Structure of the Eyeball

These flashcards cover key terminology and concepts related to the structure and function of the eyeball.

Fibrous Layer

Outermost layer of the eyeball, composed of dense connective tissue.

Vascular Layer

Middle layer of the eye, also known as the uvea, consisting of the choroid, ciliary body, and iris.

Inner Layer

Innermost layer of the eyeball, includes the retina.

Humors

Fluids that fill the internal cavity of the eyeball.

Conjunctivitis

Inflammation of the conjunctiva, resulting in reddened, irritated eyes.

Pinkeye

A conjunctival infection caused by bacteria or viruses, which is highly contagious.

Lateral Rectus

Extrinsic eye muscle that moves the eye laterally.

Medial Rectus

Extrinsic eye muscle that moves the eye medially.

Superior Rectus

Extrinsic eye muscle that elevates the eye and turns it medially.

Inferior Rectus

Extrinsic eye muscle that depresses the eye and turns it medially.

Inferior Oblique

Extrinsic eye muscle that elevates the eye and turns it laterally.

Superior Oblique

Extrinsic eye muscle that depresses the eye and turns it laterally.

Ciliary Body

Thickened ring of tissue surrounding the lens, consisting of smooth muscle bundles.

Ciliary Processes

Capillaries within the ciliary body that secrete fluid for the anterior segment of the eyeball.

Ciliary Zonule

Also called the suspensory ligament, it holds the lens in position.

Choroid

Posterior portion of the vascular layer, supplying blood to all layers of the eyeball.

Cornea

Transparent anterior part of the fibrous layer that allows light to enter the eye.

Sclera

Opaque posterior region of the fibrous layer that protects and shapes the eyeball.

Optic Disc

Site where the optic nerve leaves the eye, lacking photoreceptors and referred to as the blind spot.

Rods

Photoreceptors in the retina responsible for dim light and peripheral vision.

Cones

Photoreceptors responsible for bright light and high-resolution color vision.

Blind Spot

Area in the retina where there are no photoreceptors, located at the optic disc.

Fovea Centralis

Tiny pit in the center of the macula lutea that contains all cones, providing the sharpest vision.

Macula Lutea

Area at the posterior pole of the retina, mostly containing cones.

Retinal Detachment

Condition where the pigmented and neural layers of the retina separate, which can lead to blindness.

Pupil

Central opening in the iris that regulates the amount of light entering the eye.

Sphincter Pupillae

Circular muscles in the iris that contract to constrict the pupil during close vision.

Dilator Pupillae

Radial muscles in the iris that contract to dilate the pupil during distant vision.

Visual Acuity

The clarity or sharpness of vision, often determined by the activity of cones.

Anterior Segment

Part of the eye in front of the lens, filled with aqueous humor.

Posterior Segment

Part of the eye behind the lens, filled with vitreous humor.

Vitreous Humor

Jellylike substance filling the posterior segment of the eyeball.

Aqueous Humor

Fluid that fills the anterior segment of the eyeball.

Ciliary Muscles

Smooth muscles that control the shape of the lens.

Intrinsically Controllable Muscles

Muscles that allow for the movement of the eyeball.

Accessory Structures of the Eye

Includes extrinsic eye muscles and other components that support eye function.

Homeostatic Imbalance

A medical condition or issue that affects the homeostasis of the eye.

Extrinsic Eye Muscles

Six muscles that originate from the bony orbit and insert on the eyeball.

Neural Layer of Retina

Transparent layer that contains photoreceptors and other neurons essential for processing visual information.

Photoreceptor Cell Fragments

Cell parts that are phagocytized by the pigmented layer of the retina.

Ciliary Zonule Function

Holds the lens in position to enable proper focus of light.

Pigments in Eye

Substances in the choroid that absorb light to prevent scattering.

Tearing Reflex

Involuntary response from corneal pain receptors that causes tearing.

Emotional State Effects

Pupil dilation occurs when a subject is emotionally affected.