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CLINICAL APPLICATION OF FOUNDATIONAL SCIENCES
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The integumentary system is the largest organ in the body and is important to our survival in many ways.* The skin is a membranous barrier between our internal system and the environment and responds to external and internal changes. The examination requires an understanding of the structures and functions of the system. Understanding the healthy and disease states of skin, hair, nails, mucous membranes, circulation, and sensory structures is essential to the examination.
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The integumentary system has two major components, the cutaneous membrane (skin) and accessory structures (Figure 4–1). The skin is divided into three layers: the epidermis, the dermis, and the subcutaneous tissue. The accessory structures include the hair, nails, vascular supply, sweat glands, and sebaceous glands. The skin is the site of many complex and dynamic processes, which include being a protective barrier, having immunologic functions for first-line defenses, and functions of melanin production, vitamin D synthesis, sensation, temperature regulation, protection from trauma, and aesthetics.1
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