Ear, nose and throat drugs 

Learning objectives: Learn about the drugs that are instilled or applied on Ear, nose and throat drugs, their classification and mechanism of action.

Parts of the ear

Anatomy of the ear

Anatomy of the Ear

Auditory Canal

The auditory canal is the passage through which sound waves travel after entering the ear.

Visualize the auditory canal as a series of empty cans connected together, symbolizing the pathway of sound.

The canal plays a crucial role in directing sound waves towards the eardrum.

Eardrum (Tympanic Membrane)

The eardrum, also known as the tympanic membrane, vibrates in response to sound waves.

The mnemonic 'drum' helps to remember its function, as drums produce loud sounds that can cause panic.

It serves as a barrier between the outer ear and the middle ear, crucial for sound transmission.

Ossicles: Hammer, Anvil, and Stirrup

The ossicles consist of three tiny bones: Hammer (Malleus), Anvil (Incus), and Stirrup (Stapes).

The order of sound transmission is Hammer → Anvil → Stirrup (H-A-S).

These bones amplify sound vibrations from the eardrum to the inner ear.

Cochlea and Oval Window

The cochlea is a spiral-shaped organ filled with fluid, essential for converting sound vibrations into neural signals.

The oval window is the membrane-covered opening that the stirrup connects to, transmitting vibrations into the cochlea.

Visualize the cochlea as a 'coke' container, where fluid movement is akin to pouring soda.

Basilar Membrane and Cilia

The basilar membrane runs through the cochlea and contains hair cells (cilia) that respond to fluid vibrations.

The mnemonic 'bass swimming' helps to remember the function of the basilar membrane.

Cilia move in response to sound vibrations, playing a critical role in hearing by converting mechanical energy into electrical signals.

[Reference: https://quizlet.com/study-guides/mnemonic-devices-for-eye-and-ear-anatomy-17886793-886d-406e-9988-7e9daf17f7db

Inner ear: https://my.clevelandclinic.org/health/body/24340-inner-ear]

Practice questions

Further reading

• Mnemonic Devices for Eye and Ear Anatomy

• A Brief Overview of Classes of Antibiotics

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References