How does the stapes work in ear?

The stapes is the third and smallest bone in the human body, located in the middle ear. It plays a crucial role in the process of hearing by transmitting vibrations from the anvil (incus) to the inner ear. Here's how the stapes works:

1. Sound waves enter the ear: Sound waves travel through the outer ear and cause the eardrum to vibrate.

2. Vibration of the eardrum: The vibrations of the eardrum are transmitted to the middle ear bones, including the malleus (hammer) and incus (anvil).

3. Malleus and incus: The malleus is attached to the eardrum, and it connects to the incus, which is located in the middle ear cavity. As the eardrum vibrates, it causes the malleus and incus to move back and forth.

4. Movement of the stapes: The incus is directly connected to the stapes, which is the final bone in the chain of middle ear ossicles. As the incus moves, it causes the stapes to move as well.

5. Transmission of vibrations to the inner ear: The footplate of the stapes fits into an opening called the oval window, which leads to the inner ear. As the stapes moves, it causes the oval window to vibrate.

6. Conversion to fluid waves: The vibrations of the oval window are transmitted to the fluid-filled inner ear, specifically the cochlea. The cochlea is a spiral-shaped structure that contains the auditory receptors known as hair cells.

7. Stimulation of hair cells: The fluid waves generated by the stapes' movement cause the hair cells in the cochlea to bend and sway. This bending of hair cells triggers electrical signals, which are then interpreted by the brain as sound.

In summary, the stapes serves as a bridge between the vibrations of the middle ear bones (malleus and incus) and the fluid-filled inner ear. By transmitting these vibrations to the oval window, the stapes plays a crucial role in the process of hearing and allowing us to perceive sounds.