Histology and Cell Biology: Visual System

60 flashcards containing key terms and definitions related to histology of the visual system.

Fibrous Tunic

The outer layer of the eye consisting of the sclera and cornea.

Vascular Tunic (Uvea)

The middle layer of the eye, which includes the choroid, ciliary body, and iris.

Neural Tunic

The inner layer of the eye, which consists of the retina.

Cornea

The transparent front part of the eye that covers the iris, pupil, and anterior chamber.

Sclera

The white part of the eye that provides structure and protection.

Aqueous Humor

The clear fluid that fills the anterior chamber of the eye.

Vitreous Body

The gel-like substance filling the space between the lens and the retina.

Ciliary Body

The structure that contains the ciliary muscle and processes, producing aqueous humor.

Iris

The colored part of the eye that controls the size of the pupil.

Pupil

The opening in the center of the iris that allows light to enter the eye.

Retina

The light-sensitive layer at the back of the eye that contains photoreceptors.

Phototransduction

The process by which light is converted into electrical signals in the retina.

Rods

Photoreceptors in the retina responsible for vision in low light conditions.

Cones

Photoreceptors in the retina responsible for color vision and visual acuity.

Macula Lutea

A small yellowish area of the retina that is responsible for central vision.

Fovea Centralis

The central pit in the macula lutea that contains a high concentration of cones.

Optic Nerve

The nerve that transmits visual information from the retina to the brain.

Cataract

Opacification of the lens that can lead to decreased vision.

Glaucoma

A condition characterized by increased intraocular pressure, which can damage the optic nerve.

Retinal Detachment

A condition where the retina separates from the underlying layer, potentially leading to vision loss.

Ciliary Processes

The protrusions of the ciliary body that produce aqueous humor.

Lens

The transparent structure behind the iris that focuses light on the retina.

Corneal Endothelium

The inner layer of the cornea that regulates water content and maintains corneal transparency.

Bowman's Membrane

A thin layer in the cornea that acts as a barrier to infection.

Descemet's Membrane

A thin layer of tissue that serves as a basement membrane for the corneal endothelium.

Corneal Stroma

The thick middle layer of the cornea composed of collagen fibers.

Anterior Chamber

The space in the eye located between the cornea and the iris.

Posterior Chamber

The space in the eye located between the iris and the lens.

Uveoscleral Pathway

A route through which aqueous humor can drain from the eye.

Canal of Schlemm

A channel in the eye that drains aqueous humor from the anterior chamber.

Trabecular Meshwork

A mesh-like structure that facilitates the drainage of aqueous humor.

Icterus

The yellowish discoloration of tissues due to the accumulation of bilirubin.

Anterior Limiting Layer

Another name for Bowman's membrane, a layer of the cornea.

Corneal Epithelium

The outermost layer of the cornea, which protects against injury and infection.

Episclera

The outer layer of the sclera, consisting of loose connective tissue.

Limbus

The border zone between the cornea and sclera.

Hyaloid Canal

A space in the vitreous body that remains after the hyaloid vessels regress.

Macular Degeneration

A condition that results in loss of vision in the center of the visual field.

Vitamin A Deficiency

Can lead to night blindness due to impaired phototransduction.

Retinal Pigment Epithelium (RPE)

A layer of pigmented cells that supports photoreceptors and absorbs scattered light.

Blood-Retina Barrier

A barrier formed by the retinal pigment epithelium that protects retinal cells.

Tarsal Glands

Glands in the eyelid that secrete meibum, which helps to prevent tear evaporation.

Conjunctiva

A transparent membrane covering the eye's surface and the inner eyelids.

Orbicularis Oculi

A muscle that encircles the eye, responsible for closing the eyelids.

Superior Tarsus

A dense connective tissue structure that provides support to the eyelid.

Lacrimal Apparatus

The system that produces and drains tears.

Goblet Cells

Cells in the conjunctiva that secrete mucus to lubricate the eye.

Corneal Erosion

Loss of part of the corneal epithelium, often due to injury or infection.

Retinal Detachment

A separation of the retina from its underlying layer, often requiring surgical intervention.

Ciliary Muscle

Muscle that controls the shape of the lens for focusing.

Aqueous Humor Production

Occurs primarily in the ciliary processes.

Neural Signal Transmission

The process by which light signals are converted to nerve impulses and sent to the brain.