36–3 The Integumentary System Photo Credit: © Getty Images Copyright Pearson Prentice Hall

The Integumentary System The skin, hair, nails, and a variety of glands make up the integumentary system. The skin is the largest organ in the body. Copyright Pearson Prentice Hall

The Integumentary System What are the functions of the integumentary system? Copyright Pearson Prentice Hall

The Integumentary System serves as a barrier against infection and injury. helps regulate body temperature. removes waste products from the body. provides protection against UV radiation from the sun. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Skin The Skin The skin is made up of two main layers—the epidermis and the dermis. Beneath the dermis is a layer of fat (hypodermis) and loose connective tissue that insulates the body. Copyright Pearson Prentice Hall Fat

Copyright Pearson Prentice Hall The Skin Structures of the Skin Nerves Blood vessels Hair Sweat pore Sebaceous gland Hair follicle Epidermis The skin has an outer layer called the epidermis and an inner layer called the dermis. Dermis Muscle Sweat gland Hypodermis Fat Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Skin Epidermis  The outer layer of the skin is the epidermis. The epidermis has two layers. The outer layer is made up of dead cells. The inner layer is made up of living cells. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Skin Cells in the inner layer undergo rapid cell division, producing new cells that push older cells to the surface of the skin. Older cells also begin making keratin. When these cells die, they form a waterproof covering on the skin’s surface. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Skin The epidermis also contains melanocytes produce melanin, a dark brown pigment. Melanin protects the skin from sun damage. Differences in skin color result from different amounts of melanin and where melanocytes are distributed. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Skin The epidermis also contains melanocytes produce melanin, a dark brown pigment. Melanin protects the skin from sun damage. Differences in skin color result from different amounts of melanin and where melanocytes are distributed. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Skin Dermis  The inner layer of the skin is the dermis. The dermis contains collagen fibers, blood vessels, nerve endings, glands, sensory receptors, smooth muscles, and hair follicles. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Skin The dermis contains two major types of glands: sweat glands sebaceous, or oil, glands Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Skin If your body gets too hot, sweat glands produce sweat. When sweat evaporates, it cools the body. Sweat also gets rid of wastes from the blood, along with water. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Skin Sebaceous glands produce an oily secretion called sebum. Sebum spreads out along the surface of the skin and helps to keep the skin flexible and waterproof. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Skin Sebaceous glands produce an oily secretion called sebum. Sebum spreads out along the surface of the skin and helps to keep the skin flexible and waterproof. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Skin Sebaceous glands produce an oily secretion called sebum. Sebum spreads out along the surface of the skin and helps to keep the skin flexible and waterproof. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Hair and Nails Hair  Hair covers most body surfaces. protects the head from uv light from the sun. provides insulation from the cold. prevents dirt and other particles from entering the body. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Hair and Nails Hair is produced by hair follicles, which are tubelike pockets of epidermal cells that extend into the dermis. An individual hair is a column of cells that have filled with keratin and died. The oily secretions of sebaceous glands help maintain the condition of each individual hair. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Hair and Nails Nails  Grow from rapidly dividing cells in the nail root. The nail root is located near the tips of the fingers and toes. During cell division, cells fill with keratin and produce a plate like nail that covers and protects the fingertips and toes. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 36–3 Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 36–3 Keratin provides insulation. a waterproof covering. pigmentation. protection from UV radiation. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 36–3 The dermis contains two types of glands: sweat glands and sebaceous glands. pigment glands. hair follicles. dermal glands. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 36–3 All of the following are found in the dermis EXCEPT nerve endings. blood vessels. sebaceous glands. melanocytes. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 36–3 The function of melanin is to help control the rate of heat loss by the skin. produce sweat. produce a waterproof covering on the surface of the skin. absorb harmful UV radiation. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 36–3 The basic structure of human hair and nails is melanin. sebum. keratin. dermal cells. Copyright Pearson Prentice Hall

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