![]() Arrector pili muscles - these are attached to hair follicles.Lymphatics - an extensive network of thin-walled vessels that nourish and drain the skin.Blood vessels - arteries, arterioles, capillaries, venules and veins carrying blood to and from the skin.Nerves - sensory and autonomic fibres with distinct nerve endings for touch, heat, cold, pressure and pain.Fibroblasts - cells found in the dermis that produce collagen, elastin, ground substance and fibronectin (a glycoprotein).It contains hyaluronic acid, dermatan sulphate, and chondroitin-6-sulphate (these are anionic polysaccharides or glycosaminoglycans). Ground substance - the gel component of the dermis.They return deformed skin to its resting position. Elastin - the protein that makes up thin elastic fibres.It is composed of a triple helix of strong fibres. Collagen - a structural protein making up the bulk of the dermis.The papillary dermis is the upper portion beneath the epidermis, and the lower portion is the reticular dermis. The dermis is made up of connective tissue that supports the epidermis, providing nutrients and protecting it. Pilosebaceous structures containing hair and sebaceous glands.Apocrine glands, scent glands found in armpits and groins.Desmosomes - the structures that stick adjacent keratinocytes tightly together, rather like cement between bricks. ![]() The top layer of cells loosens and falls off. Horny layer - stacks of dead cells without nuclei make up the dry or keratinised stratum corneum.Granular layer - flattened cells filled with dark granules containing keratohyaline protein.The structure of the skin is described as a stratified squamous epithelium, referring to the way the cells are built up in layers. Squamous cells - flat epithelial cells found on the skin surface.Scattered melanocytes are normally found in this layer. Basal layer - the columnar or rectangular cells at the bottom of the epidermis from which new cells are continuously produced.The epidermis also contains pigment cells called melanocytes, which produce melanin, Langerhans cells, which present antigens to the immune system, and Merkel cells, which have a sensory function. The epidermis is a complex ‘brick wall’ made of cells called keratinocytes, which produce a protein called keratin. There is a basement membrane that separates the epidermis from the dermis and acts as a communication channel between the two layers. The skin is considered to have three parts: the outer epidermis, middle dermis and deep subcutaneous tissue. Dermoscopy for pigmented lesions to diagnose melanoma.Wood's lamp (long wave UVA) examination for pigmentary changes and fluorescent infections.Which layer(s) of the skin are involved? If scaly, does the surface flake off easily? If crusted, what is underneath? ![]() The dermatologist will carefully feel individual lesions, noting surface and deep characteristics. When examining the skin, a dermatologist assesses distribution, morphology and arrangement of skin lesions: their number, size, and colour, which sites are involved, their symmetry, shape, and arrangement.
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