 Actually, many resources call the skin the largest organ of the body

 Made up of: Skin and it’s Appendages  Hair  Nails  Sebaceous Glands (oil)  Sudoriferous Glands (sweat)

 Protection From invasion of pathogens  Sensory perception Nerve receptors

 Temperature regulation  Heat regulation  Storage of fat  Protection of muscles, bones and organs underneath  Absorption ~medication patches  Excretion ~sweat

 The integumentary system includes three layers Epidermis Dermis Subcutaneous

 Avascular, outermost covering  Epidermal cells  Five sub layers  Stratum germinativum  Papillae – fingerprints  Stratum spinosum  Stratum granulosum  Statum lucidum  Soles of the feet, palms of the hands  Stratum corneum

 Keratinocytes  Produce keratin  dry, waterproof  Merkel cells  Sensory receptors  touch  Melanocytes  Make the protein melanin  Protects against UV rays of sun  Langerhans cells  Macrophages, defend against microorganisms

 Three pigments contribute to skin color: Melanocytes  Pheomelanin ---red to yellow in color  light skin  Eumelanin --- dark brown to black  dark skin Carotene  Yellow to orange pigment  Asians Hemoglobin (red blood cells/oxygen)  Gives some fair skinned people a pinkish color Albino  Lack of melanin

 Alterations in skin color may indicate disease conditions or emotional states Erythemia – Redness – dilation of capillaries  Fever, allergic reaction, inflammation or embarrassment Cyanosis – Bluish or grayish tint – degrease in oxygen in capillary network  Heart or respiratory disease Jaundice – Yellow – accumulation of bile in capillary network  Gallbladder or liver disease Pallor – constriction of capillary network or decrease in red blood cells  Emotional stress or anemia

Erythemia

 Cyanosis

 Jaundice

 Pallor

 Albino

 “True skin”  Connective tissue  Vascular, blood vessels  Many nerve receptors  Appendages of the skin Sweat glands (sudoriferous glands) Oil glands (Sebaceous glands) Hair structures

 Composed of Dense connective tissue Collagen tissue bands Numerous blood vessels Muscle fibers Mast cells – respond to injury, infection or allergy; produce histomine White blood cells Oil glands Fat glands Fat cells

 Also called hypodermal layer  Lies under the dermis  Not a true part of the integumentary system  Attaches integumentary system to the surface muscles underneath  Contains ½ the body’s stored fat

 Hair: Hair protects the skin Composed of  Outer cuticle layer – Cortex (Hair Pigment/Color)  Inner layer – Medulla  Root – part implanted in the skin surface (hair follicle)  Shaft – projected from the skin surface

 Shape of hair follicle determines Round Follicle – Straight Oval Follicle – Wavy Flat Follicle – Curly  Alopecia Genetic predisposition in some people Permanent hair loss

Attached to each hair follicle When chilled the muscle contracts  goosebumps

 Hard structures at the ends of the fingers and toes - protection  Formed in nail bed/matrix If a nail is lost due to injury or illness it will always grow back as long as the nail bed is intact

 Healthy nails – pink and grow 1mm/wk Fingernails grow faster than toenails Aging slows growth  Nails can reveal Health or Disease ConditionNail color Liver diseaseWhite nails Kidney diseaseHalf of nail is pink, half is white Heart conditionNail bed is red Lung diseaseYellow and thickening of nails AnemiaPale nail bed DiabetesYellowish with slight blush at the base Hypoxia (low oxygen)Bluish in color

 Sweat glands Coiled tubes that go through the dermis and open on the surface of the skin in pores Large #’s under arms, palms, soles, foreheads Produce perspiration 99% water, salts and wastes Water Loss from skin  500 ml/day  Needs to be replaced

 Oil glands Secrete Sebum – thick, oily substance Protects/lubricates skin O pen on hair follicles When plugged/clogged pimples form