 Traffic. Hey everybody, Dr. O. In this video we're going to cover the levels of organization in a human body or the hierarchy of organization as a term you might see. The reason that this is so important is because this is kind of how we teach anatomy. We have to take what I would call a deconstructionist approach. We have to tear the body apart and break it down into its simplest level and then slowly build it back up, which is why anatomy classes start at the cellular and chemical level and then work into the cellular level and work their way through the organ systems to the organism. One thing I'd like to add here though is we don't do a really good job teaching you about the human organism at the end. We spend so much time tearing the body apart and looking at it organ by organ, tissue by tissue, system by system, but the job of putting it back together, like the term like holistic is what I think of, putting the body back together is very, very important. You don't truly understand this material until you understand how all the organ systems work together. I'll try to do a good job of making videos that kind of explain those connections, how your integumentary system is linked to everything else, but really putting it back together is when you know you've mastered this concept. I think it's actually, you even see, even in healthcare, you see this as an issue, right? Like a gastroenterologist is going to be an expert in one part of the body, but they don't look at the entire organism all the time. You're starting to see that things like stress and anxiety and depression can have an effect on the gut, but the gut can also have an effect on stress, anxiety and depression. So I do think we have to take a much more functional or holistic approach and really look at our patients as human beings, not to GI tracks with feet, right? So very, very important that you keep that in mind as we tear the body apart. Okay, so we're going to start with the lowest level and I'm going to add one to this list as well, but we start with the chemical level. So all anatomy classes start with that basic biochemistry, looking at atoms and different types of bonds, et cetera. So the chemical level is where we start and then we slowly start to put those chemicals together to form molecules. So that's where you look at water and we talk about osmosis and diffusion and how fluids move around your body, et cetera. But then we really dive in at the next level, but I'm going to add one here and I call it the organelle level. So the organelles are going to be the non-living structures that are used to create a cell, right? So the nucleus, the ribosome, the mitochondria, all these things we're going to cover, those are the organelles. So I do like to add that. So we have the chemical level, the molecular level. Then I add the organelle level before we get to the cellular level. And the reason I do is because the cell is the basic unit of life. But organelles are what build your cells. And this is, I want you to pause for a moment and think about that. This is when you take non-living ingredients, non-living building blocks and you put them together and out pops a living cell. This is one of the most amazing, complex things that happens in the universe. And just because it happens a gazillions of times doesn't mean that it's not really special. So think about that. How do we put, why am I alive? And the table I'm sitting in front of is not, right? We're both made of atoms. We're both put together, but you take these non-living building blocks and put them together and you now have living cells, all right? So just kind of pause and be awestruck by that. I like to do that whenever possible. So okay, the cellular level, the cell is the basic unit of life. So when you have an individual cell, we're at the cellular level. Then when you put them together, we now move to the tissue level. So a tissue is a group of cells that have a specialized function. So you see how we're building on each other. So we've built a cell, now we put cells together in tissues. Now when you take two or more tissues and put them together that work together to perform a function, we now have an organ. So now we're at the organ level. Then when you take two or more organs and put them together, we now, with a specific job to do, we now have an organ system. So like the picture here shows the kidneys would be an organ, the bladder would be an organ, but they work together along with the ureters and urethra to produce and store and get rid of urine. So they work together as an organ system. So each human has 11 organ systems. We teach a total of 12 because we do separate the male and female reproductive system. They're quite a bit different. So that's the organ system level. When you put those 11 organ systems together, we now have an organism, which would be the human in our case, right? So before we're done though, I want to take it a couple steps further because when you take a population then would be all of the same organisms living in a given area. So obviously the population of humans would be the next step here. And then we have communities. So communities are all the different types of species that live in a given area. And the reason I wanted to talk about this for an anatomy class is because it ties into our microbiology as well, is that we are not a human, right? We're made of somewhere in the neighborhood of 32 to 37 trillion cells, 80 to 85% of them are red blood cells. I find that so fascinating. But we also have 40 trillion microbes that live in and on us. So we are not a human, right? We are an ecosystem. We rely on these organisms. So hopefully if you take microbiology or watch my microbiology videos, you'll learn more about that. So just kind of add that to the end of this as well, that we are not just a human. We are an ecosystem. All right, so those are the levels of organization from the simplest to the most complex. And I hope this helps. Have a wonderful day. Be blessed.