Presentation on theme: "Special Senses Ears Chapter 15. Objectives: O Identify the primary functions of the Ear O Introduce some medical words related to the Ear O Identify and."— Presentation transcript:
Objectives: O Identify the primary functions of the Ear O Introduce some medical words related to the Ear O Identify and define some selected abbreviations related to the Ear
Ear: O One who specializes in the study of hearing is : O Audiologist
Ear: O The ear is the organ that detects soundorgan sound O It also helps provide balance and equilibrium O consists of outer, middle, and inner parts
External (outer) ear: O is the most external portion of the ear O consists of the visible portion on the side of the head, known as the pinna and the external auditory canal or ear canal.
Contd: O Pinna: (also called the auricle) the visible part of the outer ear. It collects sound and directs it into the outer ear canal O External ear canal: the tube through which sound travels to the eardrum. (tympanic membrane)
Contd: O The ear drum is about 1 ¼ inches long O Contains modified sweat glands O Sweat glands secrete Cerumen (Latin word for ear wax) O Too much Cerumen can block sound transmission
Word Building: O Auricle O Aur/iear O -clesmall thing O Pinna O Latin word meaning wing or fin
Contd: O anacusis O an-without, absence of O -acusishearing condition O Total hearing loss O otalgia O ot/ear O -algiapain O Pain in the ear, earache
Middle Ear: O located between the outer ear and the inner ear and consists of the following parts : O Eardrum - The eardrum, also known as tympanic membrane is a thin membrane that acts as a partition between the outer ear and the middle ear. O Has three small bones or ossicles that are important for hearing.
Contd: O Hammer (Malleus) - It is a tiny bone, located next to the eardrum. Since it lies adjacent to the eardrum, the vibrations from the eardrum cause the hammer to vibrate. O Anvil (Incus) - Anvil is another tiny bone next to hammer; it vibrates in response to the vibration of hammer. O Stirrup (Stapes) - Similar to hammer and anvil, stirrup is a tiny bone in the middle ear; eventually, it also vibrates and passes the compressional waves to the inner ear.
Inner Ear: O is the innermost portion of the ear. O It is filled with a water-like substance and comprises both hearing and balancing organs. O Consists of a maze like network of canals located within a bony labyrinth O The bony labyrinth comprises the following parts:
Contd: O Cochlea - or the spiral tube is a rolled structure that can stretch to about 3 cm; O the membrane lining of cochlea consists of numerous nerve cells. The hair-like nerve cells respond differently to various frequencies of vibrations, which ultimately lead to generation of electrical impulses. O Semicircular Canals - These are fluid-filled loops, attached to the cochlea and helps in maintaining the balance. O Auditory Nerve - The electrical impulses, generated by the nerve cells, are then passed to the brain
Process of Hearing: O Outer Ear - captures sound waves and guides them into the ear canal O Ear Canal - carries the sound waves towards the eardrum O Eardrum - (tympanic membrane) vibrates from the sound waves O Middle Ear Bones - (malleus, incus and stapes) pick up vibration from the eardrum O Cochlea - as vibrations pass through this organ, the fluid inside the cochlea moves, causing thousands of "hair cells" to set in motion so they can translate the sound waves into electrical impulses O Auditory Nerve - sends the electrical impulses to the brain to be processed as sound
Common abbreviations: O ACAir conduction O ADRight ear O ASLeft ear O AUBoth ears O BCBone conduction O HDHearing distance O ENTEar, nose and throat O OMOtitis media
Medical Vocabulary: O acoust/hearing O -icpertaining to O Pertaining to the sense of hearing O Acoustic O audi/oto hear O -grama mark, a record O A record of hearing O audiogram
Contd: O equilibrium O Pertaining to the sense of balance O deafness O Complete or partial loss of the ability to hear O tinnitus O The sensation of ringing in one or both ears O vertigo O Sensation of loss of equilibrium
Medical instrument used to examine the eardrum O myring/o O eardrum (TM) O -scope O Instrument for examining O myringoscope
Objectives: O Identify the primary functions of the eye O Introduce Medical words related to the eye O Identify selected abbreviations
