ANAPHY MT 100 LEC - Special Senses (HEARING)

External (Outer) Ear, Middle Ear, Internal Ear

Enumerate the three major divisions of the Ear

Auricle (Pinna), External Auditory Canal, Tympanic Membrane

Enumerate the parts of the External (outer) Ear

Auricle (Pinna)

collects sound waves, funnels sound toward the external auditory canal

External Auditory Canal

Conducts sound toward the tympanic membrane

External Auditory Canal

Contains ceruminous glands (Cerumen)

Cerumen

a liquid that traps dust, waterproofs the canal, prevents microbial growth

Tympanic Membrane (Eardrum)

vibrates when struck by sound waves, converts sound energy into mechanical vibrations

Middle Ear

an air-filled cavity containing the auditory ossicles

Auditor Ossicles, Oval Window, Auditory (Eustachian) Tube

The Middle Ear consists of:

MALLEUS → INCUS → STAPES

Enumerate the Auditory Ossicles

Auditory Ossicles

amplify sound vibrations, transmit vibrations to the oval window

Stapes

The smallest bone in the human body

Oval Window

Receives vibration from the stapes; marks the entrance into the inner ear

Auditory (Eustachian) Tube

Connects the middle ear to the nasopharynx

Auditory (Eustachian) Tube

equalizes pressure on both sides of the tympanic membrane, opens during swallowing and yawning

Internal Ear

contains receptors for hearing and balance

Cochlea; Vestibule; Semicircular Canals

Enumerate the parts of the Internal Ear

Cochlea

hearing; contains the Organ of Corti

Vestibule

static equilibrium, linear acceleration

Vestibule

Contains the utricle and saccule

Semicircular Canals

dynamic equilibrium, rotational movements

Perilymph, Endolymph

Enumerate the Fluids of the Inner Ear

Perilymph

surrounds membranous labyrinth

Endolymph

inside membranous labyrinth

Hair cells

Movement of the Perilymph and Endolymph stimulates _____