skin皮肤-英文课件-汕头大学医学院

The skin and Skin Regenerative MedicineKayiName?Aging skinskin the largest organ in the body protect sense regulate temperature Production of Vitamin DClininiansDermatology-dermatologistPlastic and esthetic surgery-plastic surgeonKeratinocytefibroblastOBJECTIVEMaster skin structure and functionepidermis-keratinization:proliferation/differentiationAcquaitance Anomalies of skin- common skin diseases AdvanceSkin regenerative medicineINTRODUCTIONepidermisdermishypodermisDermisPapillary layer+ Reticular layer第二节真皮skin dermis真皮papillary layer 乳头层reticular layer 网织层appendages附属器hair 毛 sebaceous gland 皮脂腺sweat gland 汗腺 THE STRUCTURE OF SKINepidermis表皮stratum corneum 角质层stratum lucidum (透明层 )stratum granulosum 颗粒层stratum spinosum 棘层stratum basale 基底层nail 指 (趾 )甲 EPIDERMIS主要细胞组成keratinocyte(角质形成细胞 ) non-keratinocyte(非 角质形成细胞 ) differentiationstratum corneum角质层stratum granulosum颗粒层stratum lucidum(透明层 )stratificationstratum basale基底层stratum spinosum棘层（一） Epidermal stratification and differentiationPSORIASIS 银屑病red and white hues of scaly patches appearing on the top first layer of the epidermis (skin). Langerhans cell(郞格汉斯细胞 )Langerhans cells are dendritic cells (antigen-presenting immune cells) of the skin and mucosa, and contain large granules called Birbeck granules. They are present in all layers of the epidermis, but are most prominent in the stratum spinosum. In skin infections, the local Langerhans cells take up and process microbial antigens to become fully functional antigen-presenting cells.Langerhans cells derive from the cellular differentiation of monocytes with the marker “Gr-1“ (also known as “Ly-6G/Ly-6C“). This differentiation requires stimulation by colony stimulating factor (CSF)-1.6 They are similar in morphology and function to macrophages.Albinos lack an enzyme called tyrosinase. Tyrosinase is required for melanocytes to produce melanin from the amino acid tyrosine melanocyte(黑素细胞 )Melanocytes are melanin-producing cells located in the bottom layer (the stratum basale) of the skins epidermis, the middle layer of the eye (the uvea), the inner ear, meninges,Melanin is a pigment that is responsible primarily for the color of skin.No difference in melanocyte number between species.The distribution and tyrosinase activity !Melanoma(黑色素瘤 ):4% of all diagnosed skin cancers, melanoma begins in the melanocytes, cells within the epidermis that give skin its color. Melanoma has been coined “the most lethal form of skin cancer” because it can rapidly spread to the lymph system and internal organs. With early detection and proper treatment, the cure rate for melanoma is about 95%. Once its spreads, the prognosis is poor. Melanoma most often develops in a pre-existing mole or looks like a new mole, which is why it is important for people to know what their moles look like and be able to detect changes to existing moles and spot new moles. The Hair Sebaceous Glands Sweat Glands The Nails The Accessary Structures of the Skin Acne vulgaris (or cystic acne) is a common disease, characterized by areas of skin with scaly red skin, blackheads and whiteheads, pinheads, pimples, nodules and possibly scarring. Acne affects mostly skin with the densest population of sebaceous follicles; these areas include the face, the upper part of the chest, and the back. Severe acne is inflammatory, but acne can also manifest in noninflammatory forms.2 The lesions are caused by changes in pilosebaceous units, skin structures consisting of a hair follicle and its associated sebaceous gland, changes that require androgen stimulation. Acne occurs most commonly during adolescence, and often continues into adulthood. In adolescence, acne is usually caused by an increase in testosterone, which people of both genders accrue during puberty.Alopecia Totalis(全頭脱毛症）Alopecia means loss of hair from the head or body. baldness, Hemidesmosomes (HD) are very small stud- or rivet-like structures on the inner basal surface of keratinocytes in the epidermis of skin. They are similar in form to desmosomes when visualized by electron microscopy. While desmosomes link two cells together, hemidesmosomes attach one cell to the extracellular matrix. Desmosomes are molecular complexes of cell adhesion proteins and linking proteins that attach the cell surface adhesion proteins to intracellular keratin cytoskeletal filaments.The cell adhesion proteins of the desmosome, desmoglein and desmocollin, are members of the cadherin family of cell adhesion molecules. They are transmembrane proteins that bridge the space between adjacent epithelial cells by way of homophilic binding of their extracellular domains to other desmosomal cadherins on the adjacent cell. Both have five extracellular domains, and have calcium-binding motifs.Age-associated skin changes include thinning, skin laxity, fragility, and wrinkles. Sun-exposed areas demonstrate additional aging changes, including dyspigmentation, premature wrinkling, telangiectasia, and actinic elastosis.UVA 400 315 nmUVB 315 280 nmThe sun emits ultraviolet radiation in the UVA, UVB, and UVC bands. The Earths ozone layer blocks 9799% of this UV radiation from penetrating through the atmosphere. Of the ultraviolet radiation that reaches the Earths surface, 98.7% is UVA PhotoagingUV and molecular and genetic changesUVB ray is considered as a primary mutagen that can only penetrate through the epidermal or outermost layer of the skin, resulting in DNA mutations. The epidermal layer does not contain any blood vessels or nerve endings but melanocytes and basal cells are embedded in this layer. Upon exposure to UVB rays, melanocytes will produce melanin, a pigment that gives the skin its color tone. However, UVB will cause the formation of freckles and dark spots, both of which are symptoms of photoaging. With constant exposure to UVB rays, signs of photoaging might appear and precancer