1、本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。General Anatomy A large organ composed of all 4 tissue types 22 square feet 1-2 mm thick Weight 10 lbs.1本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Overview 3 Major layers of skin Epidermis is epithelial tissue only Dermis is layer of connective ti
2、ssue,nerve&muscle Hypodermis(subcutaneous)is layer of adipose&areolar tissues2本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Overview of Epidermis Stratified squamous epithelium Contains no blood vessels 4 types of cells 5 distinct strata(layers)of cells3本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本
3、人删除。Cell types of the Epidermis Keratinocytes-90%produce keratin Melanocytes-8%produces melanin pigment melanin transferred to other cells with long cell processes Langerhan cells from bone marrow provide immunity Merkel cells in deepest layer form touch receptor with sensory neuron4本文档所提供的信息仅供参考之用，
4、不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Layers(Strata)of the Epidermis Stratum corneum Stratum lucidum Stratum granulosum Stratum spinosum Stratum basale5本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Stratum Basale Deepest single layer of cells Combination of merkel cells,melanocytes,keratinocytes&stem ce
5、lls that divide repeatedly Cells attached to each other&to basement membrane by desmosomes&hemidesmosomes6本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Stratum Spinosum 8 to 10 cell layers held together by desmosomes During slide preparation,cells shrink and look spiny Melanin taken in by phagocyt
6、osis from nearby melanocytes7本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Stratum Granulosum 3-5 layers of flat dying cells Show nuclear degeneration Contain dark-staining keratohyalin granules Contain lamellar granules that release lipid that repels water8本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系
7、网站或本人删除。Stratum Lucidum Seen in thick skin on palms&soles of feet Three to five layers of clear,flat,dead cells Contains precursor of keratin9本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Stratum Corneum 25 to 30 layers of flat dead cells filled with keratin and surrounded by lipids Continuously s
8、hed Barrier to light,heat,water,chemicals&bacteria Friction stimulates callus formation10本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Keratinization&Epidermal Growth Stem cells divide to produce keratinocytes As keratinocytes are pushed up towards the surface,they fill with keratin 4 week journey
9、 unless outer layers removed in abrasion Hormone EGF(epidermal growth factor)can speed up process Psoriasis=chronic skin disorder cells shed in 7 to 10 days as flaky silvery scales abnormal keratin produced11本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Skin Grafts New skin can not regenerate if s
10、tratum basale and its stem cells are destroyed Skin graft is covering of wound with piece of healthy skin autograft from self isograft from twin autologous skin transplantation of patients skin grown in culture12本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Dermis Connective tissue layer composed
11、of collagen&elastic fibers,fibroblasts,macrophages&fat cells Contains hair follicles,glands,nerves&blood vessels Major regions of dermis papillary region reticular region13本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Papillary Region Top 20%of dermis Composed of loose CT&elastic fibers Finger lik
12、e projections called dermal papillae Functions anchors epidermis to dermis contains capillaries that feed epidermis contains Meissners corpuscles(touch)&free nerve endings(pain and temperature)14本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Reticular Region Dense irregular connective tissue Contai
13、ns interlacing collagen and elastic fibers Packed with oil glands,sweat gland ducts,fat&hair follicles Provides strength,extensibility&elasticity to skin stretch marks are dermal tears from extreme stretching Epidermal ridges form in fetus as epidermis conforms to dermal papillae fingerprints are le
14、ft by sweat glands open on ridges increase grip of hand15本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Skin Color Pigments(1)Melanin produced in epidermis by melanocytes same number of melanocytes in everyone,but differing amounts of pigment produced results vary from yellow to tan to black color
15、melanocytes convert tyrosine to melanin UV in sunlight increases melanin production Clinical observations freckles or liver spots=melanocytes in a patch albinism=inherited lack of tyrosinase;no pigment vitiligo=autoimmune loss of melanocytes in areas of the skin produces white patches16本文档所提供的信息仅供参考
