The skin is the largest organ of the human body and of transcendental importance. It is our outer covering and its basic function is to separate the organism from the environment. The skin is a large organ, for which an area of approximately 2 m 2 and a weight of 4 kg is approximately calculated , which is approximately 6% of the total body weight. In this post we will explain its main functions and learn a little more about its structure What are the main functions of the skin? Protective: barrier against mechanical, chemical or toxic aggression and against pathogenic microorganisms; filter against ultraviolet radiation. Thermoregulator: protection from heat and cold, and maintenance of body temperature. Hydro-electrolytic balance : maintains the balance of body fluids, acting as a barrier against the possible loss of water. Sensory: transmits touch, pressure, temperature and pain through receptors and nerve endings. Emotional: we externalize our emotional state through the skin cell; we blush, we turn pale, our hair stands on end and we emit odors (pheromones). What is the structure of our skin? From the most superficial to the deepest, it is distributed in three layers of tissue, with a different embryological origin: The epidermis: The epidermis is a polylaminated and keratinized flat epithelium, which covers the entire body surface. It is the layer of skin with the highest number of cells and with an extraordinarily large turnover dynamics. The cells grow from the inside (basal layer) to the outside (horny layers). It has a variable thickness (from 0.1 mm to 1 or 2 mm in the palms of the hands and the soles of the feet). Cell types: Keratinocytes (90%): they produce keratin, which gives cohesion to the tissue and waterproofs the dermis. Melanomas (5-10%): synthesize melanin, which is our natural pigment and protects us from ultraviolet radiation. The color of the skin does not depend on its number, but on its size. Langerhans cells (2-5%): immune defense. Merkel cells: sensory cells.
