20 May 2019 Author : José Campos Lopes The skin has multiple functions and accounts for 16-18% of body weight. It is large and an average adult has a surface area of about two m2. It is composed by the juxtaposition and integration of a stratified epithelium with dense connective and adipose tissue. These elements have different origins in embryonic life. The epidermis The epidermis, whose average thickness is no greater than 0.1 mm (except in the palms of the hands and soles of the feet), has: Different layers and cells (keratinocytes, melanocytes, Langerhans cells, Merkel cells); Cutaneous adnexa (e.g. the sebaceous, sweat, eccrine and apocrine glands); Hairs; Nails. The dermis The dermis is formed by: Resident cells (fibroblasts, mast cells, histiocytes and macrophages); Migrant cells, such as lymphocytes, plasma cells and eosinophils. There are also fibres and ground substance in the dermis (collagen and elastin). They include: Epidermal adnexa; Blood and lymph vessels; Nerves, coming from the hypodermis. Resistance of the skin Skin integrity is critical to its function as a barrier allowing human beings to survive in the surrounding hostile environment. Healthy skin has a remarkable resistance to tearing (average adult 1.6 kg / mm2) and elasticity . It maintains body temperature, with special emphasis on perspiration. Along with being a defence barrier, the skin can collect immune and sensory information from the outside. Sensory pain, touch, pressure, thermal and vibratory information includes the important function of interpersonal communication. Meet the dermatology team from Hospital da Luz network. The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
