Which chamber is known as the lowermost chamber of the cochlea?

The correct answer is the scala tympani, which is indeed recognized as the lowermost chamber of the cochlea. The cochlea is a spiral-shaped structure in the inner ear that plays a crucial role in hearing by transforming sound vibrations into neural signals.

The scala tympani is situated below the scala media and is filled with perilymph fluid, which helps in the transmission of sound waves. It extends from the round window of the cochlea to the apex, or the top, of the cochlea. When sound waves enter the cochlea, they cause pressure waves in the perilymph of the scala tympani, which then contribute to the movement of the basilar membrane and the stimulation of hair cells, leading to the perception of sound.

In contrast, the scala vestibuli is located above the scala media and also contains perilymph but is responsible for transmitting sound waves from the oval window. The scala media is the middle chamber filled with endolymph and is critical for the electrochemical processes necessary for transducing sound. The vestibular system refers to a different part of the inner ear involved in balance and spatial orientation, not directly related to the chambers of the cochlea. Thus, recognizing the scala tymp