Anatomy of the Human Ear

Study Notes

Pinna (Auricle): visible, cartilaginous structure that collects sound waves
External Auditory Canal (EAC): narrow tube connecting pinna to eardrum
Eardrum (Tympanic Membrane): thin, flexible membrane that vibrates with sound waves
External Auditory Meatus: opening of the EAC to the outside environment

Eardrum (Tympanic Membrane): vibrates with sound waves, transmitting them to ossicles
Ossicles: three small bones that amplify sound vibrations
- Malleus (Hammer)
- Incus (Anvil)
- Stapes (Stirrup)
Middle Ear Cavity: air-filled space containing ossicles and eardrum
Eustachian Tube: connects middle ear to back of throat, regulating air pressure

Cochlea: spiral-shaped structure responsible for sound processing
Basilar Membrane: membrane running along the cochlea, vibrating with sound waves
Hair Cells: sensory cells embedded in basilar membrane, converting vibrations to electrical signals
Auditory Nerve: carries electrical signals from hair cells to the brain for sound interpretation
Spiral Ganglion: collection of nerve cells that transmit sound information to the brain

The pinna, a visible, cartilaginous structure, collects sound waves.
The external auditory canal (EAC) is a narrow tube that connects the pinna to the eardrum.
The eardrum, a thin, flexible membrane, vibrates with sound waves.
The external auditory meatus is the opening of the EAC to the outside environment.

The eardrum vibrates with sound waves, transmitting them to the ossicles.
The three small bones that amplify sound vibrations are the malleus (hammer), incus (anvil), and stapes (stirrup).
The middle ear cavity is an air-filled space containing the ossicles and eardrum.
The Eustachian tube connects the middle ear to the back of the throat, regulating air pressure.

The cochlea is a spiral-shaped structure responsible for sound processing.
The basilar membrane, a membrane running along the cochlea, vibrates with sound waves.
Hair cells, sensory cells embedded in the basilar membrane, convert vibrations to electrical signals.
The auditory nerve carries electrical signals from hair cells to the brain for sound interpretation.
The spiral ganglion is a collection of nerve cells that transmit sound information to the brain.

The middle ear is an air-filled cavity that plays a crucial role in sound conduction and transmission.
Its primary function is to amplify sound vibrations by 20-30 times, allowing the eardrum to vibrate more efficiently.
It transduces sound energy, converting sound vibrations into mechanical energy, which is then transmitted to the inner ear.

The eardrum (tympanic membrane) is a thin, transparent membrane that separates the outer ear from the middle ear.
Ossicles (malleus, incus, and stapes) are three small bones that transmit sound vibrations from the eardrum to the inner ear.
The malleus (hammer) is attached to the eardrum and transmits vibrations to the incus.
The incus (anvil) transmits vibrations from the malleus to the stapes.
The stapes (stirrup) transmits vibrations from the incus to the inner ear through the oval window.

Sound conduction occurs when sound vibrations from the eardrum cause the ossicles to vibrate, transmitting these vibrations to the inner ear.
The acoustic reflex is a protective mechanism that helps regulate loud sounds by reducing the amplitude of vibrations transmitted to the inner ear.