Skin System

icer215's version from 2016-08-20 01:34


Question Answer
Too coldhair stands up (goose bumps), vasoconstriction decreases blood supply at skin (less heat loss).
Too hotsweat (evaporative cooling), vasodilation increases blood supply at skin (more heat loss).
Water homeostasis Insulates body against water loss.
Osmoregulationsweat excretes salts and nitrogenous wastes (urea, uric acid, ammonia)
functions of the skinprotect against UV radiation by making melanin (absorbs UV) make vitamin D upon exposure to sunlight. Act as blood reservoir. Vasoconstriction in skin shunts blood to other organs. Sense touch, pressure, pain, heat, cold. Protection.
hair, erectile musculaturehairs help insulate the body by trapping air in them. Normally hair lies at an angle to the skin, with erectile muscle attaching to it. When it's cold, erectile muscles contract, and the hair stands up. This erect position helps hair to trap more air, providing better insulation.
fat layer for insulationfat in hypodermis act as insulation.
sweat glands, location in dermisproduce sweat, cools the body by evaporative cooling.
Vasoconstrictionreduces blood supply to reduce heat loss at the surface of skin
Vasodilationincrease blood supply to increase heat loss at the surface of skin


Question Answer
nail hard keratin = tougher than the soft keratin on skin.
callusesextra thick layer of dead keratin-packed cells on the surface of skin.
hair hard keratin
protection against abrasion, disease organismsKeratin protect skin against abrasion. The tight seal made from keratin-packed cells and glycolipids form a barrier against pathogens.
Chemical protectionSweat is acidic, contains antibodies, and antimicrobial agents. Sebum (skin oil) kills bacteria.
Natural floragood bacteria on the surface of skin don't cause harm to you, and they fight off bad bacteria that can harm you.
Epidermis stratified squamous epithelial tissue = protection
Keratinocytes cells that produce keratin = dominates the epidermis. normal cells at the bottom of the epidermis, but gets flatter as you go up, and becomes dead, keratin plates at the surface of the skin.
Melanocytescells that make melanin, the skin pigment.


Question Answer
Dendritic cells (Langerhans cells)phagocytes that eat pathogen and present foreign antigens to activate immune response.
Dermis connective tissue = blood, nerve supply
Fibroblasts make fiber and ground substance (glue) for the extracellular matrix that makes up connective tissue.
Hypodermis adipose tissue = absorbs shock and provides insulation
Hormones that stimulate vasoconstriction includeAcetylcholine, Epinephrine, Norepinephrine, Dopamine, Antidiuretic hormone (ADH)
Keratin is water insoluble, and layers of dead, keratin-packed cells reside on the skin surface.
Glycolipids seal the space between the dead keratin-packed cells.
Sebum(skin oil) contribute some. But oil glands are not present everywhere (absent in palms and soles).
Apocrine sudoriferousglands produce oily sweats (more viscous/thick than watery sweats produced by Eccrine sudoriferous glandsà found in armpits
Acetylcholine actson the Eccrine sudoriferous glands and adrenaline acts on both Eccrine and apocrine sudoriferous glands.Acts on glands under stress, fear, pain, anxiety
Androgens (testosterones)regulate the apocrine sudoriferous glands