Balance: Otolith Organs

00:01 The Otolith Organs.

00:03 These also work on the structure of hair cells. Bending in one direction versus another.

00:10 These structural bent is all towards the kinocilium.

00:15 This is the tallest component of the hair cell.

00:19 So if you’re bending in that direction, you will get a depolarization.

00:23 If you bend in the opposite direction, you will get a hyperpolarization.

00:28 So how otolith organ works? Are you, are now putting these various lowcals of hair cells? All in a little different configuration.

00:40 So that in any movement that you get in the head or if there is linear acceleration that takes place.

00:46 Some of the hair cells will be bent depolarized, some will be bent and hyperpolarized.

00:53 It is this coordinated amount of information that’s sent back to the brain that helps it understand where it is in space.

01:04 So this otolith arrangement becomes very important. Which, which way you’re going to bend the hair cells.

01:11 You can orient the hair cells in multiple directions at the same time.

01:16 And that is what the otolith organs do.

01:19 You have a different orientation of these hair cells along the different planes.

01:25 That way, you can tell when a little movement is made in the head in one direction or another because some of the hair cells are being depolarized and other ones are being hyperpolarized.

01:36 All depending upon their orientation.

01:40 How do these cells get bent? There is an interesting process in where there’s gelatinous material, as well as small stones that are made up of calcium to have a little bit of inertia associated with these gelatinous material.

01:58 Therefore, when they’re bent, they will have a little weight to them and will want to move.

02:03 And as the gelatinous substance moves, they bend the hair cells.

02:08 You might ask, okay, why do you need this gelatinous substance? I mean why stick these hair cells and something like jello? The reason is because it allows for better protection of the hair cells.

02:19 Imagine hair cells are very delicate.

02:22 If you just simply rub stones allover these hair cells you would break some of them off.

02:27 But having them mixed in these jello-like substance, you can move the jello round a little bit.

02:34 And with that does is allow for the hair cells to move but still be in a protected environment.

02:41 So what activates these otolith organ hair cells? We mentioned movement the number of times but simply the relation to gravity.

02:51 Are you in a standing position? Or you’re laying supine. Or maybe you’re sitting in the upright position.

02:58 Or you’re tilting you're head one side or another? All of those changes are sensed by the otolith organs.

03:06 Because remember that gelatinous substance has a little weight to it.

03:10 So wherever you are imposition to gravity, it will poll on that gelatinous substance and that gelatinous substance will cause some hair cells to depolarized, another hair cells to hyperpolarized.

03:26 Interesting linear acceleration also does these.

03:30 So if you’re driving in a car in the faster you go you get these feeling of movement.

03:36 Why because they are, that gelatinous substance is being moved back as you accelerate forward.

03:43 And that movement of the gelatinous substance stimulates or depolarizes some of those hair cells.

03:51 Same thing it can happen if ride in an elevator.

03:54 So you could sense linear direction upwards and downwards just like you can forward and back.