 There are three other true endocrine glands that I want to talk about. You know, the adrenal glands and the pituitary gland, those are considered true endocrine glands even though they have neural tissue associated with them. These other structures literally are pure endocrine. They don't have other stuff going on. The first one is actually found in the brain. So orient yourself to the sagittal view. Remind yourself, this is interesting, that here's pituitary gland. We've already talked about pituitary. Remember our brain study and remember that structure that was part of the epithalamus and in fact was the only structure that we associated with the epithalamus and that's the pineal gland. I can't remember. Did we talk about what hormone is produced by the pineal gland? It's melatonin. And melatonin is associated with, I can say it, mind's all messed up. Seriously? Don't even start listing off things of mine that are all messed up. Oh, come on. Circadian rhythms. Because you know, it's only one o'clock in the morning and I'm going to be teaching in seven hours. My circadian rhythms are garbage. I am totally a nocturnal human. So I don't know what's going on with my pineal gland and really they don't know a whole lot about the pineal gland and its function, what this melatonin actually does. But it's a true endocrine gland. The other true endocrine gland that we're going to look at is the thyroid. Oid. That says thyroid. Of course it does. The thyroid is a butterfly-shaped endocrine gland. It's anterior to the trachea. This is my trachea back here. Thyroid cartilage is superior. The thyroid cartilage of the larynx is superior to the thyroid gland. It kind of like nestles around your trachea. The thyroid gland is, oh, really important. We're going to look at the histology of the thyroid gland. It's actually made of these structures that are, I think they're called vesicles. I actually can't remember. Follicles, which look like little vesicles. There are gillians of follicles in the thyroid gland, and these cells right here are simple cuboidal epithelium. Don't they totally look like it? And they produce thyroid hormone and dump it into this space in here. And so it's like a thyroid hormone storage refrigerator. And these cells just pack it full of thyroid hormone. When you need thyroid hormone, these cells allow you to dump it into the bloodstream. Thyroid hormone, what does it do? Holy metabolism, okay, thyroid hormone increases metabolism and makes you burn more calories, which most of us are like, dude, that's awesome. Go, thyroid, go. If you have a lot of thyroid hormone, you get hot. I don't have very much thyroid hormone because I'm always cold, but it's important. Embedded in the thyroid gland, look and be amazed. See that right there? See that one and that one and that one? Guess what that's called? I got to make it a different color. That's the parathyroid gland. And you can actually see the parathyroid gland when you look at thyroid histology. The parathyroid gland interestingly sends a message, makes parathyroid hormone, which heads to the kidney and stimulates the kidney to make vitamin D. And vitamin D is involved in increasing calcium absorption from the digestive system. What? Oh my gosh, seriously, the endocrine system? The endocrine and the nervous systems, I just, all your systems are so cool. All right, those are our three other true endocrine glands. Next section, we're going to look at all the crazy, like what about this thing? What is that thing? Nobody knows what that thing is except I do. And I'm going to tell you in the next one because that is not an endocrine gland, but it contains endocrine cells. Okay, let's talk about it.