Chapter 15: The Special Senses Flashcards
what is the cornea?
transparent area on anterior surface of the eye
what is the pupil?
opening in center of the iris
function of the pupil
transmits light
what is the conjunctiva?
layer of mucous membrane and epithelium that lines the eyelids and anterior eye
what are the tarsal glands?
modified sebaceous glands
what is the function of tarsal glands?
secretions prevent eyelid from sticking
conjunctivitis is also known as
pinkeye
what is conjunctivitis?
inflammation of the conjunctiva
redness of the eye in conjunctivitis is due to __
dialation of blood vessels deep in epithelium of conjunctiva
what things can cause conjunctivitis?
infection, irritation (physical, chemical, allergic) on conjunctival surface
function of lacrimal gland
makes tears
what is the function of tears?
lubricate, nourish, oxygenate and clean the cornea
lacrimal gland contains ___ and ___ that attack invading pathogens
lysozyme; antibodies
what are the three tunics (layers) of the eye?
- outer fibrous
- middle vascular
- inner
what is contained in the outer layer of the eye?
sclera and cornea
what is contained in the middle layer of the eye?
iris, choroid, ciliary body
what is contained in the inner layer of the eye?
retina
what are the 3 functions of the fibrous layer of the eye?
- support and protect
- attachment site for extrinsic eye muscles
- curve of cornea focuses light
light enters first through the __
cornea
the vascular layer of the eye contains ___, ___ and ___
blood vessels; lymphatic vessels; intrinsic muscles of eye
what are the 4 functions of the vascular layer of the eye?
- route for blood vessels/lymphatic to eye
- regulates amount of light (iris)
- secretes / reabsorbs aqueous humour
- controls shape of lens (ciliary body) = focus
what is the iris/
coloured part of the eye
the iris contains __ and __
blood vessels and pigment cells (melanocytes)
the iris is made of 2 layers of
smooth muscle
what is the role of the smooth muscle in the iris?
contraction changes diameter of pupil to control amount of light entering
what is the ciliary body?
thickened region bulging into interior eye
___ connects ciliary body and lens
ring of fibers
what is the choroid?
vascular layer under the sclera
the choroid has an extensive __ network supplying ___ and __ to the neural layer
capillary network; oxygen/nutrients
function of the outer pigmented layer of the retina
absorbs light
the thick inner neural layer of the retina contains ____
photoreceptors
what are the 2 types of photoreceptors?
rods and cones
eye cavities are separated by ____
lens / ciliary body
the anterior cavity of the eye extends from __ to __
cornea to lens
the anterior cavity contains fluid called __
aqueous humor
the anterior cavity contains 2 chambers ___
- anterior chamber
2. posterior chamber
the anterior chamber of the anterior cavity in the eye extends from the ___ to ___
cornea to iris
the posterior chamber in the anterior cavity of the eye extends from ___ to __
iris to ciliary body and lens
the posterior cavity is filled with gelatinous ___
vitreous body
what is the vitreous humor?
fluid part of the vitreous body
what is the ciliary muscle?
smooth muscle ring that projects into the eye
the aqueous humor circulates within the ___ and passes through the __
anterior cavity; pupil
the aqueous humor is secreted by the epithelial cells of the ____
ciliary processes
the aqueous humor diffuses through the ___ to the ___ surface
vitreous body; retinal surface
the aqueous humor leaves the eye at the ___
scleral venous sinus
the aqueous humor flows into veins in the __
sclera
what are the 4 functions of the aqueous humor?
- transports nutrients and wastes
- forms fluid cushion
- helps retain eye shape
- stabilizes position of the retina
the body of the iris is highly __ pigmented ___ tissue
vascular; loose connective
eye colour is determined by genes that influence ___ and ___
density/distribution of melanocytes; density of pigmented epithelium
T/F the cornea is transparent and clear to allow light through
true
the cornea is a dense matrix of multiple layers of __-
collagen fibers
the cornea is ___ and receives oxygen and nutrients from ___
avascular; tears