Key Notes:

🔹 Overview

• The human ear is the organ of hearing and balance.
• It has three main parts: Outer Ear, Middle Ear, and Inner Ear.

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1️⃣ Outer Ear

Parts:

• Pinna (Auricle): Collects sound waves.
• Auditory canal (Ear canal): Carries sound to the eardrum.

Function:

• Collects and directs sound waves toward the eardrum.

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2️⃣ Middle Ear

Parts:

Eardrum (Tympanic membrane): Vibrates when sound waves strike it.

Three tiny bones (Ossicles):

• Malleus (Hammer)
• Incus (Anvil)
• Stapes (Stirrup)

Eustachian tube: Connects middle ear to the throat.

Function:

• Amplifies sound vibrations and transmits them to the inner ear.
• Eustachian tube helps maintain equal air pressure on both sides of the eardrum.

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3️⃣ Inner Ear

Parts:

• Cochlea: Spiral-shaped, filled with fluid.
• Semicircular canals: Three loop-like structures.
• Auditory (Vestibulocochlear) nerve

Function:

• Cochlea: Converts sound vibrations into nerve impulses (hearing).
• Semicircular canals: Maintain balance and posture.
• Auditory nerve: Carries impulses to the brain.

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🧠 How We Hear (In Short)

1. Sound enters the outer ear.
2. Vibrations pass through the eardrum and ossicles.
3. The cochlea converts vibrations into nerve signals.
4. The brain interprets these signals as sound.

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⭐ Exam Tips

• Remember the order: Pinna → Eardrum → Ossicles → Cochlea → Brain
• Learn the names of ossicles in order: Malleus → Incus → Stapes
• Inner ear = Hearing + Balance

Let’s practice!