Chapter 17 Sense Organs

Accommodation

The normal adjustment of the eye to focus on objects from far to near.

Anterior Chamber

The space behind the cornea and in front of the lens and iris, containing aqueous humor.

Aqueous Humor

Fluid produced by the ciliary body, found in the anterior chamber of the eye.

Biconvex

Describing a shape with two rounded, elevated, and evenly curved surfaces.

Choroid

The middle layer of the eye, containing blood vessels, located between the retina and the sclera.

Ciliary Body

The structure surrounding the lens that connects the iris to the choroid and contains ciliary muscles.

Cone

Type of photoreceptor in the retina responsible for color vision and central vision.

Conjunctiva

The thin, transparent membrane lining the inside of the eyelids.

Cornea

A transparent, fibrous layer of tissue that covers the front of the eye.

Fovea Centralis

A small depression in the retina responsible for sharp central vision.

Fundus of the Eye

The posterior, inner part of the eye visible through an ophthalmoscope.

Iris

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

Lens

A transparent, biconvex structure located behind the pupil that helps focus light.

Macula

The area near the optic disc that contains the fovea centralis.

Optic Chiasm

The point in the brain where optic nerve fibers from both eyes cross.

Optic Disc

The region at the back of the eye where the optic nerve meets the retina.

Optic Nerve

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

Pupil

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

Refraction

The bending of light rays as they pass through the eye structures.

Retina

The light-sensitive layer at the back of the eye containing photoreceptor cells.

Rod

A photoreceptor cell in the retina essential for low light vision.

Sclera

The tough, white outer layer of the eyeball, providing structure and protection.

Thalamus

The relay center in the brain for processing visual information.

Vitreous Humor

A jelly-like substance located behind the lens in the vitreous chamber.

Astigmatism

Defective curvature of the cornea or lens causing distorted images.

Hyperopia

Farsightedness where light rays focus behind the retina.

Myopia

Nearsightedness where light rays focus in front of the retina.

Presbyopia

Impairment of vision due to aging's loss of lens elasticity.

Cataract

Clouding of the lens causing blurry vision.

Chalazion

A small, hard bump on the eyelid caused by a blocked gland.

Diabetic Retinopathy

Damage to the retina from diabetes leading to blurred vision.

Glaucoma

Increased pressure in the eye damaging the optic nerve.

Macular Degeneration

Loss of central vision while peripheral vision remains normal.

Nystagmus

Rhythmic, uncontrollable eye movements.

Retinal Detachment

Separation of the retina from the eye causing flashes of light.

Strabismus

Misalignment of the eyes causing one eye to turn.

Fluorescein Angiography

A test to take pictures of the retina to check blood flow.

Ophthalmoscopy

Examination of the eye using a special light and tool.

Visual Acuity Test

A test to check how well you can see using a chart.