Integumentary systemTwo Layers of the Dermis:1. Papillary layer Upper dermis Has ridges that protrude up into the epidermis called the dermal papillae It is composed of loose connective tissue
Integumentary systemFunctions of Dermal papillae:•Increased blood flow to epidermis•Increased surface area for dermisand epidermis to connect to eachother to hold it strongly together
Integumentary systemFunctions of Dermal papillae:•Contains sensory touch receptors•Keeps skin from tearing•Aids in gripping•Gives you finger prints
Integumentary systemLayers of the dermis:1. Papillary layer2.Reticular layer Lower dermis Further keeps from tearing Contains deep pressure sensors Contains sweat glands, lymph vessels, smooth muscle, and hair follicles
Integumentary systemLayers of the dermis:1. Papillary layer2. Reticular layer Made of dense irregular connective tissue Has criss-cross collagen fibers that give it a strong elastic network This forms lines of cleavage or Langer’s Lines or Line of tension
Langer’s LinesNote: Incisionsparallel to theLanger’s Lineswill heal fasterand with lessscarring.
Integumentary systemHypodermisMade of adipose tissue to insulateand loose connective tissueFunctions to: 1.Conserve heat 2.Connects skin to layer below 3.Contains blood, lymph, base of hair follicles and sweat glands 4. Stores lipids and cushions the body
Integumentary systemHypodermisFunctions to: Hypodermis is 8% thicker in females than males
Integumentary systemHypodermis Also known as the subcutaneous tissue Where medical personal will give a subcutaneous injection because of the rich blood supply
Integumentary systemBlister – a separation between theepidermis and the dermisBurn - destruction of the differentlayers of the skin and the structureswithin the skin.The severity of the burn is dependentupon the depth of the damage.
Integumentary systemThree Classifications of burns:1. First degree or 1 is when there has been some damage to the epidermis
Integumentary systemThree Classifications of burns:2. Second degree or 2 is when the epidermis is completely destroyed and there is some damage to the dermis
Integumentary systemThree Classifications of burns:2. Second degreeNote: New epidermis will be regenerated from the cells surrounding the hair follicles. The hair follicles are lined with epidermal cells non-keratinized.
Integumentary systemThree Classifications of burns:3. Third degree or 3 is when the epidermis and dermis are completely destroyed and there isdamage tothehypodermis.Must have a skin graft to heal.
Integumentary systemLayers of the epidermis:composed of 4-5 layers depending onthe region of skin being consideredThose layers in descending order arethe stratum corneum, stratum lucidum,stratum granulosum, stratumspinosum, and stratum basale.
Integumentary systemLayers of the epidermis:1. Stratum basale also referred to as "basal cell layer” is the deepest layer Single layer ofcuboidal/columnar cells that undergoes rapid mitosis
Integumentary systemLayers of the epidermis:1. Stratum basale Cells migrate upward from here and begin to differentiate Also known as the stratum germinativum
Integumentary systemLayers of the epidermis:2. Stratum spinosum is several cell layers thick Carries out mitosis as well Some cells produce Keratin
Integumentary systemLayers of the epidermis:3. Stratum granulosum flat cells (squamous) Layer where keratinization begins cells overproduce the protein keratin and smother themselves cells in this layer are beginning to die
Integumentary systemLayers of the epidermis:4. Stratum lucidum found only in the thick skin of the palms of the hand and soles of the feet cells in this layer are dead three to four strata (layers) thick Helps protect against UV rays
Integumentary systemLayers of the epidermis:5. Stratum corneumoutermost layer of squamous cellscells filled with keratindead cells that have migrated up fromthe stratum granulosum is true protective layer of skin is 25 – 30 cell layers thick
Integumentary systemLayers of the epidermis:5. Stratum corneumthese dead cells slough off and arecontinuously replaced by new cellsthe sloughing off ofcells is known as desquamation
Integumentary systemLayers of the epidermis:5. Stratum corneumJust for your additional information:In the human forearm, for example,about 1300 cells/cm2/hr are shed andcommonly accumulate as house dustDesquamation – term in Latin forscaling a fish
Integumentary system MelaninIs a brown pigment found in the skin andhairprimary determinant of skin colorproduced by melanocytes in the stratumbasalethrough phagocytosis vesicles of melaninwill enter cells of stratum basale andspinosum
Integumentary system MelaninNote: The concentration ofmelanocytes in the skin of people isabout the same, but some don’tproduce as much melanin due togenetics.UV light willtrigger melanin production
Integumentary system MelaninSome individual animals and humanshave very little or no melanin in theirbodies, a condition known as albinism.There are a number of different typesof melanin giving different colors ofskin (ex. Eumelanin most common) andhair plus other pigments.
