16 Special Sense Flashcards
The fluid produced by the ciliary body that fills the anterior and
posterior chambers.
aqueous humor
component of the uvea that extends from the edge of the optic
nerve to the pars plana
choroid
component of the vascular tunic that produces aqueous humor
and is the site of attachment for the ciliary processes and the lenticular
zonules
ciliary body
transparent, avascular structure in the anterior aspect of the eye that
functions to transmit and refract light
cornea
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
iridocorneal angle
anterior most portion of the vascular tunic that functions as a moveable
diaphragm between the anterior and posterior chamber
iris
biconvex transparent crystalline structure that is the second refracting
unit of the eye
lens
component of the nervous tunic of the eye containing photoreceptors
for light
retina
major component of the fibrous tunic in the eyes
sclera
nerve exiting the posterior aspect of the globe that extends to
the rest of the central nervous system
optic nerve
term for the vascular tunic of the eye
uvea
gel like material that fills the vitreous chamber
vitreous humor
gel like material that fills the vitreous chamber
vitreous humor
three tunics from the outside surface of the eye inward
(1) the fibrous tunic (cornea and sclera)
(2) the vascular tunic (iris, ciliary body, and choroid) (3) the neuroectodermal (nervous) tunic
(retina).
composed of the cornea and sclera
fibrous tunic
composed of the iris, ciliary body
and choroid
vascular tunic
composed of the retina
nervous tunic
Inside the eyeball, the lens is suspended in place by? which divides the interior of the eye into two regions, the anterior and posterior cavities
zonular fibers (also called the suspensory ligament)
extends from the posterior surface of the cornea
to the iris
anterior chamber
extends from the iris to the front surface of the
lens
posterior chamber
extends from the posterior surface of the lens to
the retina
vitreous chamber
anterior and posterior chambers are filled with the __________, a watery
fluid similar to plasma
aqueous humor
a transparent, avascular structure that
functions to transmit and
refract light, and as a
protective barrier for the
internal ocular contents
cornea
In general, the cornea of various species is remarkably similar, differing in?
thickness, curvature, shape
corneal epithelium is composed of a what epithelium?
stratified squamous, non-keratinized cell layer
supplies oxygen to
the cornea and approximately 10% of the glucose used by the cornea
tear film
in corneal epithelium, epithelial cells are divided into
basal, wing, and superficial cells
have microvilli, microplicae, and a glycocalyx on their surface to stabilize the tear film
superficial cells
contain abundant glycogen stores and are the
source of cells for the renewal of the outer layers
basal cells
responsible for the secretion of the
basement membrane, this membrane is composed of type IV collagen and
glycosaminoglycans (GAG’s
basal cells
Corneal stroma comprises ____ of the corneal thickness. It is composed of collagen fibers, keratocytes, and GAGs that account for 22%
of the stroma
90%
Corneal stroma comprises ____ of the corneal thickness. It is composed of collagen fibers, keratocytes, and GAGs that account for 22%
of the stroma
90%
remaining 78% of the stroma is?
water
The normal collagen in the corneal stroma is
type I and is more heavily glycosylated than in skin. When injured this is replaced by?
type III collagen
affect hydration, thickness, and transparency
GAGs of stroma
posterior limiting membrane or
Descemet’s membrane is a basal lamina
secreted by?
endothelium
Comprised of type IV collagen and is
produced throughout life, continuing to increase in thickness with age. It is
insoluble except in strong acid or alkali and is more resistant to collagenase
than is the corneal stroma
descemet’s membrane
The innermost layer of the cornea is the endothelium. The origin of this
layer is thought to be?
neural crest cells
constitutes the major portion of the fibrous tunic and joins the
cornea at the limbus
sclera
composed of loose bundles of collagen and elastic fibers, blood vessels, nerves, fibroblasts and, depending on the species and color
pattern, melanocytes
episclera
origin of vascular tunic?
mesoderm
anterior most portion of the vascular tunic and functions as a
moveable diaphragm between the anterior and posterior chambers
iris
shape of pupil in dogs and rabbit?
