Chapter 14: Special Senses: Eyes and Ears Review and Biology Flashcards
an-
without, not, absense of
di-
twice, two, double
exo-
away from, outside, external
hemi-
half
hyper-
excessive, above
intra-
in, within, inner
micro-
small
neo-
new
retro-
behind, back
semi-
half
-ar
pertaining to
-cusis
hearing
-edema
swelling
-oid
resembling
-opia
vision, view of
-osis
abnormal condition
-pexy
surgical fixation
-plegia
paralysis
-ptosis
drooping, prolapse
-rrhea
flow, discharge
-rrhexis
rupture
-sclerosis
abnormal condition of hardening
-scope
viewing instrument
-spasm
sudden involuntary contraction
-tomy
cutting into, incision
eyeball
globe-shaped organ that consists of three layers
These are the sclera, the outer portion; the choroid, the middle portion; and the retina, the inner portion.
Each of these layers functions to protect the eye, provide vision, or communicate vision to the brain.
sclera
distinctive white color, provides strength, structure, and shape to the eye
cornea
at front of the eye and bulges forward, is transparent and allows light into the eye.
conjunctiva
thin mucous membrane covers the outer surface of the eye and lines the eyelids; contains many tiny blood vessels and secretory glands
choroid
middle layer of eyeball
a dark-blue vascular layer between the sclera and retina that supplies blood to the entire eye.
also includes the iris, pupil, ciliary body, lens, and suspensory ligaments.
optic nerve
attached to the retina, exits the posterior eye through an opening in the choroid and extends to the brain, where visual messages are delivered.
gathers visual stimuli from the ganglion neurons and transmits this information to the brain for interpretation.
iris
circular structure that surrounds the pupil and gives the eyes their typical color
pupil
functions as an adjustable window that lets light into the inner structures of the eye
ciliary body
ciliary muscles
With the help of ciliary muscles, the lens continually changes shape, enabling us to focus clearly on objects we are viewing.
lens
The lens is a clear, firm, transparent disk.
suspensory ligaments
attaches ciliary muscles to the lens?
accommodation
the lens changing shape to enable us to focus clearly on objects we are viewing.
For near vision, the ciliary muscles contract, causing increased rounding of the lens; for far vision, they expand, causing flattening of the lens
presbyopia
age related decline in visual acuity
retina
It is responsible for the reception of visual impulses through the lens and the transmission of these impulses to the brain
two layers
thin outer red layer due to blood flow from main central artery and contains pigment that protects the choroid and sclera from light at the back of the eye
thick inner layer is visual portion, contains two types of visual receptors called rods and cones
Rods
detect the presence of light and function in dim lighting to produce images in black and white.
Cones
function in more brightly lit situations and detect color
color deficiency
or color blindness
deficiency of cones
Aqueous humor
found in the posterior and anterior chambers. In the anterior chamber, aqueous humor provides nourishment for the lens and cornea.
Schlemm’s canal
where aqueous humor drains through a small opening
vitreous humor
Vitreous humor is a jellylike substance that fills the posterior chamber and gives shape to the eye.
Lacrimal glands
located on the superolateral (upper outer) side of the eye and open through the lacrimal duct at the medial (inner) side, next to the nose. They bathe, moisten, and lubricate the eye by producing tears that flow over the eye’s surface.
Tears
serve a protective role, containing a bacteria-killing enzyme, and wash away foreign debris
ear
responsible for hearing, balance, and equilibrium. The structures of the ear are in three main areas: the external, middle, and internal ear
pinna
The external ear is composed of the auricle, or pinna, which is the outer structure. It is made up of cartilage covered with skin and sits visibly outside of the head.
external auditory canal
a slender tube that leads to the middle ear. The canal is lined with modified sweat glands called ceruminous glands
cerumen
a waxy substance that traps tiny foreign particles and prevents them from entering the ear’s deeper structures.
tympanic membrane (TM)
a thin, flat, irregularly shaped membrane commonly known as the eardrum. It creates a wall between the external and middle ear.
eustachian tube
a downward-sloping canal which connects the middle ear to the throat. It allows air movement between the inner ear and outer atmosphere. When the eustachian tube is closed and the middle-ear pressure is greater or less than atmospheric pressure, we may describe our ears as feeling plugged. The pressure is relieved when the eustachian tube opens to allow air through.
ossicles
(bones)
labyrinth
sometimes another term for the inner ear
cochlea
a tiny, circular, snail-shaped structure filled with fluid
perilymph
fluid in the inner ear
organ of Corti
highly sensitive hearing structure in the inner surface of the cochlea
contains nerve endings called hair cells, which are long, hairlike fibers that transmit impulses to the vestibulocochlear (auditory) nerve.
semicircular canals
located behind the ossicles and two windows, contain perilymph and endolymph, a pale, transparent fluid.
vestibular system
cochlea and semicircular canals
vestibulocochlear (auditory) nerve
nerve impulses that are sent to the brain
Static equilibrium
feeling a sense of balance when we are at rest
dynamic equilibrium
our sense of balance when we are in motion
Endolymph
the pale transparent fluid within the labyrinth, responds to changes in body position based on gravity.
labyrinthitis
Inflammation of the inner ear
