Module 13: Eye and Ear
- 2. OPTHALMOLOGY: The study of the eye FUNCTION: The eye provides vision through sensory receptor cells The Eye
- 3. Anatomy and Physiology of the Eye Eyeball: composed of three layers Sclera Choroid Retina External Structures: Eye muscles Eyelids Conjunctiva Lacrimal apparatus
- 4. The Sclera (white of the eye) is the outer most layer of the eye Function: tough protective coating for inner structures Cornea: anterior area of the sclera that allows light to enter the interior of the eyeball. - the cornea refracts light rays The Eyeball: Sclera
- 5. The Choroid is the middle layer of the eyeball Function: opaque layer providing blood supply to the eye Contains: Iris: colored portion of the eye containing smooth muscle Pupil: opening in the center of the iris that allows light rays to enter Cillary Body: connected to the lens, changes the shape of the lens to focus incoming light on the retina The Eyeball: Choroid
- 6. The retina is the innermost layer of the eyeball Function: responds to light rays through cones and rods Contains: Rods: active in dim light; help us to see grey tones Cones: active only in bright light; responsible for color vision Macula lutea: when looking at an object, image falls on this area Fovea centralis: central area of macula lutea Optic Disk: point where retinal blood vessels enter and exit the eyeball and where the optic nerve leaves the eyeball Aqueous tumor: liquid that fills the space between the cornea and lens Vitreous humor: semisolid gel in the large, open area between the lens and the retina The Eyeball: Retina
- 7. Function: Six muscles connect the eyeball to the skull – allow for change in direction of each eye and support Four rectus muscles are straight, pulling the eye up, down, left, right or straight. Two oblique muscles are on an angle, producing diagonal eye movement Muscles of the Eye
- 8. Function: provides protection from foreign particles Eyelashes (cilia): protect the eye from foreign particles Sebaceous glands: located in the eyelids secrete lubricating oil onto the eyeball The Eyelids
- 9. The conjunctiva is a mucous membrane lining Function: serves as a protection for the eye by sealing off the eyeball in the socket Conjunctiva
- 10. Lacrimal gland is located under the outer upper corner of each eyelid; produces tears Lacrimal ducts inner corner of the eye socket collects tears and drain them into the nasolacrimal duct, which ultimate drains into the nasal cavity. Lacrimal Apparatus
- 11. Vision: How We See
- 12. OTOLOGY: the study of the ear FUNCTION: the ear provides hearing and equilibrium from sensory receptors The Ear
- 13. The ear contains three main components: External Ear Middle Ear Inner Ear Anatomy and Physiology of the Ear
- 14. External Ear contains three sections: auricle, auditory canal, and tympanic membrane Auricle (pinna): only visible portion, acts like a funnel to capture sound waves and channel them to the external auditory meatus Auditory canal: sound moves across and causes the tympanic membrane External Ear
- 15. Middle Ear contains the auditory tube, Eustachian tube, incus, malleus, ossicles, oval window, stapes Ossicles are the air-filled cavity that contain the three ear bones: malleus, incus, and stapes- these bones amplify the vibrations in the middle ear and transmit them to the inner ear Oval window is the very thin membrane that covers the opening to the inner ear Eustachian tube connects the nasopharynx with the middle ear and opens each time you swallow- the connection allows pressure to equalize Middle Ear
- 16. Inner Ear contains the cochlea, labyrinth, organs of Corti, saccule, semicircular canals, and the utricle Labyrinth is the fluid filled cavity which contains hearing organs (cochlea) and equilibrium organs (semicircular canals, utricle, saccule) Organs of Corti: the hair cells in the cochlea Inner Ear
- 17. How We Hear