Nursing Entrance Exam

Nursing Preparation Study Guide

6.3 The Integumentary System – Tour of the System No other organ system is as large as the integumentary system integument, this system accounts for about 15% of the total body weight in humans. 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 skin is a key indicator of an individual’s health status, as it provides readily visible information without any intrusive procedures. For example, a patient with yellowing skin is often suffering from jaundice whereas a patient with a blue-gray tint of their skin is likely to be suffering from cyanosis. A deep red hue could show hypertension (high blood pressure); white skin can be an indicator of medical shock. How skin feels can also show disease or trauma. Skin may feel cold, clammy, hot, or dry. 6.3.1 Functions The skin protects internal tissues and organs, and prevents organisms, such as bacteria and viruses, from entering the body. The skin protects the body from dehydrating by acting as a waterproof barrier. It allows a wet body to exist in dry air, allows immersion in fresh water without swelling with water, or immersion in saltwater without becoming desiccated. The skin further protects the body from sudden temperature changes by maintaining homeostasis. On hot days, the skin helps regulate body temperature in three main ways: 1. Arterioles vasodilate and send more blood to superficial capillaries in the skin, which allows heat loss. The hairs on the skin remain flat, preventing the insulating air from becoming trapped between the hairs and the skin. 2. The skin protects the body from UV damage by secreting melanin. Pigmented or freckled skin is an adaptation to intense sunlight. 3. The skin excretes waste materials, such as salts and urea, through sweating, or perspiration, which is essential for cooling the body. The skin stores a variety of substances, including water, fat, glucose, and vitamin D. Human skin produces vitamin D from UV exposure, and it forms new skin cells to repair skin damage. The skin maintains the form and shape of the body. An absence of vitamin D can cause rickets, a condition in children that leads to soft and weak bones. . Often referred to simply as the

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