Integumentary System Skin cc: chexee - N00.
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Transcript of Integumentary System Skin cc: chexee - N00.
Integumentary SystemSkin
cc: chexee - https://www.flickr.com/photos/61923475@N00
Skin• surface area of 1.2-2.2 square
meters• weighs 9-11 lbs• 7% of total body weight
cc: Chris Nuzzaco - https://www.flickr.com/photos/46925679@N04
Functions of Skin1. 3 types of barriers2. Chemical, Physical, Biological
cc: Yomie - https://www.flickr.com/photos/22743502@N05
Chemical1. skin secretions2. melanin
cc: euthman - https://www.flickr.com/photos/78147607@N00
Skin Secretions1. Acid mantle2. Sebum3. Human defensin4. Cathelicidins
cc: † David Gunter - https://www.flickr.com/photos/23812004@N03
Melanin1. Provides a chemical pigment
shield to protect from UV damage
cc: @Doug88888 - https://www.flickr.com/photos/29468339@N02
Physical1. continuity of skin2. hardness of the keratinized cells3. If too thick, lose suppleness and
agility4. If too thin, not as protective5. Waterproofing glycolipids
cc: GrungeTextures - https://www.flickr.com/photos/44718043@N06
Physical1. Lipid soluble items can penetrate2. oxygen, carbon dioxide, fat-soluble
vitamins, steroids3. certain plant chemicals (poison oak and
poison ivy)4. organic solvents (acetone, dry-cleaning
fluid, paint thinner5. salts of heavy metals (lead and mercury), &
drug agents
cc: ntr23 - https://www.flickr.com/photos/65919269@N00
Biological Barriers1. Langerhans' Cells2. active elements of the immune system3. for immune response to be activated,
the antigens must be presented to lymphocytes (WBCs)
4. the Langerhans' cells play this role in the epidermis
cc: @Doug88888 - https://www.flickr.com/photos/29468339@N02
Biological Barriers1. Macrophages in the dermis2. DNA molecules3. electrons absorb radiation and
transfer it to the nuclei, which heat up and vibrate to dissipate heat to surrounding water molecules
cc: kevin dooley - https://www.flickr.com/photos/12836528@N00
Other Functions
cc: vestman - https://www.flickr.com/photos/61417318@N00
Body Temperature• regulates temperature within
homeostatic limits• as long as air is cooler than
internal temperature, the skin surface loses heat to the cooler objects in its environment
cc: Leo Reynolds - https://www.flickr.com/photos/49968232@N00
Body Temperature• Sweat continuously, just
unnoticeable• when body temp rises, so does
sweat production• can lose up to 12L of water per day• evaporation of sweat cools the body
to prevent overheating
cc: joshuaseye - https://www.flickr.com/photos/27279494@N05
Body Temperature• when the external environment is
cold, blood vessels constrict, this causes the warm blood to bypass the skin temporarily
• this slows passive heat loss, to conserve heat within the body
cc: salendron - https://www.flickr.com/photos/8681074@N03
Cutaneous Sensation• richly supplied with cutaneous
sensory receptors (part of the nervous system)
• Meissner's corpuscles• Merkel discs• Pacinian corpuscles• Hair Follicle Receptors
cc: pfarrell95 - https://www.flickr.com/photos/65005341@N03
Merkel’s Disc
Metabolic Functions•When sunlight bombards the skin, modified
cholesterol molecules circulating through blood vessels in the dermal layer are converted to a vitamin D precursor• These are transported via the blood to
other body areas to play various roles in calcium metabolism•Calcium cannot be absorbed from the
digestive tract without vitamin D
Blood Reservoir•Can hold large volumes of blood within the
dermal layer•About 5% of the body’s entire blood volume•When other organs need a greater blood
supply, the dermal vessels constrict, restricting the blood flow to the skin and shunting it to the needed areas
Excretion• Limited amounts of nitrogen-containing
wastes are eliminated though sweat (although most are excreted through urine)•Profuse sweating is an important avenue for
water and salt loss