ANAPHY

• The integumentary system consists of the skin and its accessory structures, including the hair, nails, sebaceous glands, and sweat glands.
• The skin is the exterior covering of the body, weighing more than 6 pounds in the average adult, and covering more than 3,000 square inches.
• The skin is the largest organ of the body, supplied with blood vessels and nerves.
• Skin is the largest sense organ as it covers the whole body, helping to feel the things around us by touching, whether they are hot or cold, smooth or rough, dry or wet, hard or soft.
• Skin covers the body and protects it from germs.
• The skin inhibits excessive loss of water and electrolytes.
• The skin produces a protective pigmentation to protect the body against excessive exposure from the sun.
• The skin helps produce the body’s supply of Vitamin D.
• The skin provides protection against invasion by bacteria and other harmful agents.
• The skin protects delicate cells beneath the surface from injury.
• When the body is too hot, the blood vessels in the skin dilate, bringing more blood to the surface for cooling by radiation, and sweat glands secrete more sweat that cools the body when it evaporates.
• The skin regulates body temperature when the body is too cold, the skin’s blood vessels constrict, allowing more heat-carrying blood to circulate to the muscles and organs.
• The skin provides sensations, containing millions of nerve endings that act as sensory receptors for pain, heat, cold, and pressure.
• The skin has two layers, the epidermis and the dermis.
• The stratum corneum, the outermost strata of the epidermis, is mostly dead cells, filled with a protein substance called keratin, and is thicker on the soles of the feet than on the eyelids.
• The stratum lucidum is a translucent layer lying directly beneath the corneum, it may not even exist in thinner skin, and cells in this layer are also dead or are in the process of dying.
• The stratum granulosum is one or more layers of cells starting to die and become hard, they are in the process of keratinization, becoming fibrous protein similar to that in hair and nails.
• The stratum germinativum is composed of several layers of living cells capable of cell division, it is the innermost layer of the epidermis, and contains melanin, the pigment that gives color to the skin.
• The dermis contains the lymphatics, nerves, nerve endings, blood vessels, sebaceous and sweat glands, elastic fibers, and hair follicles.
• The dermis is beneath the epidermis and is composed of connective tissue.
• The papillary layer of the dermis is arranged into microscopic structures that form ridges, these are the finger- and footprints.
• Sudoriferous glands are sweat glands, with about 2 million distributed over the surface of the body, more numerous on the palms of the hands, soles of the feet, forehead, and axillae, producing sweat which evaporates and creates a cooling effect, rids the body of waste through the pores of the skin, and accumulates, may become odorous by the action of bacteria.
• The transparent cuticle covers the hair shaft like shingles on a roof, protecting it from the elements and chemicals, and from losing moisture.
• When the cuticle is damaged and exposes the cortex, hair looks dull and dry.
• The subcutaneous tissue is composed of adipose and connective tissue, supporting, nourishing, insulating, and cushioning the skin.
• The hair is a threadlike structure formed by a group of cells that develop within a hair follicle or socket, with a shaft that is visible and a root that is embedded in the follicle.
• The hyponychium is under the free edge of the nail and also creates a waterproof barrier, fusing the skin of the finger to the underside of the nail plate.
• The subcutaneous tissue is composed of adipose and connective tissue, supporting, nourishing, insulating, and cushioning the skin.
• Ingrown nails are those that have curled down or around and are growing into the skin, which may become swollen and inflamed.
• The arrector pili muscle is attached to the side of each follicle and is stimulated by skin irritants, emotional arousal, or cold temperatures, causing the hair to stand on end.
• The dermis is connected to underlying tissue by the subcutaneous tissue.
• Sebaceous glands are oil glands with tiny ducts that open into each hair follicle, secreting sebum which lubricates the hair and skin, with the amount of secretion varying with age, puberty, and pregnancy.
• The medulla is a inner hollow core that runs the length of the shaft.
• The reticular layer is a white fibrous tissue that supports the blood vessels beneath the papillary layer.
• The cuticle, also called the eponychium, fuses the nail plate and the skin of the finger together to form a waterproof barrier.
• The average person loses approximately ½ liter of fluid through sweating each day.
• The cortex provides most of the hair’s weight, contains melanin which provides color to the hair, stores oils, provides flexibility and elasticity, and adds shape to the hair.
• The base of each hair follicle is a bulb enclosing a loop of capillaries called the hair papilla, which provides nourishment to the hair and is one of the few living parts of the hair, responsible for hair growth.
• Fingernails and toenails are hard keratin structures that protect the ends of the fingers and toes