Eye I Flashcards

Question

What are the characteristics of the Lens? What is its function?

Answer 1

Biconvex, transparent and very elastic Avascular No innervation Layers include lens capsule, subscapular epithelium, and lens fibers Function is to focus light rays on the retina

Answer 2

Basement membrane/basal lamina of the subscapular epithelial cells

Answer 3

Cuboidal layer of cells Only present on the anterior surface of the lens Differentiate into lens fibers near the equator of the lens

Answer 4

Subscapular epithelial cells differentiate into lens fibers Near equator of lens Produced throughout life, rate decreases with age Mature fibers lose nuclei and acquire crystallins (lens proteins) Fibers stiffen and enlarge with age

Answer 5

Proteins that increase refractor index of lens fibers

Answer 6

Loss of transparency of the lens

Answer 7

Leads to presbyopia Age related farsightedness related to loss of accomodation

Answer 8

Posterior 5/6 of the eyeball White of the eye Tough fibrous connective tissue (collagen and elastic fibers) Extraocular muscles insert on the sclera Pierced by the optic nerve, blood vessels, and other nerves Function is to maintain the shape of the eyeball

Answer 9

Anterior 1/6 of the eyeball Continuous with the sclera Transparent and avascular Highly innervated Main site of light refraction in the eye Six layers

Answer 10

Junction of cornea and sclera Transition from highly vascularized sclera to avascular cornea Transitions from stratified columnar epithelium to stratified squamous corneal epithelium Trabecular meshwork (Spaces of Fontana) Scleral venous sinus (Canal of Schlemm)

Answer 11

Channels combine to form the scleral venous sinus Drains aqueous humor from anterior chamber

Answer 12

Drains aqueous humor into aqueous veins in sclera Apparatus for outflow of aqueous humor

Answer 13

Aqueous humor produced by ciliary epithelium Secreted into posterior chamber Flows into anterior chamber into the pupil Drains through trabecular meshwork Drains into scleral venous sinus to network of scleral veins

Answer 14

Epithelium Bowman's membrane Stroma Pre-Descemet Layer Descemet's membrane Endothelium

Answer 15

Continuous with bulbar conjunctiva Non-keratinized stratified squamous Cells replaced every 7 days Richly innervated Cells have microvilli to help retain tears and prevent drying

Answer 16

Acellular and does not regenerate Ends at corneoscleral limbus Contributes to strength and stability of cornea Acts as barrier to infection

Answer 17

Most of corneal thickeness - substantia propria Parallel collagen fibrils organized into lamellae Precise orientation of lamellae maintain transparency of cornea Corneal fibroblasts interspersed between lamellae to help with repair process

Answer 18

Protects cornea from damage Thin, tough collagenous membrane Rupture leads to aqueous fluid leaking into cornea

Answer 19

Basal lamina of corneal endothelium Secreted and maintained by corneal endothelial cells Thickens with age Helps maintain corneal curvature

Answer 20

Faces anterior chamber of the eye Simple squamous epithelium Removes excess fluid from corneal stroma to maintain transparency

Answer 21

Muscular diaphragm anterior to the lens Controls size of the pupil and amount of light that contacts retina Melanocytes in stroma and pigment epithelium of iris bock passage of light in the eyes Stroma Pupil

Answer 22

Central aperture of the iris Sphincter pupillae - constricts pupil, innervated by parasympathetics Dilator pupillae - Dilates pupil, sympathetic innervation

Answer 23

Vascularized loose CT Contains melanocytes - determine eye color Sphincter pupillae

Answer 24

2 rows of cuboidal cells Function is to block light rays Posterior row adjacent to posterior chamber Anterior row is myoepithelium Basal surface is dilator pupillae muscle

Answer 25

Ciliary Muscle + Ciliary Processes Ciliary muscle - sphincter muscle, parasympathetic innervation, responsible for accomodation Ciliary processes - zonular fibers (suspensory ligaments), lined with ciliary epithelium that secretes zonular fibers and aqueous humor

Answer 26

Contraction of ciliary muscle relaxes suspensory ligament allowing lens to round for near vision Relaxation of ciliary muscles puts tension on suspensory ligament flattening lens for far vision

Answer 27

Double layer of cuboidal cells Only outer layer pigmented and continuous with the retinal pigment epithelium and nonphotosensitive retina Inner layer is non pigemented and produces aqueous humor and secretes zonular fibers

Answer 28

Between retina and sclera Heavily pigmented and vascularized - absorbs light that has passed through retina and prevents reflection Provides blood to outer layers of retina 2 layers: Choriocapillary layer - inner vascular layer with fenestrated blood vessels, and provides nutrients to outer layers via the opthalamic artery Bruch's membrane - thin hyaline membrane, innermost, attached to first layer of retina

Answer 29

Increase in intraocular pressure due to an increase in volume of aqueous humor - either due to overproduction or impeded drainage Sustained increase in pressure can prevent flow to eye 2 types: Open angle glaucoma - drainage of aqueous humor slowed by blockage of trabecular meshwork , iridocorneal angle is open Closed angle - closing of iridocorneal angle limits or obstructs drainage of aqueous humor

Eye I Flashcards

(53 cards)