[MUSIC] Okay, so let's talk about the cochlear amplifier. We're going to, first, describe, in this first segment, we're going to describe what's the problem that the cochlear am, or where are the problems that the cochlear amplifier solves, and there are two. First of all, we, this shows, we're back to our, our image where there, this is the, the breadth of this, the height of this is proportional to the amplitude of the stimulus. So the stimulus has grown in intensity in the external ear, but we've lost intensity in the middle ear. And then we would lose more oop, it would be down here if nothing else happened. The amount of sound coming into the, inner ear, would also be very, very small, and, we would be, we would have very poor, sound detection. So one problem is this amplification. We, we need to boost up. The second problem, if we come over to the board, relates to, the, the effect of this auditory prism. Now the, the prism that Buchesi found, it does a great job of differentiating between ten thousand hertz and, and a thousand hertz. It doesn't do a great job of discriminating between, say, 500Hz and 502Hz. But you, most of you, can tell the difference between 500 and 502. You can make very fine judgments. You can make discriminations between sounds that arrive here and here. But vicase's prism is too gross, too coarse to allow for these two to these two sounds to be discriminated. And so the second problem the cochlear amplifier, is going to help us with is to discriminate and make the tonotopy of the cochlea even finer than it would be with just the, the, just the prism that is, that, that results from the physical structure. So, cadavers have, are only able to use the prism component of amplifying and we knew from a long time, for a long time. We have known for a long time that, in fact, there had to be something that amplified sounds even more and that refined the, the frequency discrimination of sounds even more that was present in living cochlea, but not present in dead cochlea. And that came to be called, the cochlear amplifier. So, the cochlear amplifier, the search was on. And in the next segment we will find that cochlear amplifier. [MUSIC]