1. By: Norma Gongora Chapter 13 Special senses: The Eye and Ear

2. Anatomy and Physiology Relating to the Eye The study of the eye is ophthalmology. The study of the eye is ophthalmology. The eyeball is the incredible organ of sight that transmits an external image by way of the nervous system—the optic nerve—to the brain. The eyeball is the incredible organ of sight that transmits an external image by way of the nervous system—the optic nerve—to the brain. Also included are the eye muscles, eyelids, conjunctiva, and lacrimal glands and ducts. Also included are the eye muscles, eyelids, conjunctiva, and lacrimal glands and ducts.

4. The Eyeball Eyeball is composed of three layers: Sclera Sclera Choroid Choroid Retina Retina

5. Sclera The outer layer, the sclera, provides a tough protective layer for the inner structures of the eye. Another term for the sclera is the white of the eye. The outer layer, the sclera, provides a tough protective layer for the inner structures of the eye. Another term for the sclera is the white of the eye.

6. Cornea The anterior portion of the sclera. The anterior portion of the sclera. Clear, transparent part of the sclera. Clear, transparent part of the sclera. Allows light to enter the interior of the eye. Allows light to enter the interior of the eye.

7. Choroid Second layer or middle layer of the eye. Second layer or middle layer of the eye. This layer provides the blood supply for the eye and is opaque. This layer provides the blood supply for the eye and is opaque.

8. Retina Contains the sensory receptor, rods, and cones. Contains the sensory receptor, rods, and cones. Rods are active in dim light and help us to see in black and white. Rods are active in dim light and help us to see in black and white. Cones are active only in bright light and are responsible for color vision. Cones are active only in bright light and are responsible for color vision.

9. Muscles of the Eye There are six muscles that connect the actual eyeball to the skull. There are six muscles that connect the actual eyeball to the skull. These muscles change the direction each eye is looking in. These muscles change the direction each eye is looking in. They provide support for the eyeball in the eye socket. They provide support for the eyeball in the eye socket.

11. Eyelids Over each eyeball. Over each eyeball. Provide protection from foreign particles, injury from the sun and intense light, and trauma. Provide protection from foreign particles, injury from the sun and intense light, and trauma. Both the upper and lower edges have eyelashes or cilia that protect the eye from foreign particles. Both the upper and lower edges have eyelashes or cilia that protect the eye from foreign particles. Sebaceous glands located in the eyelids secrete a lubricating oil onto the eyeball. Sebaceous glands located in the eyelids secrete a lubricating oil onto the eyeball.

12. Conjunctiva A mucous membrane lining. A mucous membrane lining. Forms a continuous covering on the underside of each eyelid and across the anterior surface of each eyeball. Forms a continuous covering on the underside of each eyelid and across the anterior surface of each eyeball. Serves as a protection for the eye. Serves as a protection for the eye.

13. Lacrimal Gland Located in the outer corner of each eyelid. Located in the outer corner of each eyelid. These glands produce tears. These glands produce tears. Tears serve the important function of washing and lubricating the anterior surface of the eyeball. Tears serve the important function of washing and lubricating the anterior surface of the eyeball. This duct ultimately drains the tears into the nasal cavity. This duct ultimately drains the tears into the nasal cavity.

14. Anatomy & Physiology of the Ear Study of the ear is referred to as otology (Oto). Study of the ear is referred to as otology (Oto). Study of hearing disorders is called audiology. Study of hearing disorders is called audiology. The ear is responsible for two senses: The ear is responsible for two senses: HearingHearing Equilibrium or our sense of balanceEquilibrium or our sense of balance

15. The Ear Subdivided into Three Areas The external ear The external ear The middle ear The middle ear The inner ear The inner ear

17. External Ear The auricle or pinna is the only portion visible; with its earlobe has a unique shape in each person and functions like a funnel to capture sound waves as they go past the outer ear. The auricle or pinna is the only portion visible; with its earlobe has a unique shape in each person and functions like a funnel to capture sound waves as they go past the outer ear. Auditory canal where sound then moves along Auditory canal where sound then moves along Cerumen is produced in oil glands in the auditory canal. Cerumen is produced in oil glands in the auditory canal.

18. The Middle Ear Located in a cavity in the temporal bone of the skull Located in a cavity in the temporal bone of the skull Vital to the hearing process Vital to the hearing process

20. The Inner Ear Located in a cavity within the temporal bone referred to as the labyrinth Located in a cavity within the temporal bone referred to as the labyrinth Contains the hearing and equilibrium sensory organs: Contains the hearing and equilibrium sensory organs: CochleaCochlea Semicircular canalsSemicircular canals UtricleUtricle SacculeSaccule