Chapter 5The Integumentary SystemObjectivesAfter completing this chapter, you should be able to1.describe the anatomy and major functions of the skin.2.explain the basis of different skin colours.3.compare the anatomy, distribution and physiology of the epidermal derivatives listed below:A.hairB.sebaceous glands or oil glandsC.sudoriferous glands or sweat glandsD.ceruminous glandsE.nails.
4.describe how the skin contributes to the regulation of body temperature, the storage of blood, protection, sensation, excretion and absorption, and synthesis of vitamin D.5.outline the steps involved in epidermal wound healing and deep wound healing.Keywords and TopicsMake certain that you can define, and use in context, each of the terms listed below, and that you understand the significance of each of the concepts.1.Describe the anatomy and major functions of the skin. 1. Regulates body temperature. 2. Stores blood. 3. Protects body from external4. Detects cutaneous sensations. 5. Excretes and absorbs substances. 6. Synthesizes vitamin D.environmentA.integumentary system: composed of skin, hair, oil and sweat glands, nails, and sensory receptors. Helps maintain body temperature, protects the body, and provides sensory information about the environment. B.skin or cutaneous membrane: largest organ, covers the external surface of the body. Ranges in thickness, composed of two parts:C.Epidermis: superficial, thin portion composed of epithelial tissue, avascular, no bleedingD.Dermis: Deeper, thicker connective tissue, vascular, bleedsE.subcutaneous (SQ) layer or hypodermis: below the dermis, consists of areolar and adipose tissues. Fibers that extend from the dermis anchor the skin to this layer, which anchors itself to the fascia (connective tissue around muscle and bones. Serves as a storage depot for fat, contains large blood vessels that supply the skin.F.lamellated corpuscle or pacinian corpuscle: sensitive to pressure, located within the SQ layerG.Epidermis: composed ofI.Keratinocyte: make up 90%, arranged in 4 or 5 layers and produce keratin, and lamellar granules which release a water-repellent/sealanta. Keratin: a tough, fibrous protein that helps protect the skin and underlying tissues from the external environment. (abrasions, chemicals, heat, microbes, etc.)II.Melanocyte: 8%, produce melanin, long slender projections extend between keratinocytes and transfer melanin.a.Melanin: yellow-brown or brown-black pigment that contributes to skin color, and absorbs UV light, forms a shield over keratinocyte nuclei on the skin side surface. III.intraepidermal macrophages or Langerhans cell: arise from red bone marrow and migrate to the epidermis, main purpose is immunity, help other