Special Senses

Question 1

The fluid produced by the ciliary body that fills the anterior and posterior chambers.

Answer 1

Aqueous humor

Question 2

The component of the uvea that extends from the edge of the optic nerve to the pars plana.

Answer 2

Choroid

Question 3

• The component of the vascular tunic that produces aqueous humor and is the site of attachment for the ciliary processes and the lenticular zonules.

Answer 3

Ciliary body

Question 4

• The transparent, avascular structure in the anterior aspect of the eye that functions to transmit and refract light.

Answer 4

Cornea

Question 5

• The angle formed by the cornea and the root of the iris that is the entrance to the trabecular meshwork, the site of outflow of the aqueous humor.

Answer 5

Iridocorneal angle

Question 6

• The anterior most portion of the vascular tunic that functions as a moveable diaphragm between the anterior and posterior chambers.

Answer 6

Iris

Question 7

• The biconvex transparent crystalline structure that is the second refracting unit of the eye.

Answer 7

Lens

Question 8

• The biconvex transparent crystalline structure that is the second refracting unit of the eye.

Answer 8

Lens

Question 9

• The component of the nervous tunic of the eye containing photoreceptors for light.

Answer 9

Retina

Question 10

• The major component of the fibrous tunic in the eye.

Answer 10

Sclera

Question 11

The nerve exiting the posterior aspect of the globe that extends to the rest of the central nervous system.

Answer 11

Optic Nerve

Question 12

• The term for the vascular tunic of the eye.

Answer 12

Uvea

Question 13

• The gel like material that fills the vitreous chamber.

Answer 13

Vitreous humor

Question 14

The ________is composed of the cornea and sclera.

Answer 14

fibrous tunic

Question 15

is composed of the iris, ciliary body and choroid.

Answer 15

The vascular tunic

Question 16

is composed of the retina.

Answer 16

The nervous tunic

Question 17

Additional critical structures associated with the eye include the

Answer 17

lens, the aqueous humor, the vitreous humor and the optic nerve.

Question 18

The classic description of the retina includes 10 layers that, from the outside in, are as follows:

Answer 18

Retinal pigment epithelium (RPE)
Photoreceptor outer segments – Rods and Cones
Outer limiting membrane
Outer nuclear layer
Outer plexiform layer
Inner nuclear layer
Inner plexiform layer
Ganglion cell layer
Nerve fiber layer
Inner limiting membrane

Question 19

is neuroectodermal in origin and forms first as an optic vesicle and later invaginates to form the optic cup.

Answer 19

Retina

Question 20

The ______ is the homolog of the epithelium of the choroid plexus of the brain.

Answer 20

RPE( Retinal pigmented epithelium)

Question 21

receive input from the integrating neurons and transmit impulses to the brain. The axons of the ganglion cells form the nerve fiber layer and converge at the posterior pole of the eye to form the optic nerve

Answer 21

Ganglion cells (third neuron layer)

Question 22

These are the supporting cells of the retina, however they do not participate directly in the electrical impulse transmission. The nuclei of Muller cells lie in the inner nuclear layer among the nuclei of the bipolar neurons

Answer 22

Muller cells

Question 23

varies according to species. Some species lack retinal blood vessels entirely. The retinal blood vessels are located in the nerve fiber layer and nourish the only inner third of the retina. The outer 2/3 of retina nourished by choroidal vasculature. The pattern of retinal vessels varies among species, but in all species retinal vessels originate from or directly adjacent to the optic nerve

Answer 23

retinal blood vessels

Question 24

is a complex process that involves a photochemical reaction converting light into electrical impulses.

Answer 24

Vision

Question 25

The _____ is a biconvex transparent structure and is the second refracting unit of the eye.

Answer 25

lens

Question 26

The ________ is a semifluid and transparent structure composed of 99% water with the remnants composed of collagen fiber matrix and mucopolysaccharide (hyaluronic acid). It is normally avascular and does not contain nerves or lymphatics. The vitreous is attached anteriorly to the zonules and to the posterior lens and peripherally at the pars plana and around the optic nerve.

Answer 26

vitreous

Question 27

(the hyaloid vessel system) forms as the lens vesicle and optic cup are forming. The hyaloid artery originates from the site of the future optic nerve and extends to the posterior aspect of the developing lens. This system is compressed centrally and gradually atrophies as the secondary vitreous forms. It has usually disappeared completely by 2-3 weeks of age in the dog but portions may persist for a few months in ruminants.

Answer 27

Primary vitreous

Question 28

is produced by the Muller cells of the retina. As it forms, and the eye enlarges, the primary vitreous becomes proportionally smaller and axially located. The secondary vitreous becomes the adult vitreous.

Answer 28

Secondary vitreous

Question 29

consists of the ciliary zonules (lenticular zonules) suspending the lens. It forms from the neural ectoderm (surface epithelium) of the ciliary body and condenses into the individual zonules.

Answer 29

Tertiary vitreous

Question 30

The is formed by axons of the nerve fiber layer.

Answer 30

optic nerve

Question 31

Myelin develops from the ____ outward to reach the eye a few weeks after birth.

Answer 31

brain

Question 32

myelin usually extends into the eye and a short distance along the nerve fiber layer.

Answer 32

Dog

Question 33

myelin usually does not enter the eye

Answer 33

Cat

Question 34

of the brain extend along the optic nerve to blend into the posterior sclera.

Answer 34

Dura mater and arachnoid

Question 35

The ____’ is the organ that is specialized for hearing and balance.

Answer 35

ear

Question 36

The ear has three parts,

Answer 36

the external ear, the middle ear, and the inner ear.

Question 37

Theexternalearis made of the_________ and the________, which extends to thetympanic membrane(oreardrum).

Answer 37

auricle(orpinna) and external auditory canal

Question 38

Themiddleearis a cavity in the temporal bone and extends from the tympanic membrane to the______in the bony labyrinth.

Answer 38

oval window

Question 39

The middle ear contains three tiny bones or auditory ossicles: ________________________. The function of the middle ear is to amplify incoming sound waves, passing them to the inner ear.

Answer 39

the malleus, incus, and stapes

Question 40

Theinnerearlies in the temporal bone, and it consists of interconnected canals filled with a fluid called__________.

Answer 40

endolymph

Question 41

Thecochleais a spiral canal within the bone that makes three turns around a central bony column called the___________

Answer 41

modiolus

Question 42

The inner ear also houses the__________, which provides the special sense of balance. The vestibular system is comprised of the______________, which indicate rotational movement and aid in orientation, and the_____________, which indicate linear acceleration.

Answer 42

vestibular system
semicircular canals
otolith organs