The document summarizes the anatomy and physiology of the eye and ear. It describes the three layers that make up the eyeball - sclera, choroid, and retina. It details the external structures of the eye including muscles, eyelids, and conjunctiva. It then explains the three main parts of the ear - external, middle, and inner ear. It provides information on the functions and components of each part, such as the ossicles and cochlea.

1. Special
Senses:
The Eye
and Ear
Cassandra Braun

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