BLG 601 Lecture Notes - Lecture 2: Stratum Granulosum, Stratum Spinosum, Stratum Lucidum
Document Summary
Loose connective tissue that connects skin to underlying structures. Avascular nourished by diffusion from capillaries of the papillary layer of the dermis. Composed of cells arranged into layers or strata. Keratinocytes most common; produce keratin for strength: melanocytes contribute to skin color. Same number of melanocytes in all people: melanin produced by these is transferred to keratinocytes. Langerhans cell part of immune system: merkel cells detect light, touch, and superficial pressure. Keratinization as cells move outward through the layers, they fill with keratin, die, and serve as a layer that resists abrasion and forms permeability layer. Stratum basale (germinitivum: deepest portion of epidermis and single layer, high mitotic activity and cells become keratinized. In superficial layers, nucleus and other organelles degenerate and cell dies. Stratum corneum: most superficial and consists of cornified cells. Thick skin: has all 5 epithelial strata. Found in areas subject to pressure or friction. Thin skin: more flexible than thick skin.