5 The Integumentary System Integumentary Basics The INtegumentary System - • integument means "covering" • 1.2-2.2 square meters (16-20 square feet) Part 1 The Skin • 4-5 kg (9-11 lbs) • 7% of total body weight • 1.5-4.0 mm thick • skin = epidermis + dermis epidermis - stratified squamous epithelium dermis - connective, epithelial, smooth muscle, blood, and nervous tissue • I.S. includes nails, hair follicles, sweat glands, and sebaceous glands Integumentary Functions Integumentary Functions 1. protection - acts as a barrier 3. cutaneous sensation chemical barriers - skin secretions and melanin Meissner's corpuscles - light touch physical/mechanical barrier Pacinian corpuscles - deep pressure biological barriers - cells in epidermis, macrophages, DNA free nerve ending - painful stimuli 2. body temperature regulation 4. metabolic functions sweat synthesis of Vitamin D precursor insensible perspiration - routine and unnoticeable (about 5. blood reservoir - about 5% of body's entire blood 0.5 L/daily) volume sensible perspiration - visible output of sweat (up to 12 L or 3 gallons on hot days) 6. excretion - water, salts, small amounts of conservation of heat nitrogenous wastes 1 The integumentary system includes the skin, hair, nails, and certain glands. True False Ping Pong Back & FOrth describing the 6 functions of the integumentary system. 5 The Integumentary System Hypodermis 2 MATA: The skin • a.k.a. subcutaneous layer • not a "real" layer of skin b/c there is no real is our first line of defense against A boundary between dermis and hypodermis infection • functions stores fat, absorbs shock, insulates, anchors skin to B excretes water and salts underlying tissues • structure C helps regulate body temperature loose connective tissue and adipose blood vessels D provides the sensation of touch E absorbs nutrients from the environment Epidermis Can Lucy Grow Spanish Basil? • function - protection • stratum corneum - a.k.a. horny layer excessive water loss, mechanical injury, harmful 20 to 30 layers of dead cells chemicals, keeps pathogens out shed 18 kg (40 lbs) in our lifetime • structure - "Beauty is only skin deep." Hmmm... Can Lucy Grow Spanish Basil? • stratrum lucidum - a.k.a. clear layer thin skin (most of the body) - 4 layers, no L 2 or 3 layers of clear, flat, dead cells thick skin (palms, fingertips, soles of feet) - 5 layers • stratum granulosum - a.k.a. granular layers 3 to 5 cell layers keratinization and water proofing occurs here • stratum spinosum - a.k.a. prickly layer several cell layer thick • stratum basale - a.k.a. basal layer a.k.a. stratum germinativum layer of stem cells continually dividing Feeling lucky?...choose ODD OR EVEN 5 The Integumentary System 2nd Place...What important process takes place in the Keratinization Stratum basale? • cells in the stratum basale are nourished by blood vessels in the dermis • as cells grow and divide they get pushed up and away from their nutrient supply resulting in cell death • older cells harden through the process of keratinization cytoplasm fills with the protein keratin and becomes tough, fibrous, and waterproof • we see dead keratinized cells 1st place...Does all skin have the Stratum lucidum? Explain. Melanocytes & Melanin • melanocytes - cells that produce melanin • melanin - dark pigment that provides skin color 3 MATA: Melanin • melanin function - absorb UV light to prevent DNA mutations and other damaging effects (wrinkles) A makes the skin waterproof B functions as a natural sunblock C provides skin color synthesizes the precursor to vitamin D D E is produced by melanocytes Skin Color Factors that Affect Skin Color • three skin pigments: melanin, carotene, hemoglobin • sunlight, UV sunlamps, X rays • melanin - made by skin (yellow to black) • well oxygenated skin = pink (blush) • type made dependent on genetics P P • low oxygen concentration = bluish (cyanosis) u • melanin is a natural sunblock u l l l • closer to equator, more sun, darker skin l • diet high in yellow vegetables = orange-yellow • closer to poles, less sun, lighter skin • biochemical imbalances • freckles and moles - high conc. of melanin jaundice (liver) = yellowish • all humans have about the same # of melanocytes (melanin producing cells), but the kind and amount produced varies • carotene - produced by certain plants (yellow to orange) • hemoglobin - red blood cells (pinkish) 5 The Integumentary System Dermis 4 Skin color is affected by all of the • function following EXCEPT binds epidermis to underlying tissues sensory reception A diet helps regulate body temperature • structure - 2 layers B sun exposure papillary layer loose connective tissue C chemical imbalances lots of blood vessels to supply itself and epidermis house sensory receptors D genetics dermal papillae help keep skin from tearing reticular layer none of the above (all contribute to dense connective tissue E sweat and oil glands, hair roots skin color) houses sensory receptors and immune system cells blood and lymph vessels Fingerprints Which are you? • a.k.a. dermal papillae (fingerlike) • uneven boundary between the epidermis and