 Okay, I said it and I really think like this is probably the coolest thing that I've learned about this teaching year. This is so interesting. So we already mentioned that in stratum basale, there are these awesome cells called melanocytes. And the melanocytes are embedded in there and I think I honestly can't remember anything. I can't remember if I told you that all of us, no matter what color our skin is, all of us have the same number of melanocytes in our skin, no matter what color our skin is, which is like super mind-blowing to me. So these melanocytes, I'm going to pull this over here. I'm going to use the diagram over here to illustrate what's going to happen with these melanocytes, but I wanted to be able to take some notes as well. So first of all, the melanocytes produce these vesicles of melanin and the vesicles, so look, the melanocytes make these vesicles called melanosomes. Melanosomes. And all the melanosomes are like lysosomes. They're just vesicles. They're cell membrane bubbles of melanin. Melanosomes are filled with melanin. And melanocytes produce melanosomes. They then exocytose the melanosomes into the epidermis. Okay, so think about this for a second. They basically take their, they're producing all these bubbles of melanin and they basically release the bubble. They barf the bubble. They reverse-yumptualize the bubble out into the rest of the epidermis. The keratin, keratinocytes, keratinocytes. Keratinocytes. Got it. I got it. The keratinocytes-yumptualize endocytose. The melanosomes, melanocytes, exocytose, melanosomes. Keratinocytes, endocytose. Melanosomes. Keratinocytes now have these melanosomes inside them. The melanosomes? Oh, my gosh, this is so freaking cool. The melanosomes surround, I'm going to write that down, melanosome surrounds, that says surrounds the nucleus. Hi. Dude, the melanosomes surround the nucleus to protect it from UV light. And why do you need to protect your nucleus from UV light? Because UV light can cause DNA inside your nucleus to break. And if your DNA breaks, draw your brain back to the glory days of Bio 1. If your DNA breaks, then you aren't going to be able to make the proper proteins. If you think about cells making melanosomes and melanin, that's all protein thanks to a gene that's telling me what to do. So if you throw some UV light in there, yeah, that's probably not going to be a great thing. Let's protect the nucleus from the UV light. This seems like a super smart thing to have in your epidermal cells. It seems like, yes, please, I would like some more melanin so that it can go in there and protect my DNA from UV light. Brilliant, this is a win-win situation. Not all of us have the same number of melanocytes, not all of us have the same pigment of our skin. In fact, skin pigment is incredibly diverse. And there are three ways that we can generate different amounts of melanin in the overall, what, epidermis. First of all, some cells, this is genetic, some melanocytes make full melanosomes, okay? So some of us fill our melanosomes like half full, and others of us like fill them like crazy mad, awesome full. Some have more. So you fill your melanocyte super full. No, excuse me, it's not your melanocytes that you have more. Your melanosome, which is the bubble. You fill your bubble really full of melanin, and that's going to increase the amount of pigment in your epidermis. Some cells, because of genetic messages, some cells make more melanosomes. So they have more bubbles. They make them more, they make them faster, they fill them fuller. If you do those two things, then you are going to have more pigment in your skin. There's one more. There's two flavors of melanin. So some melanocytes produce a sort of brown-black form of melanin, and other melanocytes produce like this red-yellow form of melanin. And you can imagine that if you do a mix and match those three variables, that you can end up with an incredible diversity of skin color. And I just have to take a minute to say that, especially in the United States in 2018, and the leadership of our country, the conversations have, there have been a lot of conversations about skin color and what that says about someone. And we have leadership that is sort of modeling this, that we can actually know something about a person based on the genetic, biological phenomenon of combining melanocytes that make lots of melanin, they make lots of melanosomes, they fill their melanosomes full, or they make certain colors of melanin. And if we combine all those characteristics, there is a definite set of humans that think that that says something about who you are, that I can know something about who you are, or your values, or what you might do, or your intelligence. And we're sort of having it modeled for us right now, that that is appropriate or accurate. I was really struck by this physiological process because it just is so clear that that right there is molecules doing their thing in layers of skin that we have to know the names of, and it has nothing to do with anything else, which then takes me to, is it true that the color of your skin affects the experience that you have in this world? Absolutely. And it's not okay. And it's not okay that our president is suggesting that that is appropriate. And remember, it's nothing, anything that our world is going to say about skin color and what that means, there is no anatomical support for that. It is genetic and protein and it's super cool and I seriously want to give high fives to all my melanocytes and all of everybody else's melanocytes because it's an amazing thing that it just did, but it is a social construct that says anything about the person that you are. I am a glass half full human. I like to see the world in a rosy way and it means that it has been really hard this last year having the leadership in the United States that we have because it's disgusting and it's embarrassing and it's horrifying. There's no excuse. There's no excuse for it. But my glass half full self looks at this situation that we are in here and the modeling that's happening and the statements about skin color that are being made. And I think we're having conversations that we wouldn't have been having and I think that we are holding, I think we're learning and we're having standards, we're holding our own standards and we're defining our own standards and I think that that is going to mean that after we're done with this, we're going to be better off. Okay, I hope that that's true. And now I'm going to go cry and then I'm going to come back and tell you about other things that are in our skin.