Sweat glands and skin derivatives
Sweat glands lie in the dermis as long tubes; there are especially many on the palms, soles and forehead. Sweat is about 98–99% water, the rest salts and metabolic products; it carries away excess heat by evaporating and keeps body temperature. Sebaceous glands open into the hair follicle (none on palms and soles); their secretion softens skin and hair and protects against microbes. In adolescence hormones make sebaceous glands more active, so acne on the face and stronger body odour can appear – this is normal; washing skin with mild soap and wearing clean clothes help, do not squeeze pimples, and if severe see a doctor. Hair is a skin derivative: the part above the skin is the shaft, the part inside is the root; it grows from the root bulb, and pigment decides hair colour. A nail is a horny plate protecting the fingertip; it grows from root cells. Care: wash hair regularly, keep nails clean and short (microbes gather under nails), and use sharp tools for hair and nails only with adult help.
Hygiene chart: face, hands, hair, nails, feet – how often per week and what care. Agree with your family. Use sharp tools (scissors, nail clippers) only with an adult’s help.