Ophthalm/oeye -logystudy of Ophthalmology Study of the eye
O Opthalmologist O opthalm/oeye O -logystudy of O -istone who studies O Physician who specializes in the study of the eye O Optometrist O opt/oeye O metr/measure O -istone who specializes O One who specializes in examing the eye
Eyes: O Most important sense organ O Located in the orbit (bony protective cavity of the skull) O The eye lets light in, focuses it, transforms it into nerve impulses, then sends them to the brain
Contd: O Light passes through the cornea, pupil, lens and the vitreous body to rods and cones ( sensory receptors) in the retina O Vision is made possible by: O the coordinated actions of the nerves that control the eyeball O The amount of light admitted by the pupil O The focusing of light on the retina by the lens O And the transmission of the image to the brain
Parts to the eye: O The eye consists of the inner eye (eye ball) O And the outer eye ( the facial structures and eye muscles surrounding the eye)
External Structures of the eye: O Orbital cavity: bony depression that the eyeballs fits into O Ocular muscles: attach to the sclera and move the eye O Eyelids: shield the eye from light, dust and trauma by blinking O Blephar/oeyelid O Conjunctiva: lines the eyelids and protects and lubricates the eye
Contd: O The eyelids protect the eyes, shade eyes during sleep, and spread lubricating fluid. O The term DACYR/O is used to denote tears. O This lubricating fluid comes from three areas:
Contd: O LACRIMAL GLANDS located above the outer corner of each eye O LACRIMAL DUCTS which drain gland secretions into the lacrimal sacs. O Lacrim/otears O -alpertaining
Internal Structures of the Eye O Eyeball: O Organ of vision O Two cavities: O ocular cavity = space in front of lens has aqueous humor O aque/owatery substance O -ouspertaining to O Posterior cavity = larger cavity has vitreous humor O vitre/otransparent substance O -ouspertaining to
Inner Eye: O Made up of three layers: Outer, Middle and Inner O The outer layer contains: O Cornea: (latin word) is the transparent anterior portion of the eye O Sclera: (scler/o hard) is the white of the eye. Providing a protective covering for the eyeball
Contd: O Middle layer: (uvea)- latin word means grape O Choroids: inner lining of the sclera. Contain blood vessels that nourish the eye O Ciliary muscles: muscles that adjust the shape of the lens for focusing. This produces a watery substance aqueous humor. O cili/ohairlike structure O -arypertaining to
Middle Layer Contd: O The iris is a thin diaphragm composed mostly of connective tissue and smooth muscle fibers. O The opening in the iris is the pupil O The color, texture, and patterns of each person’s iris are as unique as a fingerprint.
Contd: O Inner Layer: O Retina: has layers of nervous tissue called cones and rods O Vitreous humor: jelly like matter in the back of the eye. (80% of eye volume) O This preserves the shape of the eyeball
Contd: O Lens: O A clear flexible disk behind the pupil O Contains protein molecules in a crystalline structure O Function is to sharpen the focus of light on the retina O accommod/oto adapt O -ationa process O accommodation
Process of vision: O Light waves from an object (such as a tree) enter the eye first through the cornea,( the clear dome at the front of the eye) cornea O The light then progresses through the pupil.pupil O Fluctuations in incoming light change the size of the eye’s pupil
Contd: O The light continues through the vitreous humor, vitreous humor O then, ideally, back to a clear focus on the retina, (the retina is equivalent to the film inside of a camera, registering the tiny photos of light interacting with it).retina
Contd: O Within the layers of the retina, light impulses are changed into electrical signals. O Then they are sent through the optic nerve, along the visual pathway, to the occipital cortex at the posterior (back) of the brain. optic nervevisual pathway O Here, the electrical signals are interpreted or “seen” by the brain as a visual image.
Common abbreviations: O ODRight eye O OS Left eye O OUEach eye O PERRLAPupils equal, round, and reactive to light and accommodation O VAVisual acuity O VFVisual field
Contd: O Dirty contact lenses can cause a severe infection called KERATITIS. O Rupture of the cornea is known as KERATORRHEXIS. O The cornea is incised with an instrument known as a KERATOMTOME.