FunctionProtects deeper tissue from:
~ Mechanical damage (bumps) ~ Chemical Damage (acids and bases) ~ Bacterial Damage ~ Ultraviolet radiation (damaging effects of sunlight) ~ Thermal (heat or cold) damage ~Desication (drying out) Aids in body heat loss or heat retention (controlled by the nervous system) Aids in excretion of urea and uric acid Synthesizes vitamin D |
How accomplishedPhysical barrier contains keratin, which toughens cells; fat cells to cushion blows; and pressure receptors, which alert the nervous system to possible damage. Has relatively impermeable keratinized cells; containes pain receptors, which alert the nervous system to possible damage. Has an unbroken surface and "acid mantle" (skin secretions are acidic, and thus inhibit bacteria). Phagocytes ingest foreign substances and pathogens, preventing them from penetrating into deeper body tissue. Melanin produced by melanocytes offers protection from UV damage Contains heat/cold/pain receptors. Contains a waterproofing glycolipid and keratin. Heat loss: By activating sweat glands and by allowing blood to flush into skin capillary beds so that heat can radiate from the skin surface. Heat retention: By not allowing blood to flush into skin capillary beds. Contained in perspiration produced by sweat glands. Modified choleterol moecules in skin converted to vitamin D by sunlight. |
By: Miranda Lewis