At which location along the basilar membrane are the highest-frequency sounds detected?
**Core Concept**
The **basilar membrane** plays a crucial role in sound detection and frequency differentiation within the **cochlea** of the inner ear. It is tonotopically organized, meaning different sections respond to different sound frequencies. The mechanical properties of the basilar membrane vary along its length, allowing for this frequency differentiation.
**Why the Correct Answer is Right**
The correct answer is related to the fact that the basilar membrane is narrower and stiffer at the **base** of the cochlea. This narrower and stiffer section is more responsive to **high-frequency sounds** due to its mechanical properties, which allow it to vibrate more rapidly. In contrast, the **apex** of the cochlea, which is wider and more flexible, responds to lower frequency sounds.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it does not specify the correct location for high-frequency sound detection.
**Option B:** Incorrect as it refers to a location that might respond to lower frequencies.
**Option C:** Incorrect because the apex is responsible for detecting lower frequency sounds.
**Option D:** Incorrect as it is not related to the specific mechanical properties of the basilar membrane that allow for high-frequency sound detection.
**Clinical Pearl / High-Yield Fact**
Remember, the tonotopic organization of the cochlea is key to understanding how we differentiate between various sound frequencies. Damage to specific parts of the cochlea can lead to hearing loss in specific frequency ranges.
**Correct Answer:** D. The base of the cochlea.