dorsalcavities例析.ppt

The frontal [fr?nt(?)l] plane [ple?n] may divide [d?va?d] the body into four major cavities[k?v?ti] : two dorsal [d??s(?)l] cavities and two ventral [ventr(?)l] cavities. Exercise: change the following combining forms into adjectives Purposes of the skin Protecting Housing nerve receptors Secreting fluids si?kr?t] Regulating [r?gj?,let] temperature[temp(?)r?t??] Protecting Keeping pathogens [p?θ?d??ns] and harmful chemicals from entering the body. Stopping critical body fluids from escaping[iskeip] the body preventing injury[?n(d)?(?)r?] to the internal organs lying underneath [?nd?ni?θ] the skin. Housing nerve receptor Sensory[sens(?)r?] receptors in the middle layer of the skin Secreting fluids two types of skin glands: sweat and sebaceous[s?be???s] . Sweat glands secret sweat, which can create a cooling effect[?fekt] when sweat evaporates. The sebaceous glands, produce sebum [si?b?m] which can lubricate [lu?br?ke?t] the skin surface. Regulating temperature Release [r?‘li?s]释放heat: sweat evaporation dilate[da?‘le?t] 扩张superficial blood vessels Conserve heat: constrict blood vessels adipose[?d?p??s; -z] / fat The layers[lei?s] of skin Epidermis Dermis Subcutaneous[,s?bkju?te?n??s] layer Epidermis Epidermis: outmost layer. It is composed of squamous [‘skwe?m?s] epithelial[,ep?’θi?l??l cells. It is referred as stratified[‘str?t?,fa?d] 分层 squamous epithelium. No blood supply Function of epidermis Basal[be?s(?)l] layer new cells rise to the surface die filled with keratin toughen the skin Melanocytes in basal layer melanin[mel?n?n] provide color of the skin, protect against damage from the ultraviolet rays of the sun. Layers of the epidermis from the deepest to the outermost basale/ basal layer Spinosum Granulosum Stratum lucidum Stratum corneum Majors cells in the epidermis Melanocytes: produce melanin Dendritic/ Langerhans cells: be involved in epidermal