Our skin is our largest organ, which makes up the integumentary system, it does a lot of functions, like protecting us from outside chemicals and pathogens like bacteria, fungi, and viruses, and protecting our internal organs from damage. The human skin helps maintain a homeostasis state and helps us maintain body temperature, and fluid balance (OpenStax, 2018.) The skin is where vitamin D is produced, our skin has sensory functions like for example bugs crawling on the skin and we become aware of this. The skin has different layers and tissues, like the epidermis layer which has epithelial cells. Within the epidermis there are different cells called keratinocytes, these are cells that make keratin which is protein, they help cells become tough and water resistant and are produced at the bottom layer of the epidermis and are pushed up to the top of the epidermis where they are considered cornified cells which are flattened, tough and dead because of losing their organelles and loaded with keratin(OpenStax, 2018.) From the outer layer to the inner layer of the epidermis the layers are classified as stratum, you have the outer top layer called the stratum corneum, this layer has dead cells or cornified cells which are continuously being replaced by cells coming from below the layer. The second layer is stratum lucidum, which is not in all skin areas but can be found in the bottom of the feet and or palms also this layer has cornified cells, but a special type of protein giving them a transparent look(OpenStax, 2018.)
The third layer of the epidermis is stratum granulosum, within this layer keratin cells that are pushed from the lower layer into this layer develop a flattened structure and contain granules that will later travel to the top layer and become cornified cells. The fourth layer is called the stratum spinosum which looks spiny and contains many keratinocytes cells, also there is a type of cell in this area that will consume worn-out cells and bacteria. The fifth layer which is the deepest of the epidermis called the stratum basale consists of one layer of cells called basal cells which is doing mitosis and gives rise to the keratinocytes cells above. There is a skin condition called Callus which generally forms on the feet or fingers like extra thick skin. This is formed because the baseline layer is trying to respond to frequent abrasions by making more cells to prevent blisters. This affects the quality of life by causing pain and harming healthy tissues normally affecting farmers and athletes. The stratum basale layer has other types of cells called melanocytes which are responsible for making a protein called melanin which gives skin colors and protects us from harmful UV rays from the sunlight(OpenStax, 2018.). The melaninocytes are transported to the keratinocytes in organelles called melanosomes. Merkel cells are also found in the stratum baseline they work with the nervous system to help us have a sense of touch. The stratum basale layer