Week 1- Overview Flashcards
Equator of the eye is located where
In between the anterior and posterior segments
Globe
Hollow structure that encloses cavity filled with fluid
Located in the orbit (bony cavity or socket)
3 coats (tunics) of the globe
- Outer fibrous layer
- Vascular layer (uvea)
- Inner neural layer
What is in the outer fibrous layer within the top coat (tunic) of the globe
Consists of the cornea and sclera
Sclera
85% of the fibrous portion
Opaque white color
Provides protection for the structures within
Maintains shape of the globe
Covered by episclera, tenons capsule, and conjunctiva
Tenons capsule
Dense connective tissue that protects the epislera/sclera/ eye. Covered by conjunctiva anteriorly.
Cornea
15% of the fibrous portion
Transparent
Allows rays to enter the eye and is the site of refraction. Helps to focus light on the retina. \
Limbus
Location where cornea transitions to conjunctiva/tenon’s capsule/episclera/sclera.
What is included the vascular layer or uvea portion of the 2nd tunic/layer of the globe
Consists of the iris, ciliary body and chorioid
Iris
360 degree
The most anterior layer of the Uvea
Composed of 2 muscles that act as a diaphragm to control the amount of light entering the pupil- iris dilator (contraction dilates the pupil) and iris sphincter (contraction constricts the pupil)
The iris is composed of which 2 muscles
iris dilator (contraction dilates the pupil) and iris sphincter (contraction constricts the pupil)
Ciliary body
The ciliary body is the middle layer of the uvea. It is continuous with the iris and consists of the ciliary muscle and ciliary process.
Ciliary muscle
Apart of the ciliary body, which is continuous with the iris. the ciliary muscle is attached to zones that also attach to the crystalline lens.
The ciliary muscle constricts
How does the lens change shape?
Ciliary muscles contract- Zonules relaxed- lens relaxes and is accommodating. (looking at something up close)
Ciliary muscles relax, zonules under tension, lens is relaxed (looking at something far away)
What power is the cystalline lens capable of?
+20.00D
Humor
body of fluid
Ciliary processes
Produce and secrete aqueous humor
Aqueous humor
Produced by the ciliary processes- travels through the pupil and to between the cornea and iris
Clear fluid that provides nutrition to the lens and surrounding structures in the eye.
Mainly produced from blood.
Choroid
Posterior layer of the uvea
Continuous with the ciliary body
Network of blood vessels that provides nutrition to the outer 1/3 of the retina. Underneath the retina.
Structures within the inner neural layer (which is the third layer or tunic of the globe)
Retina
Macula
Retina
Neural tissue that converts light energy into an electrical signal that can be transmitted to the brain
Most anterior portion of the optic nerve
The optic disc or optic nerve head (what you see on funds photo)
Macula
Small area of the center of the retina responsible for central vision. Contains the fovea, which is located in the center of the macula and provides the highest visual quality due to the dense amount of cones present and no anterior vasculature.
What cranial nerve is the optic nerve
Cranial nerve #2 (sensory)
Interior of the eye is made up of 3 fluid chambers
Anterior chamber - between the cornea and iris/lens
posterior chamber(contains aqueous humor)- between the ciliary body and lens
Vitreous chamber- contains the vitreous humor, between the lens and retina
Anterior and posterior chamber
anterior chamber is located between the cornea and iris/lens.
The posterior chamber is located between the ciliary body and lens.
Each chamber is continuous with the other and contains aqueous humor, which is produced by the ciliary body.
Aqueous humor
Produced by the ciliary process and fills the anterior and posterior chamber. Clear fluid that provides nourishment for the surrounding structures.
Vitreous chamber
Largest chamber in the eye between the lens and retina.
Takes up 80% of the eye in volume
Contains the vitreous humor
Clear, gel like substance that maintains the shape of the eye.
Within the orbit, the eye is surrounded by
Blood vessels, nerves, extra-ocular muscles, connective tissue, fat, and bone.
