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| Functions of the Integumentary System |
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Definition
Protection - barrier against pathogens, chemicals, radition, and physical damage Prevents dehydration - water is neither absorbed or lost through skin Sensation - nerves near the skin surface detect heat, cold, pressure, touch, and pain Vitamin D - First step of vitD synthesis from cholesterol occurs in skin Waste removal - urea, ammonia, and uric acid are secreted with sweat Regulates temperature - vasoconstriction, vasodilation, and sweat |
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| Vasodilation in the Integumentary System |
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Definition
| Dilation of blood vessels near skin surface increases blood flow and allows excess body heat to escape |
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| Vasoconstriction in the Integumentary System |
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| Constriction of the blood vessels near the skin surface slows blood flow and retains body heat |
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| Basal surface of the epidermis. Stem cells are actively dividing and differentiating into keratinocytes to replace those lost to exfoliation. Keratinocytes, melanocytes, stem cells, and tactile cells are found here. |
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| Found above stratum basale in the epidermis. Made of several layers of keratinocytes. Thickest layer of the skin (accept in thick skin). Lower cells in this layer are still capable of mitosis, but give way to keratin production further up. Cells look cuboidal toward the bottom and become flatter toward the top. |
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| Found above stratum spinosum in the epidermis. Three to five layers of squamous keratinocytes (more in thick skin). This layer contains keratohyalin granules. |
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| Found above stratum granulosum in the epidermis (thick skin only). Packed with the kerotin intermediary eleidin. The cells have no organelles and no nuclei. |
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| Apical layer of epidermis. Consists of the dead, keratinized cells. Provides durable protection. |
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| Found between stratum spinosum and stratum granulosum. Made of tight junctions between cells, secreted lipids, and insoluble proteins in the plasma membrane. Prevents water loss but also cuts off the layers above it from nutrients. |
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| The majority of epidermals cells. Produces lots of keratin. |
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| Macropahes that are found in the stratum spinosum and stratum granulosum of the epidermis. They stand guard against toxins, microbes, and other pathogens; activating the immune system so the body can defend itself. |
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| Found in the stratum basale of the epidermis. They are receptors for the sense of touch, and as such, are associated with an underlying dermal nerve fiber. |
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| A tactile cell and its associated nerve fiber. |
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| Cells that produce and exocytose melanin (skin pigment). Keratinocytes then endocytose the melanin and create a layer over the nucleus that protects DNA from UV radiation. |
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| Contributes to skin color and used to protect DNA from UV damage. Skin color is determined by how much melanin the melanocytes make, how quickly it's made, and how long the melanin lasts; note that the number of melanocytes is similar in any race and is not a factor for skin color. |
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| Connective tissue layer beneath epidermis. Contains sweat sebaceous glands, hair follicles, and the blood vessels and nerves that serve the epidermis. |
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Papillary Layer - Layer just below epidermis that consists of areolar connective tissue. Its loose consistency allows macrophages and leukocytes to patrol the tissue. Reticular Layer - Much thicker layer of dense irregular connective tissue. |
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| Upheavals of the dermis' papillary layer that help prevent sliding of the epidermis across the dermis, produce friction ridges (fingerprints), and allow blood vessels and nerves to get close to the surface. |
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| Blue skin color that is a sign of low amounts of O2 in the blood. Could be a sign of a respiratory problem or from long term exposer to cold temperatures. |
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| Reddening of the skin. Caused by vasodialation due to heat or emotion (blushing). |
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| Whitening of the skin. Caused by vasoconstriction due to stress, shock, cold, or anemia. |
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| Yellowing of the skin. Caused by a build up of bilirubin; could be a sign of rapid erythrocyte breakdown due to disease; cancer, hepatitis, cirrhosis, or other diseases that could interupt normal liver function; or, in the case of infants, bilirubin can build up because the liver is not yet fully developed. |
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| One of the products that results from the liver's breakdown of hemoglobin. If it accumulates it can cause jaundice. |
