Eyes and Ears

Sclera

The outer, white, tough, fibrous protein layer of the eye that provides protection.

Choroid Layer

Consists of capillary beds that supply blood to the photoreceptors in the eye.

Retina

The inner lining of the eye where photoreceptors are located.

Cornea

The clear protein layer at the anterior part of the eye.

Aqueous Humor

A watery fluid found in the anterior chamber of the eye.

Pupil

The opening into the interior of the eye, located in the middle of the iris.

Iris

The colored part of the eye made of smooth muscle that controls the diameter of the pupil.

Lens

Suspended behind the pupil by suspensory ligaments attached to the ciliary body.

Vitreous Humor

A gel-like material in the posterior chamber of the eye.

Fovea

The focal point at the back of the posterior chamber of the eye.

Photoreceptors

Cells in the retina that detect light and translate it into nerve impulses.

Rods

Photoreceptors sensitive to dim light, enabling black and white vision.

Cones

Photoreceptors that provide color vision, most sensitive to red, green, and blue light.

Colorblindness

Inability to see certain colors properly, commonly red-green colorblindness.

Normal Vision

Occurs when light rays converge on the fovea for clear vision.

Myopia

A condition where distant objects appear blurred because the image focuses in front of the retina.

Farsightedness (Hyperopia)

Occurs when the focal point falls behind the retina, resulting in difficulty seeing near objects.

Astigmatism

An irregular curvature of the cornea causing scattered light and blurry vision.

Glaucoma

Condition characterized by high intraocular pressure, which can damage the retina and optic nerve.

Pinna

The outer ear structure that channels sound waves down the ear canal.

Auditory Canal

Conducts sound waves to the tympanic membrane.

Tympanic Membrane

The eardrum that vibrates in response to sound waves.

Ossicles

Three small bones in the middle ear that transmit sound vibrations.

Malleus

Also known as the hammer, it is attached to the tympanic membrane.

Incus

Also known as the anvil, it receives vibrations from the malleus.

Stapes

Also known as the stirrup, it transmits vibrations to the oval window.

Oval Window

An area in the middle ear that separates it from the inner ear.

Eustachian Tube

Connects the middle ear to the pharynx to equalize pressure.

Round Window

Regulates pressure in the ear, located in the wall of the middle ear.

Cochlea

A snail-like structure containing the organ of Corti that translates fluid waves into nerve impulses.

Semicircular Canals

Three canals involved in balance and spatial orientation.

Organ of Corti

Structure in the cochlea responsible for hearing and translating fluid waves into nerve impulses.

Fluid Wave

Created by the push of the stapes on the oval window, moving through the cochlea.

Pitch

Determined by the frequency of the sound wave; higher frequency equals higher pitch.

Volume

Determined by the number of hair cells stimulated in the cochlea.

Dynamic Equilibrium

Controlled by the semicircular canals to maintain balance during movement.

Static Equilibrium

Controlled by the saccule and utricle to maintain balance when still.

Saccule

Part of the inner ear responsible for static equilibrium.

Utricle

Part of the inner ear that helps in maintaining balance.

Sound Waves

Vibrations in the air that are detected by the ear and converted into sound.

Light Refraction

The bending of light as it passes through the eye, primarily by the lens.

Blind Spot

An area on the retina without photoreceptors where the optic nerve forms.