Cilia and Flagella Movement

00:01 Now, we're gonna use some of these cytoskeleton elements to move things, maybe even move the whole cell.

00:06 So, I haven't talked about it but actin because it's so dynamic, is it polymerizes and depolymerizes as it breaks and as it branches, that allows us to build little cytoskeletal extensions and those cytoskeletal extensions allows cells to ooze to kind of move and crawl.

00:25 So, that's one form of motility associated with the cytoskeleton.

00:29 Another way is to use microtubules to actually get big movements and big movements, I'm talking about flagella in a sperm or talking about cilia in the respiratory epithelium that allows us to move mucus up out of the lungs.

00:45 So, microtubules form the basis for cilia and flagella and what is shown here is basically an organization of a cilia.

00:55 We would see something similar if we looked at a flagella and it's nine couplets that's on the right-hand side, we see nine things around the outside and those are microtubules organized in a particular way in a central core of two couplets or two microtubules.

01:12 That's surrounded by a plasma membrane.

01:14 Now, going back up through the left side, we see the microtubules, the nine plus two.

01:18 We have a plasma membrane and these couplets are connected by dynein arms.

01:23 So, they are gonna hydrolyze ATP to allow sliding against the adjacent couplet and by coordinating the ATP, we can actually have the whole thing move like that and that's how we're gonna get movement out of cilia and flagella.

01:41 It's coordinated through the basal body.

01:43 So, the basal body is similar to the centriole that we talked about in when we were talking about microtubules emanating from that area near the nucleus.

01:53 The basal body is going to be the source of generating the ATP that's gonna allow the dynein motors to slide the microtubules one over the other and coordinate the beating and we're gonna get nice waves.

02:05 We're not gonna have random beating of cilia in the airways.

02:08 We're gonna have them coordinated as they beat out mucus and bacteria and stuff.

02:14 So, and the cilia or the basal bodies of the cilia have a typical triplet microtubule structure.

02:22 So, this is all very complicated. The detail's not too important.

02:25 It's the cool concept here that we're gonna get movement out of this.