The Ear

Question 1

How does the ear form?

Answer 1

Invagination, and formation of pharyngeal pouches.

Question 2

Outer Ear

Answer 2

• Auricle: skin overlaid on elastic cartilage
• Ext. auditory meatus: forms inner canal 2/3, sebaceous/ceruminous glands
• TM: vascularized/innervated tissue

Question 3

Middle Ear

Answer 3

-Auditory vesicles: malleus (TM hammers on), incus, stapes. (attach to oval window)
-Oval window: impedance process
Round window: end of scala-tympani
-Muscles: tensor tympani inset on malleus
–Stapedius: both react to dampen the sound vibrations

Question 4

Inner Ear

Answer 4

Bony Labrynth: High in Na perilymph.

Question 5

Membranous Labrynth

Answer 5

High K endolymph. Embedded into bony labrying

Question 6

Vestibular Organs

Answer 6

Macula of saccule and utricle.

Cristae ampullaris of semicircular canal

Question 7

Maculae of saccule and utricle

Answer 7

• Kinocilium. Use gravity to cause movement of heads, resulting in cell depolarization, relaying feeling of motion.
• Otolithic Membrane: Sensory stimulus with displacement of head movement.

Question 8

Cristae Ampullares

Answer 8

• from semicircular ducts.

- form 3 perpendicular planes

Question 9

Cupula

Answer 9

Gelatinous layer devoid of otoliths.

-shear forces cause the stereocilia to bend with fluid movement.

Question 10

Auditory Organs

Answer 10

Cochlear duct:
scala vestibuli
scala tympani
vestibular membrane
basilar membrane
stria vascularis

Question 11

Organ of Corti

Answer 11

converts soundwaves into our sound perception

Question 12

Spiral Ganglion

Answer 12

Nerve cells that transmit sense of hearing from cochlea to the brain.