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Warm Up

Warm Up. People with visual problems often use stronger light in order to view small objects. Explain how this is related to the iris. Jot down how the involuntary muscles are used by the eye. . Homework Tues: Lab Report Due Weds: Quiz on Eye and Ear

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Warm Up

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  1. Warm Up • People with visual problems often use stronger light in order to view small objects. Explain how this is related to the iris. • Jot down how the involuntary muscles are used by the eye. • Homework • Tues: Lab Report Due • Weds: Quiz on Eye and Ear • Missed Lab: Make appointment for a Smart Lunch makeup.

  2. Inner Ear • Three key parts • Cochlea • Vestibule • Semicircular canals • Filled with endolymph fluid

  3. Mechanism of Hearing • Cat Scan shows Route of Sound waves through the ear • Amplification • (TM) tympanic membrane • Ossicle Bones • (M)malleus • (In)incus • (St) stapes • (OW) oval window • Cochlea • (SL) spiral lamina • (He) helicotrema • (RW) round window

  4. Vibrate the hairs Hair bundles called “Organ of Corti” Get stimulated as the techtorial membrane vibrates High pitch sounds are closer to the window than low pitch sounds The hair cells transmit along the cochlear nerve When the sound keeps stimulating the receptor it stops responding. Hearing is the last sense to stop when we sleep or die.

  5. Route that sounds travel

  6. Equilibrium • Humans sense movement and direction of movement . • From an early age: Infant is tilted backwards, its eyes will move downward so its gaze can remain fixed. • Hard to describe because it is not a hear, see or feel although these are integrated into our sense of space.

  7. Equilibrium • Responds to two kinds of motion • Static: position of head in response to linear motion of the body. (Starting to walk, stopping) • Dynamic: position of head in response to rotational motion (Rocking, turning etc.) • Signals are integrated to establish equilibrium. Other senses are also incorporated. • Eyes: Horizon, relative position • Ears: Sound establishes position

  8. Static Equilibrium: Vestibule Otolithic membrane: Contains Otoliths: tiny stones made of Ca Salts Hairs bend – sends impulse along vestibular nerve Which way is UP.

  9. Dynamic Equilibrium: Semicircular Canals Each canal about ½ inch around Orientated in 3 different planes As head rotates, one or more canal detects movement. When moving at a constant rate the signal ceases. Within each canal a gelatin Cap containing hairs. The endolymph fluid moves in the canal and pushes the cap. Signal detected by hair which Transmits along the vestibular nerve

  10. Ear Problems: Mechanical Problemsor Conduction Loss • Deafness is defined as a hearing loss of any degree. • Build-up of Ear Wax • Fusion of the ossicles bones (otosclerosis) • Ruptured ear drum • Otitis media • Ear Ache • Often Corrected with a hearing aid

  11. Ear Damage: Sensorineural Deafnessor Nervous system loss • Damage or degeneration of Organ of Corti, cochlear nerve damage or neurons in the auditory cortex. • Damaged or broken hairs • Listening to loud sounds • Test: • If you can hear through the bone, it is conduction loss.

  12. Equilibrium Problems • Symptoms • Nausea • Dizziness • Problems maintaining balance • Often comes when sensory inputs disagrees.

  13. Ménière’s syndrome • Serious ear failure between ages 30 - 60 • Symptoms • Vertigo • Hearing Loss • Tinnitus • Sensation of ear pressure • Cause • Too much endolymphic fluid • Herpes suspected • Arteriosclerosis

  14. Eye and Ear worksheets

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