Eye Histology Flashcards
What are the tunics of the eye and their components?
Outer fibrous layer: Sclera, Cornea
Middle Vascular layer: Choroid, Ciliary Body, Iris
Inner Sensory layer: Retina
What is the composition and function of the Sclera?
Dense Connective Tissue
Provides attachment sites for tendons of extraocular muscles
What are three characteristics of the cornea?
Transparent
Avascular*
Many nerve endings
*Complete or partial corneal transplant can be performed
What are the five layers of the cornea?
Corneal epithelium
Bowman’s layer
Stroma
Descemet’s membrane
Endothelium
What is the defining boundary of the Anterior and posterior chambers of the anterior cavity?
The Iris
What lies within the posterior cavity?
Vitreous body
What is the ciliary body and its functions?
Projection of the choroid and retina that includes the ciliary muscle and processes
Functions: Accommodation and production of aqueous humor
How are Ciliary processes connected to the lens?
Suspensory ligaments
Describe accommodation when the ciliaris muscle is relaxed.
The suspensory ligaments become taut - stretching the lens capsule and flattening the lens for distant vision
Describe accommodation when the ciliaris muscle is contracted.
Relaxes the ligaments which allows the lens to bulge for close vision
What is the cause of glaucoma?
Aqueous humor is not reabsorbed at the same rate it is produced, leading to elevated pressure in the eye.
Can cause blindness
What is the function of the iris and what is unique about its composition?
Control the amount of light that enters the eye
The anterior surface has no epithelial cells, but rather a mesh of melanocytes and fibroblasts
What is the function of the lens?
Focus light on the retina.
What are the celllular layers of the lens?
Lens capsule
Lens epithelium - simple cuboidal
Differentiateing lens fibers
Mature lens fibers
What are the characteristics of rod cells?
Monochromatic, used for night vision
Much more numerous than cones
