 Hey everybody, Dr. O here. In part one, we covered the first four organ systems that are usually covered in AMP1. Now we're going to look at all the rest of the organ systems that are usually covered in an AMP2 class. Let's go ahead and get started with the endocrine system. So we had just mentioned that the nervous system is responsible for short-term maintenance of homeostasis, that stable internal environment. And that's because it makes decisions very, very quickly, but the responses last a very short amount of time. The nervous system is the opposite. It takes a long time for your hormones to respond, but the responses last a long time. So your endocrine system is going to be all these endocrine organs and tissues that produce hormones. Hormones are chemical messengers that are dumped into your body fluids and then control other parts of your body. So it says there regulates bodily processes. The key ones are going to be your metabolism. Your thyroid gland produces the thyroid hormone that regulates your metabolism. And then also long-term things like growth, development, pregnancy. These are going to be the things that the endocrine system controls. So that means the nervous system and endocrine system work to maintain homeostasis. Nervous system, real quick responses. So short-term control, endocrine system, much more long-term control. Now if you ask who's really in charge, it is the nervous system because the nervous system tells the endocrine system what to do. It's almost like the nervous system can translate these messages into long-term responses by telling the ear hormones are to be produced, et cetera. So that's your endocrine system. Next we have the cardiovascular system, one you probably know a decent amount about already. We'll cover blood, heart, and blood vessels separately, but what we'll treat it as one big unit. You can see here it delivers oxygen and nutrients to tissues, very important. As blood goes out to each of your cells, it delivers oxygen and nutrients. That's great. But at the same time, it also picks up carbon dioxide and waste products. So it removes waste products as well. Your blood and blood vessels are what allows your body to have a division of labor. Your liver can only focus on what the liver has to do because it's going to get the oxygen it needs from the lungs. How does it do that? Blood and blood vessels. So it's really, really cool. Then it says equalizes temperature in the body, and that's because blood is warmer the rest of your body. So your blood functions with your skin, like a radiator, to control body temperature. You get, if you're hot, warm blood rushes to the surface, so more heat will be radiated out of it, and then maybe some sweat, so you'll evaporate heat as well. If you're cold, your blood rushes to your core, which is why you get pale, because it's trying to keep your organs warm. So the carrying oxygen and nutrients to your tissues, carrying carbon dioxide and waste products away, and playing a big role in regulating body temperature are the key functions of your cardiovascular system. Lymphatic system. You see, we have lymphatic organs, lymphatic structures. Your lymphatic system works with your immune system, or we usually teach the two together, lymphatic and immune system, but the lymphatic system is primarily responsible for moving lymphatic fluid. So it says there returns fluid to the blood. Every day, about 3.6 liters of fluid is pulled out of your cardiovascular system, and it's carried back to your heart, but through your lymphatic system. Now why? The lymphatic fluid moves slowly, and it moves through what are called lymph nodes, or I like to give them as immune checkpoints. So while this 3.6 liters of fluid is being slowly milked back to your heart, your immune system and all your immune cells get to look at what's going on in there and look for pathogens and these types of things. So your lymphatic systems, they carry lymph, but these lymph structures all have a bunch of immune cells there, so your immune system can constantly be made aware of what's going on in your body. So that's the critical thing with lymphatic and immune systems. Respiratory system. You see here delivering oxygen, removing carbon dioxide. Obviously, every time you breathe in, you're breathing in oxygen. Every time you exhale, you're breathing out carbon dioxide, but there's more to it than that. Sound production. Your sinuses, your vocal cords, all of these things work together for the production of sounds. We can communicate. It also is a major organ, along with your kidneys, when it comes to maintaining pH balance in the body. And that's because carbon dioxide is turned into a weak acid called carbonic acid. So if your pH in your body is dropping too low and you're becoming too acidic, breathe out more carbon dioxide and you'll bring it back up. So your lungs do play a big role in maintaining the pH balance of your blood specifically. That's your respiratory system. Digestive system. The three words I think of when it comes to digestion or digestive system is digestion, absorption, elimination. So digestion is the chemical and physical breakdown of what we eat so that we can actually absorb it. Absorption is it's being carried from your gut, from your GI tract into your blood. And elimination is what is an absorbed passing through our body, like fiber, things like that. There is also some storage though. Your digestive system does play a role in storage of energy reserves as well. All right. So we'll again, we'll cover the entire GI tract later. This is just a real quick introduction, but the GI tract itself is the mouth to the anus. And then we'll look at the accessory organs like the liver and pancreas. Urinary system. You probably don't think much about the urinary system, but urine is filtered blood. So your urinary system plays a critical role in determining what's in your blood. It regulates the ion concentration and the pH of your blood. They're super important there. But we usually think about it producing, storing and eliminating urine. That's going to be what we think of. But notice there it says controls water balance because it determines how much urine you make is determined by how much fluid you have in your body. If you're dehydrated, you'll produce less urine because your body is holding on to that. So water balance, ion, electrolyte balance, the pH balance are all part of the functions of the urinary system. So we have a lot to learn, but it's going to be really cool. Male reproductive system. I mean, you know, both the male and female reproductive systems do two things the same. They both produce sex hormones. Males produce the male sex hormones. The androgens like testosterone. And they both produce gametes. So gametes are sex cells. In this case, with the male, it's the sperm or spermatozoa. And then it says delivers gametes to female. That's going to be with sexual intercourse. So we'll cover the external genitalia like the penis. And then we'll cover the entire male reproductive system on the inside as well. The tract that gets that sperm into semen and then the semen into the female vagina. Female reproductive system. So it produces the sex hormones. In females, the big ones are the estrogens and progesterone. The gamete would be the oocyte or the egg, but that's where the similarities end. Because the female system is much more complex because once you have a fertilized egg, the female reproductive system has to support the embryo slash fetus until birth. So with the womb, the uterus. And then after birth, produce milk for the infant with lactation. So there's a lot more going on with the female system. Okay, those are all the organ systems that we're going to cover throughout these two semesters. I hope this helps. Have a wonderful day. Be blessed.