nerve (PSNS)
-Dilator pupillae (linear, radial)
-regulated by the SNS (neuron processes from cranial cervical ganglion)

28

Adnexa of the eye

-Palpebrae: superior and inferior eyelids- palpebral fissure is the space b/t these
-conjunctiva: palpebral and bulbar; continuous at the fornix
-third eyelid: cartilage, superficial gland of the third eyelid
-Lacrimal appartaus
-Extrinsic muscles of the globe

29

Both eyelids (palpebrae) are lined by haired skin externally and ____ internally

mucous membrane

30

What anchors the commisures of the eyelids?

Medial and lateral palpebral ligaments
-medial ligament is more developed