Histology of Ear

Question 1

3 Layers of Ear

Answer 1

1. Outer Ear
2. Middle Ear
3. Inner Ear

Question 2

Outer Ear Components

Answer 2

1. Pinna (Auricle) (lobe)
2. Auditory canal and ceruminous glands (ear wax production)
3. Tympanic Membrane (ear Drum)

Question 3

Pinna is composed of…

Answer 3

Elastic Cartilage and Connective Tissues

Question 4

External Auditory Meatus: Ear Canal is lined by

Answer 4

Epidermis Epithelium

Question 5

Tympanic Membrane: Ear drum (Tympanum) 3 layers

Answer 5

1. External Epidermis
2. Middle fibrous connective tissue
3. Inner simple cuboidal and/or squamous epithelieum

Question 6

Middle Ear Components

Answer 6

Malleus, Incus, Stapes

-pass on vibrations of sound to amplify it

Question 7

Middle Ear Bones Articulate sound- how?

Answer 7

Sound transmitted from ear drum across middle ear via malleus, then incus, then stapes which amplifies sound to cause vibration of the oval window of the inner ear which is connected to the cochlea

Question 8

Bony (bone-like outside) and Membraneous (tissue-like inside) Labyrinth are in…

Answer 8

Inner ear

Question 9

Inner Ear-Sensory Regions

Answer 9

1. Vestibule: Composed of utricle and saccule contain the MACULAE
2. Semicircular canals: at base contain the cristae ampullares
3. Cochlear Ducts: contains the organ of Corti

Question 10

Cochlea/ How sound it transmitted with it

Answer 10

Oval and round window Structures:

Stapes bone transmits movement to the oval window, displacing hair cells on the organ of corti and thus hearing. As the stapes footplate moves into the oval window, the round window membrane moves OUT.

Question 11

What is the Cochlea

Answer 11

Structure that has fluid filled chambers transduce sound wave into a fluid pressure wave

Question 12

Scala Media

Answer 12

Within Coclea:

Contains endolymph secreted by stria vascularis

Question 13

Ototoxicity

Answer 13

property of being toxic to the ear- oxtoxic drugs include antibiotics and chemo

Question 14

Stereocilia Bundles

Answer 14

• Are hair cells connected by side links in the macula and cristae ampullaris
• Under tectorial membrane
• Rub to transduce signal of sound

Question 15

Inner Ear: Sensory Regions

Answer 15

Macula occurs in the utricle and saccule of the vestibule

Question 16

What does the Macula Consist of

Answer 16

Sensory cells that consist of sterocillia and ONE long true cilia embedded in gelatenous layer

Question 17

Utricle and Saccule- Macula- whats it covered with?

Answer 17

Perceive linear acceleration and movement- covered with Otoliths (octoconia) which weight on the gelatinous membrane which causes cilia to bend in response to motion, causing opening of ion channels in the hair ells leading to acitivation

Question 18

Type I and Type II Sensory Hair Cells: Macula

Answer 18

Macula have sterocilia and one true cilia at the end

Question 19

Type I and Type II Sensory Hair Cells: Cristae Ampullares

Answer 19

At base of semicircular canals perceive rotation

-Inertia is provied by rubbing against other side of canals instead of Otoliths