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| Also called subcutaneous tissue, or superficial fascia. The hypodermis binds the skin to the underlying muscle (as well as other tissues) and pads the body. Consists of areolar connective tissue and adipose tissue. Called subcutaneous fat when predominantly adipose tissue. |
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Hair shaft - section of hair above the surface of the skin. Cells are dead and keratinized. Hair root - part of the hair that is in the skin. Cells are dead and keratinized. Hair bulb - deepest part of the hair. Within the bulb is the hair matrix, the still living cells that divide and push older cells upward. Hair receptor - Nerves around the hair follicle that detect movement of the hair. Piloerector muscle - smooth muscle that makes the hair stand up and makes "goosebumps" on skin in response to cold and fear. |
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Insulation - the hair of the scalp is thick enough to keep in body heat. Protection - Keeps sweat out of the eyes; prevents particles and organisms from entering the ear, nose, and eye. Movement of the hair by parasites (fleas, lice) alerts the person their presence. Social - recognition of sexes and sexual maturity. |
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Made of dead cells packed with parallel keratin fibers. Nail matrix - epithelial cells that undergoe mitosis to produce the nail. Found beneath the back end of the nail. Nail plate - visible, hard, keratinized portion of the nail. Nail bed - skin underneath the nail. |
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Protection of the sensitive ends of fingers/toes. As tools for digging, picking, scratching. |
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| Holocrine glands connected to hair follicles that produce oily sebum. Keeps skin and hair from drying out and protects against bacteria and fungi. |
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| Sudoriferous glands that are associated with a hair follicle in the axilla, groin, and mature male beard. They secrete a thicker sweat that contains more fatty acids than merocrine sweat glands. Secretes in response to stress and sexual stimulation. |
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| Sudoriferous glands that are found all over the skin; especially on the forehead, palms, and soles. Mostly water with salts, urea, ammonia, etc. Low pH (4-6) inhibits bacteria and fungi growth. Secretes in response to increased body temperature and stress. Can cool the body, prevent infection, and dispose of wastes. |
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1) Blood clots and holds wound together. A scab forms on the surface to protect the opening. 2) Macrophages phagocytize cellular debris, etc, and activate the immune system. Mast cells release histamine which increases blood flow. 3) Epidermis repairs itself by regeneration - the replacement of damaged cells by mitosis. 4) Dermis repairs itself by fibrosis - the replacement of damaged tissue with scar tissue (mostly collagen) made by fibroblasts. Scar tissue holds an organ together but does not restore normal function. |
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| Involve only the epidermis. Heals by regeneration of the epidermis in days with no scarring. Symptoms include redness, slight edema (swelling), and pain. |
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| Involves the epidermis and some of the dermis. The epidermis heals by regeneration (using epithelial cells from hair follicles, glands, and surrounding tissue). The Dermis heals by fibrosis, taking weeks or months, and may scar. Signs include red, white, or tan color, edema (swelling), blistering, and pain. |
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| Involve the full thickness of the skin. Destroys epidermis and dermis, including everything in between. There is a risk for fluid loss, infection, and the toxic effects of eschar (burned, dead tissue). Healed using skin grafts and usually scar. |
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| Cancer arising from the stratum basale of the epidermis. It is the most common type of skin cancer and also the least dangerous, because it seldom metastasizes. Usually found in people 60+. Good chances of recovery when found early. |
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| Cancer arising from keratinocytes in the stratum spinosum of the epidermis. Good chances of recovery if found early. If left untreated it often metastasizes to the lymph nodes and can be lethal. Usually found in older people. |
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Cancer of the melanocytes, often the melanocytes of a preexisting mole. Metastasizes quickly and is often fatal if untreated. Use ABCD to spot: Asymmetry, Border (irregular), Color (mixed), Diameter (>6mm). |
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| Heat-Related Disorders Occur... |
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Definition
| When conditions prevent sweat from adequately cooling the body. Can result from overexertion or from humidity preventing evaporation of sweat. |
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Loss of water and salt that usually occurs from exertion in a hot environment. Symptoms - fatigue, nausea, dizziness, fainting, sweating, cool and clammy skin. Treatment - rest in a cool place, replacement of water and salts. |
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A body temperature over 104°F. Can be fatal. Symptoms - dizziness, disorientation, nausea, convulsions, coma, hot and dry skin. Treatment - immediate medical care is needed. Person is cooled under medical supervision. |
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