9.3 Ear and auditory tube

Question 1

Describe the structures of the outer ear?

Answer 1

Auricle, External acoustic meatus, Cerumen glands, Tympanic membrane

Question 2

Desribe the Auricle

Answer 2

Collects sound, supported by cartilage

Question 3

Describe the External acoustic meatus

Answer 3

Supported by cartilage for lateral 1/3, bone medial 2/3. Innervated by Vagus posteroinferiorly and Auriculotemporal nerve anterosuperior

Question 4

What are the structures of the middle ear?

Answer 4

Epitympanic recess, Tympanic cavity proper, Auditory tube, Mastoid air cells

Question 5

Describe Epitympanic recess

Answer 5

Above the tympanic membrane and communicates with mastoid hair cells

Question 6

Describe the Auditory tube

Answer 6

Protects anterinferiorly to nasopharynx

Question 7

Describe the location of the Tympanic cavity proper

Answer 7

It is medial to the tympanic membrane

Question 8

What are the ossicles?

Answer 8

Malleus, Incus and Stapes

Question 9

What is different between adult and infant eustachian tubes?

Answer 9

In infants, the eustachian tube is more horizontal making it easier for bacteria to move into the middle ear leading to increased infections

Question 10

What is the Stapedius?

Answer 10

Posterior, Innervated by CN 12, muscle that attaches to Stapes

Question 11

What is the Tensor Tympani?

Answer 11

Anterior, Inervated by CN 5, muscle that attaches to malleus

Question 12

What is a reflex mechanism between Stapedius and Tensor Tympani

Answer 12

When there is a loud noise they can contract, pulling on the ossicles making them not vibrate as much, thus dampening the sound

Question 13

What is the Chorda tympani?

Answer 13

Nerve branch from the facial nerve that goes down into the tongue

Question 14

Name the structures of the Inner ear

Answer 14

Oval window, Petrous part of temporal bone, Bony labyrinth, Membranous labyrinth, Round window

Question 15

Describe the bony labyrinth

Answer 15

Space in bone filled with perilymph, consists of the Semicircular canals, Vestibule, Cochlea, Oval window, Round window

Question 16

Describe the membranous labyrinth

Answer 16

Closed sac frilled with endolymph, Cochlear duct (sensory receptors for hearing), Cochlear nerve, vestibular nerve, saccule, utricle, ampulla and semicircular ducts

Question 17

What are the 3 semicircular ducts?

Answer 17

Anterior, Horizontal and Posterior

Question 18

What is the Ampulla?

Answer 18

Swelling that gives info about the head movement

Question 19

High frequency sound is registered where in the Cochlea?

Answer 19

At the base

Question 20

Low frequency sound is registered where in the Cochlea?

Answer 20

At the apex

Question 21

What is a brief physiological understanding of hearing?

Answer 21

That the vibration of the basilar membrane results in movement of hair cells against the tectorial membrane sending signals to the nerve and then to the brain

Question 22

What is dynamic equilibrium?

Answer 22

Movement of endolymph through semicircular ducts in Ampulla deflecting cupula and activating hair cells

Question 23

What is static equilibrium?

Answer 23

Movement of otolithic membrane due to gravity activates hair cells in utricle and saccule