The Integumentary System

The Integumentary System (Layers of the Skin)
    The larges organ of the human body, the skin, contains two main layers such as the epidermis and the dermis. The epidermis, being the outer layer of the skin, is a keratinized stratified squamous epithelium which does not have direct blood supple. It contains four different cell types including keratinocytes, melanocytes, Merkel’s cells, and Langerhans’ cells.
    Keratinocytes are responsible for producing keratin, which is where skin gets it strength and flexibility. Keratin also waterproofs the visible layer of the skin. They are also the most common cells. They derive from the deepest part of the epidermis from cells which are undergoing almost continuous mitosis. Considering the location in the body, keratinocytes can be organized in four to five layers.
    Melanocytes produce melanin, which is known as a dark pigment that gives skin its color. The body of melanocytes are hard to distinguish in an ordinarily LM preparation, because the melanosomes are mainly located the processes of the cells.
    Merkel cells are present in little numbers between the epidermal layer and the dermal layer. They function as sensory receptors. Lastly, Langerhans’ cells arise from bone marrow and move to the epidermis along with other areas of the body, while containing stratified squamous epithelial tissue. They possess antigens that help in the immune system. All these cell get their nutrients from the dermis; however, it’s only the cells deep in the stratum basale that receive nourishment.
    The stratum basale, which is the deepest layer of the epidermis, consists of one layer of columnar and cuboidal cells resting on the basement membrane. The cells in the stratum basale divide continuously. They are known as the stem cells of the epidermis. As the new cells are created, the older cells are pushed to the surface of the skin and die. The dead cells are then removed in a process known as desquamation. Desquamation is...