16、之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Skin Color Pigments(2)Carotene in dermis yellow-orange pigment(precursor of vitamin A)found in stratum corneum&dermis Hemoglobin red,oxygen-carrying pigment in blood cells if other pigments are not present,epidermis is translucent so pinkness will be evident17本文档所提
17、供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Accessory Structures of Skin Epidermal derivatives Cells sink inward during development to form:hair oil glands sweat glands nails18本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Structure of Hair Shaft-visible medulla,cortex&cuticle Root-below the surface
18、 Follicle surrounds root19本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Hair Related Structures Arrector pili smooth muscle in dermis contracts with cold or fear.forms goosebumps as hair is pulled vertically Hair root plexus detect hair movement20本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Hai
19、r Color Result of melanin produced in melanocytes in hair bulb Dark hair contains true melanin Blond and red hair contain melanin with iron and sulfur added Graying hair is result of decline in melanin production White hair has air bubbles in the medullary shaft21本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处
20、，请联系网站或本人删除。Functions of Hair Prevents heat loss Decreases sunburn Eyelashes help protect eyes Touch receptors(hair root plexus)senses light touch22本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Glands of the Skin Specialized exocrine glands found in dermis Sebaceous(oil)glands Sudiferous(sweat)gla
21、nds Ceruminous(wax)glands Mammary(milk)glands23本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Sebaceous(oil)glands Secretory portion in the dermis Most open onto hair shafts Sebum combination of cholesterol,proteins,fats&salts keeps hair and skin from soft&pliable inhibits growth of bacteria&fungi(
22、ringworm)Acne bacterial inflammation of glands secretions stimulated by hormones at puberty24本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Sudoriferous(sweat)glands Eccrine(sweat)glands most areas of skin secretory portion in dermis with duct to surface regulate body temperature with perspiration
23、Apocrine(sweat)glands armpit and pubic region secretory portion in dermis with duct that opens onto hair follicle secretions more viscous function after puberty,“cold sweat”25本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Ceruminous glands Modified sweat glands produce waxy secretion in ear canal C
24、erumin contains secretions of oil and wax glands Helps form barrier for entrance of foreign bodies Impacted cerumen may reduce hearing26本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Structure of Nails Tightly packed keratinized cells Nail body visible portion pink due to underlying capillaries fre
25、e edge appears white Nail root buried under skin layers lunula is white due to thickened stratum basale Eponychium(cuticle)stratum corneum layer27本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Nail Growth Nail matrix below nail root produces growth Cells transformed into tightly packed keratinized
26、cells 1 mm per week28本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Types of Skin Thin skin covers most of body thin epidermis(.1 to.15 mm.)that lacks stratum lucidum lacks epidermal ridges,has fewer sweat glands and sensory receptors Thick skin only on palms and soles thick epidermis(.6 to 4.5 mm.
27、)with distinct stratum lucidum&thick stratum corneum lacks hair follicles and sebaceous glands29本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。General Functions of the Skin Regulation of body temperature Protection as physical barrier Sensory receptors Excretion and absorption Synthesis of vitamin3
28、0本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Skin Cancer 1 million cases diagnosed per year 3 common forms of skin cancer basal cell carcinoma (rarely metastasize)squamous cell carcinoma (may metastasize)malignant melanomas (metastasize rapidly)most common cancer in young women arise from melano
29、cytes-life threatening key to treatment is early detection watch for changes in symmetry,border,color and size risks factors include-skin color,sun exposure,family history,age and immunological status31本文档所提供的信息仅供参考之用，不能作为科学依据，请勿模仿；如有不当之处，请联系网站或本人删除。Types of Burns First-degree only epidermis(sunburn
30、)Second-degree burn destroys entire epidermis&part of dermis fluid-filled blisters separate epidermis&dermis epidermal derivatives are not damaged heals without grafting in 3 to 4 weeks&may scar Third-degree or full-thickness destroy epidermis,dermis&epidermal derivatives damaged area is numb due to loss of sensory nerves32
