Cytoskeleton: Cytoplasm (Nursing)

00:00 So we've discussed the plasma membrane extensively. Now let's switch gears and move to the inside or the internal environment of the cell. The inside of the cell consists of the cytoplasm, and in the cytoplasm you have the cytosol or the intracellular fluid that's found in the cell, and you have organelles which are the specialized structures that are going to perform different functions inside of the cell. So before we talk about all of the different structures, let's talk about the cell's skeleton also referred to as the cytoskeleton. The cytoskeleton are different types of filaments and tubules found throughout the cell that give the cell its structural integrity or its shape. And they also allow for movement of substances across the cell as sometimes they are intracellular highways and surface street on your cell.

01:00 So, there are 3 main cytoskeletal elements; the smallest of them are the microfilaments also known as actin and the medium size is going to be your intermediate filaments, and the largest of them is going to be your microtubules. Each of these cytoskeletal elements plays an important role in the cell. Your actin microfilaments are very important for maintenance of shape of the cell and they also allow for some movement of substances through the cell especially at the cell surface. The intermediate filaments are usually surrounding the nucleus of the cell and helped to create the nuclear lamina or the area around the cell so that the nucleus is in the right place of the cell. And then the microtubules which extend from near the nucleus toward the periphery of the cell is also very important for structure as well as transport of cargo throughout the cell using the vesicles in the cell. So the vesicles are going to basically travel along these microtubules. So the microtubules extend from a specific structure known as the centrosome. And the centrosome is made up of 2 centrioles which are at 90 degrees to each other and are located just next to the nucleus. And so from the centrosome, these microtubules are going to grow or radiate from this area of the cell. This is especially important when you're talking about mitosis as the centrosomes play a central role in the production of spindle fibers in mitosis. Another structure that is derived from the microtubules of the cell are the cilia and the flagella. These both involve movement, either movement of particles or movement of the cell themselves. For example, in the respiratory system, you have cilia that allow you to cough up substances that you don't want getting down into the lower respiratory area of your body. And when you think of flagella, think of sperm and their ability to swim toward an oocyte in order for reproduction to occur. So the cilia and the flagella in our bodies are going to move in different ways. The flagella are usually going to move in a propeller-like or round motion whereas the cilia in our body are going to beat back and forth. So the analogy that I like to use is a boat. If you have the opportunity to have a motor boat, the propeller on the back of the boat is going to propel you forward.

03:52 Whereas if, for whatever reason, your motor doesn't work you always can use the ors and move back and forth in order to get where you're going.