HESI Eye & Ear

Sclera

Protects the eye

Cornea

Where light rays enter the eye

Aqueous humor

Provides nutrients to the cornea and lens

Iris

Gives eye color & regulates diameter of the pupils to allow light into the eye

Pupils

Regulates amount of light to retina

Choroid

Supplies oxygen & nutrients to the eye

Ciliary body

Secretes aqueous humor & controls size and shape of lens

Vitreous humor

Maintains the shape of the eye & refracts light rays to the retina

Retina

Converts images to visual impulses and sends them to the brain, where they are interpreted

How do light rays from an object get to the retina?

Cornea - aqueous humor - pupil - lens - vitreous humor - retina

Cones

Color vision

Rod

Black & white vision

Fovea

Central part of macula containing only cones & highest visual acuity (sharpness)

Macula

Central part of retina, rich in cones

Lens

Focus & refract light rays from objects

What is found in the bony labyrinth of the ear?

Cochlea, vestibule & semicircular canals

Outer ear

Auricle/pinna

Middle ear

Includes the incus, malleus & stapes (ossicles)

Inner ear

bony & membranous labyrinth and eustachian tube

Utricle

in the vestibule & sensitive to horizontal motion

Saccule

In the vestibule & sensitive to vertical motion

Tympanic membrane

Eardrum, separates outer ear from middle ear & conducts sound to malleus

Eustachian tube

Links the middle ear to the nasopharynx & equalizes ear pressure

Auditory ossicles

Amplify sound waves & send them to the inner ear

Incus (anvil)

Links malleus & stapes

Stapes (stirrup)

Amplifies sound waves, transmits them to the inner ear & links incus & oval window

Organ of Corti

Detects sound waves & generates nerve impulses

Semicircular canals

Sense rotatory motion & function in balancing

Oval window

Transmits sound from ossicles to cochlea

Auricle

Funnels sound waves to external auditory canal

Cristae ampullaris

Found in the semicircular canal

How do sound waves pass?

Auricle - external auditory canal - tympanic membrane - malleus - incus - stapes - oval window - organ of Corti - brain

Cerumen

Ear wax to protect drum