Integumentary system Skin CancersThere are three main types of skincancer:1. Malignant melanoma• cancer cells are found in the melanocytes• characterized by uncontrolled mitosis of melanocytes in the stratum basale
Integumentary system Skin CancersThere are three main types of skin cancer:1. Malignant melanoma usually occurs in adults is the rarest, but worst form of skin cancer has the highest death rate and is responsible for 75 percent of all deaths from skin cancer Usually in fair-skinned people
Integumentary system Skin CancersThere are three main types of skin cancer:1. Malignant melanoma2. Squamous cell carcinomauncontrolled mitosis of cell of thestratum spinosumNot as dangerous as melanoma, butmore dangerous than basal cellcarcinoma
Integumentary system Skin CancersThere are three main types of skin cancer:1. Malignant melanoma2. Squamous cell carcinoma95% cure rate when properly treatedmay appear as nodules, or as red,scaly patches of skin second most common skin cancer found in fair skinned individuals
Integumentary system Skin CancersThere are three main types of skin cancer:1. Malignant melanoma2. Squamous cell carcinoma3. Basal cell carcinomaUncontrolled mitosis of stratumbasale layer cellsusually appears as a small, fleshybump or nodule on the head, neck, orhands
Integumentary system Skin CancersThere are three main types of skin cancer:1. Malignant melanoma2. Squamous cell carcinoma3. Basal cell carcinomaeasily detected and has an excellentsuccessful treatment, when properlytreatedis the most common skin cancer, butmost treatablefound in fair-skinned individuals
Integumentary system Skin CancersMyth: Darker skinned people can’tget skin cancer.The darker the skin the less likely,but the more fatal.Usually melanoma the worst kind.Usually late diagnosis or diagnosedincorrectly
Integumentary system Skin CancersMyth: Darker skinned people can’t get skin cancer. almost always arise on the sole of thefoot, palms, fingers, toes, under thenails and mucosal surfaces like in themouth
Integumentary system Hair Follicle part of the skin that grows hair bypacking old cells togetherCover entire body except eyelids,palms, soles, and lips Attached to the hair follicle is asebaceous gland (oil gland)
Integumentary system Hair FollicleThe thicker density of hair, the moresebaceous glands are found•Also attached to the follicle is a tinybundle of muscle fiber called thearrector pili that cause hair to stand upand a goose bump.
Integumentary system Hair Follicle has two parts based on location: 1. Shaft – protrudes from the skin 2. Root – imbedded beneath the skin At the base of the root is the hair bulb
Integumentary system Hair has no nervesComposed of hair structure and hairfollicleHas a protective function
Integumentary system Hair Strand has three layers:1. Medulla center layer that is 2-3 cell layers thick Composed of soft keratin (less sulfur) and air
Integumentary system Hair Strand has three layers:2. Cortex middle layer Composed of many cell layers Is hard keratin (contains more sulfur) Makes up most of hair strand contains melanin and maybe red hair pigments
2. CortexHair color:• melanin is produced and throughphagocytosis it is incorporated into cellsof cortex •the more melanin the darker the hair color •red hair also contains a red pigment, the more melanin the darker the red •gray hair lacks melanin at all
Integumentary system Hair Strand has three layers:3. Cuticle outer most layer of hard keratin One cell layer thick, but cells overlap like shingles on the roof
Integumentary systemHair Follicle layers:1. Internal epithelial root sheath2. External epithelial root sheathTwo layers are covered by dermal root sheathHair bulb – expanded end of follicle
Integumentary system Hair FolliclePapilla – extends into the bulb and provides nutrients
Integumentary system Hair FollicleHair matrix Is at the base of the hair bulb Where cell mitosis/reproduction occurs Cells are undifferentiated (all look the same) Hair electrolysis damages the cell in the matrix cells don’t reproduce
Integumentary system Hair GrowthNot all hair grows at the same rateEyelashes/brows vs. hair on headHair grow and then stops
Integumentary system Hair GrowthThree stages of hair growth:1. Anagen a growth phase when hair is growing in length Eyelids – spend 30 days in this phase Head strand of hair spends 3 – 7 years in this phase 90% of head hair is in this phase
Integumentary system Hair GrowthThree stages of hair growth:1. Anagen2. Catagen Hair stops growing; transition phase Club hair or replacement hair is formed Head hair spend 2-3 weeks in this phase
Integumentary system Hair GrowthThree stages of hair growth:1. Anagen2. Catagen3. Telogen Resting phase – 10% of hair on head is in this phase head hair spends about 100 days in this phase, eyelids 9 months Hair falls out You lose about 100 hairs on your head per day
Integumentary system NailsFunctions: protections reinforce the finger/toe tips
Integumentary system Nails Parts of the NailoNail body – the part that is visibleoNail root – extends underneath theskinoNail matrix – part of nail root wherecells reproduce. Cells differentiate andfill with keratinoLunula – upper part of the nail matrix,is thicker and appears white
Integumentary system Nails Parts of the NailoNail bed – thick epithelial tissue thatthe nail rest onoFree edge – part that sticks out pastthe digitoCuticle – fold of skin on proximal end
Integumentary system NailsGrow constantly – no growth andresting phasesGrow at a rate of about 3 mm a month
Integumentary system GlandsTwo types based on what they secrete:1. Sweat – water and electrolytes, sweat2. Sebaceous - oil
Integumentary system GlandsTwo types of sweat glands:A. Merocrine Found all over skin, heaviest in soles of feet and palms of hands Secrete a clear liquid to surface of skin Are a merocrine gland
Integumentary system GlandsTwo types of sweat glands:A. Merocrine Regulates body temperature Smaller and more numerous than apocrine sweat glands Don’t secrete into hair follicle
Integumentary system GlandsTwo types of sweat glands:B. Apocrine glands Found armpits, groin and nipples Secrete a milky substance; odorous Actually merocrine glands, but were once thought apocrine Secrete into hair follicle Found deeper in skin than merocrine
Integumentary system GlandsTwo types based on what they secrete:1. Sweat – water and electrolytes, sweat2. Sebaceous - oilSebaceous glandsSecrete an oily matter called sebuminto hair folliclesPore = opening of hair follicle to allowoil to lubricate the skinHolocrine glandsOverproduction of sebum = acne