BIOL 2130 Lecture Notes - Lecture 16: Metabolic Waste, Sebaceous Gland, Lubricant
Document Summary
Melanocytes are mostly in the stratum basale. Melanin accumulates in membrane-bound granules called melanosomes. Amount of melanin produced depends upon genetics and exposure to sunlight. Epidermal dendritic cells: alert and activate immune cells to a threat (bacterial or viral invasion) Merkel cells: associated with sensory nerve endings, serve as touch receptors called merkel discs. Two layers: papillary layer (upper dermal region) Others house pain receptors (free nerve endings) and touch receptors. Fingerprints are identifying films of sweat: reticular layer (deepest skin layer) Overall dermis structure: collagen and elastic fibers located throughout the dermis. Elastic fibers give skin elasticity: blood vessels play a role in body temperature regulation, nerve supply sends messages to the central nervous system. Three pigments contribute to skin color: melanin. Yellow, reddish brown, or black pigments: carotene. Orange-yellow pigment from some vegetables: hemoglobin. Red coloring from blood cells in dermal capillaries. Oxygen content determines the extent of red coloring.
