In this video, we're going to continue to talk about the cells of the epidermis. Notice in the top right, we have the diagram of the integumentary system with only the epidermis, or the outermost layer of the skin, colored since that's the main focus of this video. Recall from our previous lesson videos that we've already covered the most abundant cell type in the epidermis, which are the keratinocytes. In addition to those keratinocytes, there are also three other main types of cells found in the epidermis: melanocytes, dendritic cells, more specifically Langerhans cells, and tactile epithelial cells or Merkel cells.
The melanocytes, as their name implies, are specialized epithelial tissue cells that produce melanin. Melanin is a specialized pigment or molecular complex that interacts with light, protecting our skin from UV light or ultraviolet light from the sun, which can cause UV damage. Melanin, therefore, protects our skin from UV damage. These melanocytes are found in the deepest layer of the epidermis called the stratum basale. Melanocytes are essentially factories of melanin production. We'll learn later in our course that the melanin plays a major role in skin pigmentation or skin coloration, and the melanin produced by these melanocytes can be transferred to neighboring keratinocytes so that they also carry the melanin.
Later in our course, we'll discuss more about these melanocytes. The next type of epidermal cell we'll discuss in our lesson are the dendritic cells, which are a type of immune cell. Dendritic cells are found in many different regions of our body, and those specifically found in the epidermis are called Langerhans cells. Langerhans cells, the name of a specific scientist, help initiate immune responses. They scout the epidermis looking for signs of invasion or infection and, upon finding such signs, can migrate out of the epidermis into the lymphatic system and travel to nearby lymph nodes where they activate immune cells to help eliminate the invader or pathogen.
The last type of epidermal cell in this lesson are the tactile epithelial cells, also called Merkel cells, named after a specific scientist. The term "tactile" here is associated with the sense of touch. These tactile epithelial cells, or Merkel cells, are specialized epithelial cells that work with nerves to detect touch and allow for sensations of touch. Like melanocytes, tactile epithelial cells are also found in the deepest layer of the epidermis. We'll discuss more about this and additional structures involved with sensations of touch in the dermis in later lessons when focusing on the dermis.
If you look at the image below, you'll notice this middle part is a zoom-in of the epidermis. You can begin to see the layers of the epidermis and the three main types of cells we've talked about. Notice that the vast majority of the cells outside of these dotted circles are keratinocytes. In the deepest layer of the epidermis, you can find melanocytes (represented in purple) producing melanin, which plays a major role in skin pigmentation. The next cell depicted in green is the dendritic cell, more specifically the Langerhans cell, which helps initiate immune responses. In the bottom right in blue is the tactile epithelial cell, also known as a Merkel cell, closely connected with the nervous tissue in yellow beneath, allowing for sensations of touch together.
This concludes our brief lesson on the other epidermal cells, and we'll be able to get some practice applying these concepts and learn more about the epidermis as we move forward in our course. I'll see you all in our next video.
