Anatomy & Physiology I and II

Anatomy & Physiology Study Guide

Chapter 6: The Integumentary System No other organ system is as large as the integumentary system. Often referred to simply as the integument, this system accounts for about 16 percent of the total human body weight. The integumentary system is the body’s first line of defense against the external environment. The integumentary system has two major components: the cutaneous membrane, or skin, and the accessory structures. The cutaneous membrane has two components: the epidermis, or superficial epithelium, and the dermis, an underlying area of connective tissues. The accessory structures are located primarily in the dermis. Many protrude through the epidermis, such as hair, nails, and multicellular exocrine glands. The loose connective tissue of the hypodermis, also known as the subcutaneous layer, separates the integument from bones and the deep fascia around other organs of the body. The general functions of the skin and hypodermis include: • Protection of underlying tissues and organs • Excretion of salts, water, and organic wastes • Maintenance of normal body temperature • Production of melanin, which provides protection from ultraviolet radiation • Production of keratin, which protects against abrasion and serves as a water repellent • Synthesis of vitamin D3 • Storage of lipids in adipocytes and adipose tissue • Detection of touch, pressure, pain, and temperature stimuli

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