all right so let's take a look at the dermis now so that was the epidermis we just covered so it looks like a look at the dermis so the dermis a thick layer of skin beneath the epidermis dermis kin a P means above above the skin all right so the dermis has a lot of blood vessels which we can see in here all right so it OSHA's and supports the epidermis it is made of connective tissue it's actually dense irregular connective tissue is what makes up the skin the majority of our dermis it also contains nerve cells for touch and pressure those mice or scar puzzles and pacinian corpuscles which we talked about in lab now let's take a look at this top layer here of the dermis and this is known as the papillary layer so this layer is actually made of areolar connective tissue and it has many blood vessels which you can see there all right it also has these projections here these things that project up and those are known as dermal papilla and so those are projections of dermis into the epidermis if we go to the next picture you can see here these dermal papilla here here's a dermal papilla here so and this is your showing those dermal papilla once again alright so these what the dermal papilla do is they cause these epidermal ridges so this right here is an epidermal ribs that's another epidermal Ridge alright and so what happens in thick skin is that thick skin amplifies these epidermal ridges so we get start to see them on the surface there all right so oh these also house touch receptors those misers core puzzles so thick skin as I mentioned amplifies those ridges and this is what creates fingerprints now fingerprints as you should know is caused by genetics but also environment is going to influence that trait pretty much like any other trait that we have and so because of that because it's not just genetics but also in the environment no two fingerprints are the same right so even identical twins will not have the same fingerprints alright so let's go back to this picture now much of the dermis is what we call the reticular layer and it's made of dense irregular connective tissue now what happens here is in this as I said it's a dense irregular connective tissue but because it's irregular it's going to have some areas that are more dense than others all right and these less dense areas become what we call tension lines so when you move right it's going to create these lines from your skin all right and so what surgeons try to do is they try to cut in the direction of those tension lines because what that does by cutting in the direction of the tension lines the skin here pulls in this direction so it's not going to pull that incision open if you cut against it tension lines well you're pulling in that direction that's gonna pull those open just think about if you've ever gotten you know like a scrape or cut on your knee you're constantly pulling against that when you bend your knee that's actually essentially the same thing that's happening here all right let's move on to the subcutaneous so that's that lower layer here technically not part of the skin so this is also known as the hypodermis so this is a layer beneath the skin this is made of areolar in a post tissue so you can see all the adipose in there and it has all the functions of adipose tissue so it's in stores energy it's there for cushioning also there for insulation the subcutaneous also has a lot of blood vessels that's why you know can we get stuck with a needle a lot of times it's a hypodermic needle so it's going into the hypodermis all right let's take a look at skin color now there are three pigments that make up our skin one is melon and that is the only pigment that is made by the skin and as I mentioned earlier it protects against ultraviolet radiation or ultraviolet light all right this accumulates in the cells and the stratum basale in the stratum corneum and there are two forms - one is called you which is a brownish black pigment and the other one is called pheomelanin which is a reddish yellow pigment and so your skin color is based upon you know what type of melanin that you produce and also your ancestral heritage if your ancestral heritage is closer to the equator where you get sun year-round you want to have a lot more eumelanin because that's going to protect more against ultraviolet radiation if your ancestral hair just was further away from the equator what you want to have is more pheomelanin and then because your skin is going to be lighter and that's gonna allow you to produce vitamin D and so that's why we see differences in skin color and people another pigment that's found the skin is called carotene and carotene the first part of that word spelled like carrot right and carrots our orange in color and so carotene is a yellow to hornish pigment and that accumulates in the stratum corneum and also the hypodermis and you get carotene from your diet so not just in oranges carrots but any green leafy plant will have it as well because carotene is a photosynthetic pigment next is hemoglobin now hemoglobin what hemoglobin is is a protein that transports oxygen in our blood and hemoglobin gives blood its color now this may come to a shock to some of you but our blood is always red all right so hemoglobin gives our blood its color which is red and so that gives our skin a pinkish coloration do the hemoglobin that's there