BIOL 2500 Lecture Notes - Subcutaneous Tissue, Hair Loss, Melanin
Document Summary
Skin: bodys biggest organ, surface area ~ 20 square feet, number of cells lost/minute: 40000 50000, ~9 lbs of cells every year found in cell skin renews every~35 days: byy the time you"re 20, your skin has been replaced. Water: regulates body temperature, makes vitamin d, excretes waste, sensory lots of sensory receptors regions of the skin, epidermis (cutaneous membrane/skin, dermis (cutaneous membrane/skin, hypodermis (superficial fascia) not technically part of the skin cells of the epidermis, keratinocytes produce keratin (tough protein, melanocytes make pigment melanin (skin color, uv protection, dendritic cells immune function, tactile cells sensory receptors for touch epidermis. Basale layer deepest layer single layer of cuboidal or columnar epithelial cells actively mitotic daughter cells pushed up into stratum spinosum: most destined to become keratinocytes some migrate into dermis to form epidermal derivatives (hair, nails, and glands) also contain melanocytes (10 25%, stratum spinosum.
