Ch. 4 (ear)

Question 1

External Ear

Answer 1

• pinna cartilage of external ear; directs sounds to ear canal (transduction)
• ear canal
• tympanic membrane

Question 2

Middle Ear

Answer 2

• mallas, incus, stapes; vibrate oval window
• eustachian tube; maintains pressure eg. swallowing (organisms travel from throat, infections, otis media
• oval window vibrates cochlea

Question 3

Inner Ear

Answer 3

1. cochlea; used for hearing
   - round window
2. Vestibular Apparatus; equilibrium and balance
   - cranial nerve eight goes to brain

Question 4

Cochlea

Answer 4

1. Vestibularduct/ Scala vestibuli
   - helicotrema; perliymph= ECF
2. tympanic duct
3. Cochlear duct; endolymph= ICF

Question 5

Organ of Corti

Answer 5

1. Basilar membrane
2. hair cell; kinocilium and sterocilia (sound transduction)
3. tectorial membrane
   * depolarize= pull to tall, repolarize= pull back to small

Question 6

Transduction

Answer 6

1. sound- ear canal- eardrum- mechanical waves
2. 3 ossicles vibrate- shake oval window
3. fluid waves- kinocilium (depolarize)
4. chemical neurotransmitter- action potential
5. cochlea nerve (CN8)- brain

Question 7

Sensorineural Loss

Answer 7

• cochlea
• young and old generations
• hearing aid or cochlear implants
• speech processor and electrodes and transmitter
• due to loud music (continuous depolarize)

Question 8

Central Loss

Answer 8

• destruction of cochlea nerve or higher cortical region

eg. stroke

Question 9

Conductive Loss

Answer 9

• mild/ fixable
• infections and bacteria (children)
• ear wax/ cerumen

Question 10

Measure Sound

Answer 10

• frequency (1000-3000 Hz)
• amplitude (60dB)
• pitch

Question 11

Semicircular Canals (vestibular apparatus) CN3

Answer 11

1. superior canal: head nod (yes)
2. horizontal: head tilt (right or left)
3. posterior head nod (side to side- no)
   - endolymph and ampula (cupula and haircells)
   * * motion sickness: nausea, vomiting- not keeping up with motion

Question 12

Otolith Organs

Answer 12

1. utricle
2. sacelue
   - gelatinous mass + hair cell + otoliths= macula
   - hair cells arranged in a row (linear) eg. tying shoe
   - arranged verticle (up & down movement) eg. elevator

Question 13

Meiner’s Disease

Answer 13

• affects inner ear
• hearing loss (cochlea)
• VanGogh; suffered from nausea, tinnitus, vomiting)
• problems in production or reabsorption of endolymph