circular
shape of pupil in horse and owl
oval
shape of pupil in horse and owl
oval
shape of pupil in cats
vertical
normally rest against the anterior lens surface
and in the absence of this support, the iris will tremble
central portion of iris
The color of the iris depends on the pigmentation?
of both the stromal
melanocytes and the posterior epithelium
animals with blue eyes the
pigment is absent in the _______, while in the albino it is lacking in both the
stroma and the posterior epithelium
stroma
homolog of the epithelium of the choroid plexus of the brain. It is a monolayer of hexagonal cells which is continuous anteriorly with the pigmented epithelial layer of the ciliary body and the anterior epithelium of the iris
Retinal Pigmented Epithelium
thickest near the optic nerve and thins towards the periphery
Sensory Retina
rods are long and slender, while the cones tend to have a?
shorter, wider appearance
source of production of the aqueous humor
Ciliary processes
largest part of the vascular tunic, extending from the ciliary body to the optic disc where the optic nerve leaves the eyeball
choroid
made of capillaries and is responsible for the nutrition of the outer parts of the retina
choroid
outermost cells of the sensory retina and is also known as the rod and cone layer.In this layer, a photochemical process takes place to convert light to an electrical impulse occurs in the outer segment.
Photoreceptors (first neuron layer)
less sensitive to light. They provide more detailed vision, color vision and predominant only in the fovea.
Cones
highly sensitive to light. They provide minimal detail and are inactive during daylight vision.
rods
receive input from the photoreceptors and transmit it to the ganglion cells. The nuclei of these cells form the inner nuclear layer.
integrating neurons
receive input from the integrating neurons and transmit impulses to the brain
Ganglion cells (third neuron layer)
supporting cells of the retina, however they do not participate directly in the electrical impulse transmission; lie in the inner nuclear layer among the nuclei of the bipolar neurons
Muller cells
form the nerve fiber layer and converge at the posterior pole of the eye to form the optic nerve
axons of the ganglion cells
complex process that involves a photochemical reaction converting light into electrical impulses.
Vision
acts to reflect light back to the retina and allow more photons to be absorbed by photoreceptors and converted to an electrical potential.
tapetum
biconvex transparent structure and is the second refracting unit of the eye. It lies posterior to the iris and is suspended from the ciliary body by the zonular fibers. It also has a posterior attachment to the anterior vitreous face where it lies in a depression of the vitreous, the patellar fossa.
lens
unique tissue in that it is avascular, transparent, lacks nerve supply, and has the highest concentration of protein in the body.
Lens
Suture lines are in a Y-shape, upright anteriorly and inverted posteriorly,
Human, dogs, and cats
Suture lines are in a Y-shape, upright anteriorly and inverted posteriorly,
Human, dogs, and cats
semifluid and transparent structure composed of 99% water with the remnants composed of collagen fiber matrix and mucopolysaccharide (hyaluronic acid)
Vitreous
forms as the lens vesicle and optic cup are forming.
Primary vitreous
produced by the Muller cells of the retina. As it forms, and the eye enlarges, the primary vitreous becomes proportionally smaller and axially located.
Secondary vitreous
collects sound waves and directs them to the auditory canal; composed of an internal layer of elastic cartilage that is covered by fat and skin.
Auricle
cavity in the temporal bone and extends from the tympanic membrane to theoval windowin the bony labyrinth
Middle ear
The middle ear contains three tiny bones or auditory ossicles:
the malleus, incus, and stapes
amplify incoming sound waves, passing them to the inner ear.
Middle ear
innerearlies in the temporal bone, and it consists of interconnected canals filled with a fluid called
Endolymph
cochleais a spiral canal within the bone that makes three turns around a central bony column called the
Modiolus
receptor cells translate their movement into nerve impulses that travel via the_______to the brain, where they are perceived as sound.
vestibulocochlear nerve (CN VIII)
inner ear also houses the______, which provides the special sense of balance.
Vestibular system
