By: Madison Lipscomb, Shae Eggert, McKenna Hagan, Malik McFarlane Skin Anatomy By: Madison Lipscomb, Shae Eggert, McKenna Hagan, Malik McFarlane

Layers of the Skin

Epidermis Definition: The upper or outer layer of the two main layers of cells that make up the skin. Provides a waterproof barrier, and creates skin tone Serves as the protective layer, i.e. a parka that you would wear in the winter to protect against the col., The inside is lined with soft fleece, providing a layer of warmth. But the outside is made of a strong waterproof material that lets nothing through. It is a similar situation with our own epidermis. The cellular structure of the epidermis also forms a highly effective barrier against germs. In addition, cells of the epidermis have the miraculous ability to regenerate, or grow back, unlike many other cells in the body. Epithelial Cells, reproduce

Dermis Reticular Dermis: the deeper and thicker layer of the dermis, which lies above the subcutaneous layer of the skin. It contains dense connective tissue, which includes: Blood Vessels Fibroblasts Mast Cells Nerve Endings Lympathetics Elastic Fibers (interlaced) Collagen Fibers (in parallel layers) Papillary Dermis: most superficial, lies right underneath, made relatively of loose and connective tissue. Capillaries Elastic Fibers Reticular Fibers Collagen

Melanin Definition: a dark brown to black pigment occurring in the hair, skin, and iris of the eye in people and animals. It is responsible for tanning of skin exposed to sunlight. Pigment comes in different shades depending on genetics. Exposure to UV light(sun) will produce more melanin for protection. Melanocyte (cell that produces melanin) size varies in different individuals and may lead to a difference in the amount of melanin produced per cell. 2 Types of Melanin: Eumelanin is the main pigment and is a brownish color. Pheomelanin is associated with red hair and freckles.

Skin Color - Evolutionary Evolutionary Basis Darker skin: natural sunscreen, reflects UV rays Prevent folic acid deficiency Found in areas near the Equator (Ex: Africans) Lighter skin: helped to absorb the limited UV light Needed to produce Vitamin D Found near poles (Ex: Scandinavians, Europeans)

Skin Color - Biological Melanocyte: Cell that produces melanin 2 types: Eumelanin: Dark brown to black Pheomelanin: Red to Yellow More Eumelanin: Darker More Pheomelanin: Lighter Size of extensions dictate the amount of specific melanin released

Steps of Skin Growth

Steps

Questions What is melanin responsible for? Tanning skin exposed to sunlight Protecting skin Producing melonocyte Creating pigment People with lighter skin have more of what type of melanin? Eumelanin Pheomelanin Melanin Dark Melanin What are the two layers of dermis? Papillary and Reticular Epidermis and Papillary Reticular and Melanin Pigment and Hair What is the second lowest cell step in skin growth? Basal Granular Prickle Surface layer What is the purpose of the Epidermis layer? Fight against diseases Provide an outer layer of protection Produce hair Help with scar heeling