Passive Transport: Diffusion (Nursing)

00:00 So when we talk about passive processes, again, there's three major ways that we're going to go through these processes.

00:09 Again, in a passive process, we're moving down the concentration gradient or from an area of high concentration to an area of low concentration.

00:19 So this can be performed in multiple ways.

00:22 In simple diffusion, non-polar, small uncharged molecules are able to simply just pass through the membrane.

00:30 Examples of things that would fall under this category include things like oxygen which is able to just passively go through the membrane.

00:40 If something cannot just pass through the membrane because it is too polar or too highly charged, then we need help.

00:48 And that's when we use our facilitated diffusion.

00:51 And so in this way, we use either channel proteins or carrier proteins.

00:57 In channel-mediated diffusion, these channels allow certain substances to move across the membrane.

01:04 These channels are usually specific for a substance and are not going to allow just anything to pass through.

01:11 Examples of channel proteins include things like aquaporins which are specific for water and allow water to go inside and outside of the cell as well as certain ion channels which are important for our nerves and our muscles and lots of other cells in the body.

01:28 And then the third type of diffusion is carrier-mediated diffusion which involves the use of a carrier protein and much like the channel mediated diffusion, we're going to move substances down the concentration gradient using a protein that will change shape in order to move things from one side to the other.