Special Senses

Allows the human body to react to the environment by providing touch, sight, hearing, taste and smell.

The 1.ORBITS 2. EYE LASHES 3. LACRIMAL glands All provide protection as a function of the eye.*

Conjunctiva- covers eyelid and the front of eye Protects and lubricates eye (this part of the eye is actually a mucous membrane)* Sclera- outer most tough connective tissue Referred to the “white of the eye Retina- When a person looks at an Image, light rays pass through the eye and focus on this.* Cornea-allows light rays to enter the eye “The window of the eye”

Iris- colored part of the eye Controls the size of the pupil Pupil – opening center of iris Lens- Refraction(measurement of the focusing characteristics of an eye or eyes) & Accommodation (the ability of the eye to change its focus from distant to near objects ) * FYI: When you look in a mirror, you see the IRIS, PUPIL, & the SCLERA (not the retina)*

FYI….. When you cry  and your nose runs, the fluid coming out from your nose is TEARS.

Diseases and Abnormal Conditions of the Eye Amblyopia am·bly·opia - “lazy eye” TX: cover good eye to stimulate bad eye, corrective lens or surgery Blindness may occur if not treated before the age of 8-9

Astigmatism Abnormal shape of cornea causing blurred vision TX: Corrective lenses FYI…This condition can occur in someone with a normally shaped eyeball*

Cataracts Normal clear lens becomes cloudy Occurs gradually as a result of aging Blurred vision, halos, or vision loss TX: Surgical removal of the lens then either replaced with an implanted lens or corrective lens to replace for the removed lens

Conjunctivitis “Pink eye” Contagious inflammation of the conjunctiva Caused by bacteria or virus Redness, swelling, pain, and pus formation TX: Antibiotics in ointment form

Glaucoma Increased intraocular pressure caused by an excess of aqueous humor Common after age 4o Leading cause of blindness Loss of peripheral vision, loss of night vision, mild aching TX: Medications to decrease amount of fluid produced or surgery*

Hyperopia- farsightedness Myopia- Nearsightedness Tx: radial keratotomy (RK) is a surgical procedure used to decrease nearsightedness Strabismus (str ə ˈ bizm ə s)- “Cross-eyed” common in children*

How is glaucoma usually treated? Medication Surgical removal of the lens Corrective lenses Radial keratotomy

Effect of aging on the eye Peripheral vision and depth decrease with age Leads to falls and mobility problems

The Ear Controls hearing and balance Transmit impulses from sound waves to auditory nerves that carry to brain for interpretation.

Pinna/auricle- outside of ear (Largest structure of the ear)* Auditory canal- tube traveling down ear that produces ear wax Tympanic Membrane- eardrum ( when a sound is heard, this structure of the ear is 1 st to transmit the sound)* Eustachian tube (yoo-stey-shuh n) - allows air to enter middle ear to allow equalize pressure in the ear Cochlea (kok-lee-uh) - sail shapes, transmits impulses from sound waves External Auditory Canal- may find cerumen here*

FYI….. Your Ossicles (os-i-kuh) transmit sound waves to the inner ear* The ossicles (also called auditory ossicles) are the three smallest bones in the human body

Another FYI…… The Vestibule, Cochlea, & Organ of Corti are all organs of the inner ear involved in hearing… SOOOOOOO that must mean the Semicircular Canals is NOT!!!!***

Diseases and Abnormal Conditions of the Ear Hearing Loss- either conductive or sensory Conductive- when sound waves are not conducted to the inner ear by either a wax plug, inner ear obstruction or infection Sensory- damage to auditory nerve or inner ear

Hearing Loss Conductive-sounds to the ear are blocked by ear wax or fluid in the middle ear Sensory- damage to the inner parts of the ear For Example… If you rupture the tympanic membrane, you will have conductive hearing loss***

Effect of aging on the ear Tympanic membrane becomes fibrotic and unable to transmit sounds

Vertigo Dizziness Loss of balance

Tinnitus Ringing or buzzing heard

Menieres Disease Collection of fluid in the inner ear and a degeneration of the hair cells in the cochlea Severe vertigo, tinnitus, nausea, vomiting, loss of balance TX: drugs that reduce fluid, draining of fluid ▫antihistamines

Otitis Externa Otitis Externa- Inflammation of external auditory canal Caused by pathogenic virus or bacteria Swimmers ear or foreign object TX: Antibiotic

Otitis Media Inflammation or infection of the middle ear caused by bacteria or virus Frequently follows a sore throat Organisms travel from throat through Eustachian tubes to middle ear* TX: Antibiotics

Otosclerosis When stapes of the ear become immobile causing conductive hearing loss Otosclerosis is an abnormal growth of bone near the middle ear. It can result in hearing loss. TX: Surgical removal of the stapes

What disorder could be treated by the surgical insertion of an artificial stapes? Otosclerosis Meniere’s disease Otitis media Sensory hearing loss

Organisms in the throat can travel up the eustachian tube and cause: Otosclerosis. A cerumen plug. Otitis media. Meniere’s disease.

TASTE… influenced by sense of smell

What statement about the sense of taste is true? Taste is influenced by the sense of smell. Taste buds are called lacteals. There are no taste buds in the back of the tongue. There are two main tastes, sweet and salty.

Nose Anatomy

NOSE Olfactory receptors are found here

Disorders of the Nose Rhinitis- inflammation of the lining of the nose May cause nasal congestion Sneezing, itching, and drainage