Eye Flashcards
The tough fibrous connective tissue in the socket suspended in the bony orbit
Bulbar fascial sheath
What is the retrobulbar fat
takes up the space around the eyeball and acts as a cushion - prevents posterior displacement of the eyeball by the muscles - degrades as we age (“sunken” in look in the elderly)
what are the components of the lacrimal apparatus?
- Lacrimal gland
- Lacrimal caruncle
- Lacrimal drainage
What is the function of the lacrimal gland?
produces lacrimal fluid (tears) and releases it to moisten the eye when we blink
What is the lacrimal caruncle?
bulbous tissue in the medial portion of the eye that contains oil and sweat glands
Very vascular
“Lacrimal lake”
What is the lacrimal lake?
The place where tears collect
What is the function of lacrimal puncta?
Drain fluid from the eye
What do the lacrimal puncta drain into?
lacrimal canaliculi
What do the lacrimal canaliculi drain into?
lacrimal sac
Where is the lacrimal sac located?
in the lacrimal canal
What does the lacrimal sac drain into?
nasolacrimal duct found under the inferior nasal concha
How large is the eye?
~25mm in diameter
True or false: the eye is a peripheral organ
FALSE!! it is in fact an extension of the brain!
List the layers of the eyeball
Tunica fibrosa” outer layer (AKA sclera)
tunica vasculosa
Tunica nervosa
The tunica fibrosa is an extension of the brain’s ______ _________
dura mater
What do the parallel fibers of the tunica fibrosa form on the anterior aspect of the eye?
transparent cornea
what is the major focuser of light?
cornea (lens does fine-tuning)
What is the iris?
the pigmented portion of the tunica fibrosa that is not covered by the cornea
True or false: the cornea is vascular and has little innervation
False (some veins; extremely innervated (esp. the cornea))
What is the darkest layer of the eye?
tunica vasculosa
What are the portions of the tunica vasculosa?
- coroid (most of it) turns into the
- ciliary body
- iris
What is the function of the ciliary body?
ring of muscle that suspends the lens
What are zonules?
Connected to the lens making it spherical and helps the lens to focus light (visual accommodation)
When using far vision, what is the ciliary body doing?
it is relaxed making the ring of muscle larger in diameter so suspensatory ligaments pull the lens tight
When using near vision, what is the ciliary body doing?
it is flexed causing the ring of muscles to be smaller in diameter so the suspensatory ligaments slack and relax the lens (goes back into a spherical shape)
What is the ora serrata?
posterior edge of ciliary body that is scalloped
What is the iris?
colored part of the eye
changes the shaped of the pupil
What are the 2 muscle groups of the iris?
- pupillary sphincter: rounded muscle group closest tot he pupil causing constriction- - works much faster than the dilator
- pupillary dilator: outer ring of muscles that pull away from the pupil
What is the tunica nervosa?
Retina - comes from the brain and lines the inside of the eyeball
What are the two layers of the tunica nervosa?
Neural portion: photoreceptors
Pigmented portion: found behind the neural layer - made up of pigmented (melanin) simple epithelium - reduces the amount of light scatter
What is the fundus?
the posterior portion of the eye
What can you see when performing a fundus exam?
the retina
Where are the optic disc and nerve located?
in the back of the retina
What is the macula?
The dark region in the center of the eye with a heavy concentration of light receptors (cones) - area with the highest visual acuity
What is the fovea?
located in the very center of the macula - high high high concentration of cones and visual acuity
What can be observed with retina vessels?
their condition mimics the characteristics of vessels throughout the body (can show HTN or diabetes)
What are the three chambers of the eye?
Anterior chamber
Posterior chamber
Vitreous chamber
Describe the anterior chamber of the eye
- Between cornea and iris
- Filled with aqueous humor which helps to maintain pressure in the anterior chamber
What absorbs aqueous humor from the anterior chamber of the eye and where does it go?
trabecular network - drains it into the canal of Schlemm
Where does the canal of Schlemm drain aqueous humor to?
small venules of the sclera
High pressure of aqueous humor can lead to _______
glaucoma
Define pigment dispersion syndrom
Pigment of the iris flakes off and plugs up the drainage system - can lead to glaucoma
describe the posterior chamber of the eye
- between the iris and the lens/ciliary body
- produces aqueous humor which flows through the pupil to the anterior chamber
Where is aqueous humor produced?
in the posterior chamber in the ciliary processes (outgrowths of the ciliary body)
Describe the vitreous chamber of the eye
- posterior segment of the eyeball
- contains vitreous body
- holds the retina in place
What is the vitreous body?
gelatinous substance that contains collagen fibers making it a spherical gelatinous mass - gives the eyeball its shape
What can happen to the vitreous body as you age?
The collagen fibers can break down and clump together which can pull away from the retina causing a detached retina
What covers the inside of your eyelids?
palpebral conjunctiva ( reflected onto the eyeball where it is continuous with the bulbar conjunctiva of the eye)
What does the bulbar conjunctiva contain?
vessels on the outside of the sclera
What are the superior and inferior conjunctival fornices?
lines of reflection of the palpebral cinjunctiva that form deep recesses
what allows that eyelids to move freely over the surface of the eye?
cinjunctival sac
What forms the skeleton of the eyelids and strengthens them?
Superior and inferior tarsi
What are ciliary glands?
sebaceous glands associated with the eyelashes
Compare/contrast the lateral and medial palpebral ligaments
Medial: between the nose and the medial angle of the eye - provides insertion for the orbicularis oculi
Lateral: on the later aspect of the eye - no muscle insertion
what keeps orbital fat contained and can limit the spread of infection to and from the orbit?
orbital septum
