Presentation on theme: "The Integumentary System"— Presentation transcript:
1 The Integumentary System Mr. WestAnatomy and Physiology
2 What are the primary functions of the Integumentary System? Protection: provides 3 types of barriersChemical barriers: low pH of skin secretions slows bacterial growth. Human defensin is an antibiotic that destroys bacteria (produced by human skin)
3 Physical barriersPhysical barriers: very few substance are able to enter the skin. Substances able to pass.Lipid-soluble substances: oxygen, carbon dioxide, some vitaminsOleoresins- poisons (poison ivy)Organic solvents- dry-cleaning fluid, paint thinnerSalts of heavy metals- lead, mercury, nickelPenetration enhancers- drug agents that help substances into the body.
4 Biological barriersLangerhans’ cells- act as macrophages police the epidermis for viruses and bacteria.
6 Functions cont.Thermoregulation- skin contains sweat glands that secrete watery fluid, that when evaporated, cools the body.Sensation- Skin contains sensory receptors that detect cold, touch, and pain.Vitamin D synthesis- cholesterol in the skin is bombarded by sunlight and converted to vitamin D (calcium cannot be absorbed from digestive tract)
7 Functions cont.Blood reservoir- blood will be moved from skin to muscles during strenuous activity.Excretion- Sweating is an important outlet for wastes such as salt and nitrogen containing compounds. (urine)
8 Why is Skin Important? Regulates Body Temperature – What happens when it is hot?– What happens when it is cold?• Sense Organ– Why is sense important in the skin?• Protective Layer for Everything Underneath– Protects body from physical, chemical andmicrobial damage
10 What are the major characteristics of the skin? Waterproof, stretchable,washable, and permanent-press, that automatically repairs small cuts, rips and burns and is guaranteed to last a lifetime.Surface area of up to 2.2 square meters11 pounds7% of total body weightPliable yet tough
11 What are the 3 major layers of the skin? Epidermis (epi-upon)Composed of epithelial tissue (stratified squamous)Non-vascularizedDermis – underlies the epidermisTough leathery layer composed of fibrous connective tissueGood supply of bloodHypodermis (not considered skin)Made of adipose and areolar tissueStores fat, anchors skin, protects against blows
14 What are the different types of cells in the epidermis? KeratinocytesProduce a fibrous protein called keratinAre formed in the lowest levels of the epidermis.Pushed upward by the production of new cells beneath them.Become dead and scale-likeMillions rub off everyday
15 What are the different types of cells in the epidermis? MelanocytesSynthesizes the pigment melaninMelan-blackCan transfer melanin to keratinocytesProtects skin from ultraviolet light.melanocyteMelanin inkeratinocytes
16 What are the different types of cells in the epidermis? Langerhans’ cellsFormed in bone marrow.Move to the skinMacrophagesLangerhans’cell
17 What are the different types of cells in the epidermis? Merkel CellsHas a spiked appearanceConnected to nerve cells from dermisFunction as sensory receptors for touch.
18 What are the layers of the epidermis? Stratum basale: deepest layer of the epidermis, undergoes rapid cell division.Stratum spinosum: intermediate layer, contain spiny shaped keratinocytes.Stratum corneum: outermost layer cells thick of dead keratinized cells.DandruffAverage person shed 40 pounds of these cells in their lifetime.Everything you see on a human is dead!
20 What are the characteristics of the dermis? Made up of connective tissueRichly supplied with blood vessels and lymph vesselsHas hair follicles, oil and sweat glands and sensory receptorsRidges formed from the papillary layer can form finger prints.
22 Reticular layer of the dermis Filled with dense irregular fibrous connective tissueMatrix is filled with thick bundles of collagen fibers (give the skin strength)Less dense regions are called lines of cleavage or tension lines; surgeons use these to make incisions because they heal quicker.
23 What causes the color of skin? 3 pigments contribute to skin colorMelanin- protein pigment (natural sunscreen)Can range in color from yellow to reddish-brown to blackEveryone has the same number of melanocytes but make varying amounts and colors (differences in skin color)Increased melanin production can caused by sunlight.Carotene-yellow to orange pigment found in carrots.Most commonly found in the palms or soles. Most intense when large amounts of carotene-rich foods are eaten.Hemoglobin- Red blood gives a pinkish hue to fair skin
24 What are the major appendages of the skin? Sweat glandsSebaceous glandsHairsNails
25 What are the types of glands found in the skin? Sweat glands-sudoriferousMerocrine- common sweat glandsHot sweats vs. Cold sweatsApocrine- produce sweat plus a milky or yellowish substance composed of fat and protein.Found in the arm pits and genitaliaThought to be scent glands.Ceruminous- produce cerumen (ear wax)Mammary glands- produce milkSebaceous glands- oil glands (sebum)Softens and lubricates hair and skinSlows water loss and kills bacteria
27 Why is hair useful? Senses insects that land on the skin. Hair on the head protects the head from a blow, sunlight and heat loss.Eyelashes shield the eyeNose hairs filter the air
28 What are hairs? Made from hair follicles Made of dead keratinized skin cellsTwo parts shaft and rootShaft has 3 layers of cellsMedulla(central core)Cortex (bulky layer)Cuticle (heavily keratinized; protects hair)
31 What are the parts of nails? A nail is a scalelike modification of the epidermisMade of tightly compressed keratinized cellsUseful tools to pick up small objects or scratch an itch.Nail matrix is the region responsible for nail growth.
38 Skin Cancer Benign tumors such as warts and moles are not serious. Malignant tumors can start on the skin and invade other body areas.Crucial risk factor- overexposure to UV radiation
39 Types of Skin CancerBasal cell carcinoma- most common, 30% of all white skin people get it.Arises from the stratum basale layer of the skin99% curable if caught earlyDome shaped nodules that form an ulcer in the center.Squamous Cell carcinoma-Arise from stratum spinosumGrows rapidly and metastasizes if not removedSmall red rounded elevation on the skin
40 Skin Cancer Types cont. Melanoma Cancer of melanocytes (very dangerous)5% of skin cancers but rising fastCan arise from preexisting molesAppears as a spreading brown or black patchChance of survival is poor if the lesion is greater than 4 mm thick
45 What is the ABCD rule? Used for recognizing melanoma A-Asymmetry: two sides of the pigmented mole do not matchB-Border irregularity: borders are not smoothC- Color: lesion has a multiple of colorsD- Diameter the spot is larger than 6 mm in diameter (size of a pencil eraser)
48 What are the 3 types of burns? First-degree burns: only the epidermis is damaged. Redness, swelling and pain are common. (sunburn) 2-3 days to healSecond-degree burns: epidermis and upper layers of dermis. Blistering can occur. 3-4 weeks to heal.Third-degree burns: involves the entire thickness of the skin.