Integumentary System Foundations

Skin is a barrier, a sensory organ, a temperature regulator, and a visible indicator of perfusion and inflammation. The epidermis limits fluid loss and blocks many external threats. The dermis contains blood vessels, nerves, hair follicles, and sweat glands. Subcutaneous tissue cushions deeper structures and provides insulation. These layers depend on an adequate blood supply. When perfusion falls, the skin may become cool, pale, dusky, or painful before tissue breakdown is obvious. Diabetes, peripheral vascular disease, malnutrition, immunosuppression, and advanced age can therefore turn a minor wound into a slow-healing one: oxygen delivery, immune response, collagen production, or all three may be impaired. For bedside assessment, the skin is not merely a surface to inspect. Compare both sides of the body and connect what you see with mobility, sensation, continence, nutrition, circulation, medications, and recent procedures. A new painful colour change over the sacrum in an immobile patient has a different priority from a chronic, symmetrical change in both lower legs.