In this video, we're going to refocus our attention on the human microbiome. And so first, we need to recall from some of our previous lesson videos that the microbiome is also sometimes referred to as the normal flora. The microbiome or the normal flora refers to the communities of microbes that grow on and in the bodies of all humans at all times. These microbes that are part of the microbiome or normal flora live in symbiotic relationships with humans, and they can be further classified into 2 groups. They can be classified as resident microbiota, or they could be classified as transient microbiota.
Resident microbiota, as its name implies, include microbes that are going to be residing in our bodies for long periods of time. The resident microbiota are microbes that are almost always on or in the host for extended periods of time. The transient microbiota, on the other hand, includes microbes that are only temporarily found on the body for relatively short periods of time. Of course, pathogens, disease-causing agents, are going to be considered transient microbiota. They're only on us for relatively short periods of time in most cases, but not in all cases.
Now, if we take a look at our image down below, we can get a better understanding of the difference between resident and transient microbiota. On the left hand side, notice it's an image focused on the resident microbiota, which are going to be microbes that are almost always on the host for extended periods of time. Notice here we have a cartoon showing you these microbes that are residing in the lungs, calling the lungs "home sweet home." And notice it's saying, "I love our home in the lungs. I never want to leave." They seem pretty comfortable and relaxed and they don't look like they're going anywhere anytime soon. These resident microbiota are on or in our bodies for long periods of time.
On the right hand side, we're focused in on the transient microbiota. The transient microbiota, of course, are only found in our bodies for temporary periods of time, or short periods of time. Notice that these microbes right here don't look like they're sticking around much longer. They've got their bags packed and they're ready to hop on the microbe transit to make their way to their next destination because they're not going to remain in or on the host for extended periods of time. So notice their next stop is going to be outside of the host, and again, they are going to be temporarily found on the body.
This here concludes our brief intro to the microbiome and normal flora and our intro to resident and transient microbiota, and we're going to continue to talk more about the microbiota as we move forward in our course. So I'll see you all in our next video.
