The Ear: Anatomy, function & pharmacology

Learning objectives

Describe the composition, structure and function of the external ear?

Composed of:

• Auricle + External auditory canal

• Auricle = Composed of elastic cartilage covered by skin

• Covered by skin provided w/ annexes including ceruminous glands (modified sweat glands that secrete ear wax). Annexes (skin appendages) are the accessory structures located within the skin lining of the external auditory canal. The Ceruminous glands are a key annex of the ear canal —> located in the deep dermis layer of the outer ear canal secrete ear wax

Function:

• Collect vibrations & waves from the auricle to the tympanic membrane or eardrum

Middle ear: The tympanic membrane

Describe the structure of the middle ear in terms of the tympanic membrane.

• Concave structure: MALLEUS has a handle on the tympanic membrane & it pulls it inward & that keeps it concave

Middle ear: The tympanic membrane

1) What happens when it is illuminated via otoscope?

2) Why is it extremely sensitive to pain?

1) When illuminated via otoscope, the concavity produces a cone of light (a triangle)

2) Innervated from inside & outside