WARM UP 4/24

What does each do?What does each do?1.1. MedullaMedulla2.2. Olfactory cellOlfactory cell3.3. ConesCones4.4. Temporal lobeTemporal lobe5.5. Pituitary glandPituitary gland6.6. Vestibulocochlear nerveVestibulocochlear nerve7.7. Taste budTaste bud8.8. Hypoglossal nerveHypoglossal nerve9.9. RetinaRetina

NOTES CH 11 4/24

The earThe ear

AUDIOLOGY

The study of the earThe study of the ear

The ear consists of 3 parts:

1.1. OuterOuter

2.2. MiddleMiddle

3.3. InnerInner

OUTER EAR

PINNA – part you seePINNA – part you see EXTERNAL AUDITORY CANALEXTERNAL AUDITORY CANAL CERUMINOUS GLANDS – produce wax CERUMINOUS GLANDS – produce wax

to protect the earto protect the ear TYMPANIC MEMBRANE (eardrum)TYMPANIC MEMBRANE (eardrum)

MIDDLE EAR EUSTACHIAN TUBE EUSTACHIAN TUBE

– links the ear to the – links the ear to the throat. Purpose is to throat. Purpose is to equalize pressure in the equalize pressure in the ear.ear.

Normally flat – unequal Normally flat – unequal pressure, EX: yawning pressure, EX: yawning or high altitudes – opens or high altitudes – opens up and hear a “popping” up and hear a “popping” soundsound

Tube more Tube more horizontal when horizontal when younger – reason younger – reason to never give baby to never give baby bottle on back.bottle on back.

Milk can go into the Milk can go into the ears and cause ears and cause infection/ earacheinfection/ earache

OTITIS MEDIA – OTITIS MEDIA – ear infection. ear infection.

3 SMALLEST BONES3 SMALLEST BONES

HAMMER, ANVIL, STIRRUPHAMMER, ANVIL, STIRRUP

(malleus, incus, stapes)(malleus, incus, stapes)

These transmit vibration of the eardrum to the These transmit vibration of the eardrum to the inner earinner ear

INNER EAR

COCHLEA – snail like area filled with COCHLEA – snail like area filled with fluid where auditory cells and hairs are fluid where auditory cells and hairs are locatedlocated

SEMICIRCULAR CANALS – 3 tubes SEMICIRCULAR CANALS – 3 tubes where fluid located; helps with equilibriumwhere fluid located; helps with equilibrium

EQUILIBRIUM

1.1. STATIC – detect up and down movement of STATIC – detect up and down movement of head. (Tiny calcium stones in fluid hitting head. (Tiny calcium stones in fluid hitting against hairs when move)against hairs when move)

2.2. DYNAMIC – detects angles and whole body DYNAMIC – detects angles and whole body movement (Fluid moves in semicir canals)movement (Fluid moves in semicir canals)

Both messages are sent to the cerebellumBoth messages are sent to the cerebellum

Why still feel movement when stop?The fluid is still moving in the ears and The fluid is still moving in the ears and

sending message to brain that you are still sending message to brain that you are still moving.moving.

Why nausea? Eyes give message not moving, Why nausea? Eyes give message not moving, ears give message you are – conflict in the ears give message you are – conflict in the brain brain

Constant sound or constant movement (like in Constant sound or constant movement (like in a car) – your body adapts and soon ignores a car) – your body adapts and soon ignores it so you don’t notice it any moreit so you don’t notice it any more

DEAFNESS

1. CONDUCTION – vibration being stopped1. CONDUCTION – vibration being stopped

2. SENSORINEURAL – damage to receptor 2. SENSORINEURAL – damage to receptor cells (hairs), nerve or temporal lobe of cells (hairs), nerve or temporal lobe of brainbrain

Facts About Hearing Loss •More than 40 million Americans have hearing loss.

•Approximately 40% of the hearing-impaired are under age 65.

•About 2 million children under age 18 are hearing-impaired in the U.S.

•Minor decreases in hearing, especially of higher frequencies, are normal after age 20.

•Some form of hearing loss affects 1 out of 5 people by age 55.

•Hearing loss is the third leading chronic disability, following arthritis and high blood pressure.

•Between 7 and 10 million people in American industry have noise-induced hearing loss, virtually all of which was preventable.

•About 15% of college graduates have a level of hearing loss equal to or greater than their parents; a significant cause is listening to loud music.

•In the U.S., 12 million people have hearing aids.

EAR LABELING

1.1. PinnaPinna

2.2. External auditory External auditory canalcanal

3.3. Tympanic membraneTympanic membrane

4.4. StirrupStirrup

5.5. Eustachian tubeEustachian tube

6.6. SKIPSKIP

7.7. cochleacochlea

8.8. Vestibulocochlear Vestibulocochlear nervenerve

9.9. Semicircular canalSemicircular canal

10.10. AnvilAnvil

11.11. HammerHammer

HEARING PHYSIOLOGY

1.1. SoundSound

2.2. Through auditory canalThrough auditory canal

3.3. Tympanic membrane vibratesTympanic membrane vibrates

4.4. Hits hammerHits hammer

5.5. Hits anvilHits anvil

6.6. Hits stirrupHits stirrup

7.7. Presses on outside of cochleaPresses on outside of cochlea

8.8. Fluid movesFluid moves

9.9. Hairs bend (action potential starts)Hairs bend (action potential starts)

(# of cells stimulated determines (# of cells stimulated determines loudness)loudness)

8.8. Message through vestibulocochlear nerveMessage through vestibulocochlear nerve

9.9. Brain interprets at the temporal lobe of Brain interprets at the temporal lobe of cerebrumcerebrum