dermis • determined by genes BUT, can change as fetus presses against the uterine wall...therefore, identical twins do not necessarily have identical fingerprints P P u u l l l l 5 What layer of the skin is responsible for 6 You have just gotten a paper cut. OUCH! producing fingerprints? It is very painful, but doesn't bleed. Did you cut into the dermis or just the A reticular layer epidermis? B stratum corneum A dermis C papillary layer B epidermis D stratum basale E stratum granulosum 5 The Integumentary System 7 What component of the hypodermis 8 Given that epithelia are avascular, what makes it a shock absorber and layer would you expect to have the insulator? best-nourished cells? A adipose tissue A stratum corneum B loose connective tissue B stratum granulosum C abundant blood vessels C stratum spinosum D dense connective tissue D stratum basale Nails The Integumentary System - • function Part 2 protective covering on the ends of fingers and toes Appendages & Imbalances • structure > nail matrix - responsible for nail growth > lunula - whitish, thickened, half-moon over the matrix > cuticle (eponychium) - skin folds over nail > hyponychium - beneath free edge where dirt and debris collect Hair Follicles • protects against insect bites/stings, heat loss, sunlight, keeps bugs/lint out of nose and eyes • hair covers the whole body EXCEPT for the palms, soles, lips, nipples, and parts of external genitalia • hair (pili)= dead, keratinized epidermal cells that originate in a hair follicle (dermis) > root - undergoing keratinization > shaft - keratinization complete – medulla - middle – cortex - pigment – cuticle - outside 5 The Integumentary System Hair Color • determined by genes that direct the type and amount of pigment melanocytes produce *oil gland lots of melanin = dark intermediate = blonde to brown no pigment = white *smooth muscle that trichosiderin = red causes hairs to "stand" up mix of pigment and no pigment = grey *provide nutrients & signal hairs to grow High Card Wins...Best 2 out of 3 WInner...Review the parts of a nail. RIGHT LEFT Non-winner...Review what you know about Hair. 1 Hair and nails function as a A protective barrier B site for melanin production C oil producer D personal embellishment 5 The Integumentary System Sweat Glands 2 Which of the following does NOT • a.k.a. sudoriferous glands • over 3 million per person describe hair? • found all over the body except nipples and parts of external genitalia A • eccrine sweat glands dead and keratinized > abundant on palms, soles, forehead > 99% water, some salts, vitamin C, antibodies, dermicidin B color determine by your genes (microbe-killing protein), some waste > acidic - pH between 4 and 6 C originates in dermis > prevents overheating • apocrine sweat glands D medulla contains pigment > confined to axillary and anogenital areas > sweat + fatty substances and proteins > when broken down by bacteria on skin's surface produces body odor > begin functioning at puberty; function not fully known (possible sexual scent gland) Sebaceous Glands • a.k.a. oil glands • only found in thin skin • small on trunk and limbs • large on face, neck, and upper chest • produce sebum, an oily substance that keeps hair soft, pliable, and waterproof • sebum forced out by arrector pili contractions • clogged glands causes acne *temp control *body odor Ping pong back and forth describing sweat and sebaceous glands. 3 Which of the following is FALSE? Some sweat glands help with A thermoregulation. Some sweat glands produce an fatty B substance that contributes to body odor. Sebaceous glands are associated C with an eponychium. Clogged sebaceous glands can D cause acne. 5 The Integumentary System Degrees of Severity What is a burn? first degree superficial burn • tissue damage inflicted by intense heat, electricity, epidermis intact and radiation, or certain chemicals functioning properly • immediate threat to life - loss of body fluids resulting in dehydration and electrolyte imbalance second degree • delayed threat - infection partial-thickness burn • categorized as first, second, or third degree damage extends into dermis; most painful blisters w/o epidermis victims begin to lose fluids, heat, and the ability to block infection third degree full-thickness burn both dermis and epidermis destroyed nerve ending destroyed; NO feeling of pain *Graphic Images on next slide lose fluid, heat, and ability to block infection Rule of Nines - 11 Body Regions • approximates extent of burns 4 A burn that is not painful would be • body divided into 11 areas each representing 9% classified as of surface area (genitals 1%) > head > right arm A first degree > left arm > chest B second degree > abdomen C > upper back third degree > lower back D fourth degree > right thigh > left thigh > right leg (below the knee) > left leg (below the knee) 5 Which of the following is TRUE? Infection is the number one concern A for burn victims. The rule of nines helps approximate B the extent of burn damage. A sunburn is typically considered a C second-degree burn. Second-degree burns are also D called full-thickness burns..