Chapter 11 Flashcards
blephar/o
eyelid
-cusis
hearing
irid/o
iris
kerat/o
horny, hard, cornea
myring/o
tympanic membrane, eardrum
opthalm/o
eye vision
-opia
vision condition
opt/o
eye vision
ot/o
ear, hearing
phak/o
lens of eye
presby/o
old age
retin/o
retina, net
scler/o
sclera, white of eye, hard
trop/o
turn, change
tympan/o
tympanic membrane, eardrum
adnexa
means the accessory
or adjoining anatomical parts of an organ. The term
adnexa is plural
adnexa of the eye
also known as adnexa oculi, are
the structures outside the eyeball. These include the orbit,
eye muscles, eyelids, eyelashes, conjunctiva, and lacrimal
apparatus
binocular vision
occurs when the muscles of
both eyes work together in coordination to make normal
depth perception possible. Depth perception is the ability
to see things in three dimensions.
canth
corner of the eye
canthus
angle where the upper and lower eye lids meet
cilia
which are small hairs, make up
the eyebrows and eyelashes. Cilia are also present in
the nose to prevent foreign matter from being inhaled.
tarsus
also known as the tarsal
plate, is the framework within the upper and lower
eyelids that provides the necessary stiffness and shape
(tars means edge of the eyelid, and -us is a singular
noun ending) (plural, tarsi). Note: Tarsus also refers to
the seven tarsal bones of the foot’s instep.
tars
edge of eyelid
conjuctiva
is the transparent
mucous membrane that lines the underside of each eyelid
and continues to form a protective covering over the
exposed surface of the eyeball
lacrimal duct
also known as the nasolacrimal
duct, is the passageway that drains excess tears into
the nose.
lacrimal canal
consists of a duct at the inner
corner of each eye. These ducts collect tears and
empty them into the lacrimal sacs. Crying is the overflowing
of tears from the lacrimal canals.
sclera
also known as the white of the
eye, maintains the shape of the eye and protects the
delicate inner layers of tissue. This tough, fibrous tissue
forms the outer layer of the eye, except for the part
covered by the cornea.Note: The combining formscler/o
means the white of the eye, and it also means hard.
choroid
also known as the choroid
coat, is the opaque middle layer of the eyeball that
contains many blood vessels and provides the blood
supply for the entire eye. Opaque means that light
cannot pass through this substance.
retina
the sensitive innermost
layer that lines the posterior segment of the eye. The
retina receives nerve impulses and transmits them to
the brain via the optic nerve. This is also known as the
second cranial nerve
anterior segment
The anterior chamber is located behind the cornea
and in front of the iris. The posterior chamber is
located behind the iris and in front of the ligaments
holding the lens in place. Note: Don’t confuse the
posterior chamber with the posterior segment
aqueous humor
which is also known
as aqueous fluid, fills both of these chambers. The
term aqueous means watery or containing water. As
used here, the term humor describes any clear body
liquid or semifluid substance.
n The aqueous humor helps the eye maintain its
shape and nourishes the intraocular structures. This
fluid is constantly filtered and drained through the
trabecular meshwork and the canal of Schlemm
posterior segment
The posterior segment, which makes up the remaining
two-thirds of the eyeball, is lined with the retina and filled
with vitreous (VIT-ree-us) humor. Also known as vitreous
gel, this is a soft, clear, jelly-like mass that contains
millions of fine fibers. These fibers, which are attached to
the surface of the retina, help the eye maintain its shape
rods and cones of the retina
of the retina receive images that
have passed through the lens of the eye. These images
are converted into nerve impulses and transmitted to
the brain via the optic nerve. Rods are the black and
white receptors, and cones are the color receptors.
macula
also known as the
macula lutea, is the clearly defined light-sensitive area
in the center of the retina that is responsible for sharp
central vision. Note that the term macula means a
small spot. A macula, also known as a macule, can also
refer to a small, discolored spot on the skin, such as a
freckle
fovea centralis
is a
pit in the middle of the macula. Color vision is best in
this area because it contains a high concentration of
cones and no rods.
optic disk
also known as the blind spot, is a
small region in the eye where the nerve endings of the
retina enter the optic nerve. This is called the blind
spot, because it does not contain any rods or cones to
convert images into nerve impulses.
uvea
is the pigmented layer of the eye.
It has a rich blood supply and consists of the choroid,
ciliary body, and iris
ciliary body
which is located within
the choroid, is a set of muscles and suspensory ligaments
that adjust the thickness of the lens to refine the focus of
light rays on the retina (Figure 11.6).
n The ciliary body produces the aqueous humor that fills
the anterior segment of the eye.
n To focus on nearby objects, these muscles adjust the
lens to make it thicker.
n To focus on distant objects, these muscles stretch the
lens so it is thinner.