The protective function of the skin of a newborn or infant is an immature function, it occurs because of thin epidermis and dermis, immature basal membrane, a little amount of fibrous structures and a good developing of blood vessels network. The bactericidal function is an immature function, it is due to PH of the newborn skin (6.1-6.7) in an Adult is acidic (4.2-5.6). This pH medium is favorable for developing microbes.
The thermoregulation is immature function as the result of high emission of heat process and immature heat production. The high emission heat processes occur because of a thin skin, a later beginning of sweat glands functioning, a well developed superficial vessel network, and the vessels are in physiological vasodilatation. Muscles of the hair bulbs are poorly developed, so gooseflesh does not appear.
The respiratory function is well developed. It helps immature lungs to perform the respiratory function. The intensity of the respiratory function is more intensive by 8 times in a newborn than in an adult. Well developed respiratory functions are caused by puffy and thin skin, a well developed superficial vessel network, physiological vasodilatation of vessels. The deposition function is well developed. The skin is the depot of blood and water.
The receptor function is well developed. There are a lot of nerves in the skin, so the skin is a peripheral analyzer that grasps endo- and exogenous stimuli. The skin excretes some products of metabolism of fat and carbohydrates and different medicaments. The excretion function of the skin begins with the beginning of functioning sweat and sebaceous glands (3-4 months).
The resorption is well developed. It is caused by puffy and thin skin, well developed superficial vessel network, a great number of sebaceous glands and hair follicles. But resoption depends on the chemical structure of the substance; lipo-soluble substances are well absorbed, water-soluble substances are non-absorbtive.
The buffer function is poorly developed, because in newborns and young children pH of the skin is nearly neutral (pH 6.1-6.7) therefore the skin can’t neutralize acids and alkaline.
The skin synthesizes vitamin D and other biologically active substances. The skin secretes keratin, squalen, calcium and phosphorus. In a newborn, the secretion of keratin and squalen is decreased; the secretion of calcium and phosphorus is increased. The metabolic function is well developed, therefore newborns and young children have a high regeneration of the epidermis and dermis.
As simple as the skin of a newborn or infant may seem, it is complicated and very active functionally.