Starting on 05/18: On Tuesday 05/19, write 250 words about what you've learned from the attached ppt.

The human skin is a major organ of our integumentary system and its main function is to act as a barrier and provide protection from mechanical impacts and pressure, variations in temperature, microorganisms, radiation and chemicals. It’s the largest organ in the body and serves as its protective covering. It’s the body’s primary defensive agent to prevent infectious organisms from entering the body. Additionally, the skin plays a significant role in thermoregulation and is vital in preventing overheating or overcooling of our body. As an organ, the skin can be divided into three separate zones: epidermis, dermis, and subcutis. The epidermis is the overlying squamous layer and is organized into further layers that is used when describing histological findings. In the most superficial layer of the epidermis, the horizontal elongation of keratinocytes continues and displays a loss of their nuclei. They continue to become less eosinophilic and less “pink”. This layer is called the stratum corneum. This is the most superficial layer and is an important clue not only to the presence of certain types of skin conditions, but also to their age. The next layer of the epidermis is known as the stratum spinosum. The deepest layer of the epidermis is the stratum basale, which is the site of mitosis and the home to melanocytes. The melanin pigment produced by these cells protects the skin from the sun as an increase in melanin correlates to higher pigmentation of the skin. The dermis is the layer of connective tissue and supporting structures that is directly beneath the epidermis. It is made up of collagen and elastic fibers that provide the tensile and elastic properties of the skin. The dermis is home to the three types of glands of the skin: sebaceous, eccrine, and apocrine. These glands are responsible for sweat and oil production as well as temperature regulation. Deep to the dermis is the subcutis, which is composed mostly of fat, blood vessels, nerves, and connective tissue.

• Alldredge, Brian K, Mary A. Koda-Kimble, and Lloyd Y. Young. Applied Therapeutics: The Clinical Use of Drugs. , 2013.