C15 - ear1

Question 1

Structures of the external ear?

Answer 1

Auricle/pinna, external auditory meatus, ceruminous glands, tympanic membrane

Question 2

Structures of the middle ear/tympanic cavity?

Answer 2

Auditory ossicles: malleus, incus, stapes.

Muscles: tensor tympani, stapedius

Auditory tube

Middle ear is a small mucosa-lined cavity in the temporal bone.

Question 3

Structures of the internal ear?

Answer 3

Two divisions: Bony labyrinth, membranous labyrinth.

Space between the two is filled with perilymph. Membranous labyrinth is filled with endolymph.

Question 4

Tympanic membrane

Answer 4

Thin CT membrane covered by skin on the outside and mucosa internally. Boundry between outer and middle ear.

Question 5

Malleus/Incus/Stapes

Answer 5

Ossicles. Amplify and Transmit the vibratory motion of the eardrum to the oval window, which in turn sets the fluids of the internal ear into motion.

Question 6

Auricle/pinna

Answer 6

What most ppl consider the ear - external part. Funnel in soundwaves.

Question 7

External auditory meatus

Answer 7

Short tube that extends from the auricle to the tympanic membrane. Contains: Hairs, sebaceous glands, ceruminous glands.

Question 8

Ceruminous glands

Answer 8

Secrete earwax. Repels insect, traps foreign bodies.

Question 9

Tensor tympani/stapedius

Answer 9

Act to decrease movement of the ossicles with very loud sounds

Question 10

What is the hearing receptor?

Answer 10

Spiral organ or corti (collection of hair cells)

Question 11

ossicles

Answer 11

Act as a lever that amplifies the force of vibration and transmits sound waves into the inner ear.

Question 12

Oval window

Answer 12

Stapes footplate meets oval window - transfers vibration into fluids of inner ear (force = 20x more than tympanic mebrane.)

Question 13

Round window

Answer 13

Where pressure dissipates.

Question 14

Bony Labyrinth

Answer 14

System of channels deep in the temporal bone. Filled with perilymph. 3 regions: Vestibule, semicircular canals, cochlea.

Question 15

Membranous labyrinth

Answer 15

Continuous series of membranous sacs and ducts contained within the bony labyrinth, more or less following contours of bony membrane. Filled with endolymph.

Question 16

Perilymph

Answer 16

Between membranous laby and bony laby. Similar to interstitial fluid.

Question 17

Endolymph

Answer 17

Inside membranous laby. Similar to intracellular fluid.

Question 18

What do the two fluids in the labyrinths do?

Answer 18

Conduct sound vibrations involved during hearing and respond to mechanical forces occuring during changes in body position and acceleration.

Question 19

What are the three regions of the bony labyrinth?

Answer 19

Vestibule, semi-circular canals, cochlea

Question 20

Vestibule

Answer 20

Central cavity of bony labyrinth. Contains labyrinth sacs: saccule and utricle.

Question 21

Semi-circular canals

Answer 21

Contain semi-circular ducts: anterior/posterior/lateral. Each duct has a swelling at the end called an ampulla.