Textbook Notes (368,588)
Canada (161,988)
HLTC22H3 (102)
Anna Walsh (49)
Chapter 5

Chapter 5

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Health Studies
Anna Walsh

Health Illness and Optimal Aging Biological and Psychological Perspectives Carolyn M Aldwin Diane F Gilmer Foreword by James Birren Section II Aging of Biological SystemsChapter 5 Aging of the Skin and Musculosketal System Skin Basic Anatomy and Physiology y The skin or integumentary system has several major functions It is the front line of defense against harmful environmental influences and is an important part of our immunological and endocrine systems The skin is critical in temperature maintenance and in general aids in homeostasis Sensory nerves in the skin allow us to monitor the environment but also warn us of danger through pain Finally the integumentary system has important symbolic functions in that it is a key component of our appearance and is a critical source of cues that affect social integration y The outermost layer of skin is called the epidermis and the second layer is the dermis Beneath the epidermis and dermis is a layer of subcutaneous fat Hair follicles nail beds and nails and sweat and sebaceous glands are embedded in the various layers y The epidermis consist mostly of keratinocytes more than 90 of all epidermal cells cells that protect the skin from outside harm and help it heal if it is injured As young cells keratinocytes are found deep in the epidermis They slowly move to the surface of the epidermis as they age a process that takes about 30 days If the skin is injured the keratinocytes will reproduce and turn over at a more rapid rate allowing the damage to be repaired Keratinocytes are also necessary for the synthesis of vitamin D3 which is eventually used in the absorption of calcium Gilchrest 1999 y Melanocytes which make up about 2 of the cells in the epidermis produce melanin for keratinocytes and give color to the skin Exposure to the sun results in an increase in melanin production by these cells which helps to protect the skin from damage Finally Langerhans cells although they make up only about 1 of the cells in the epidermis are an important part of the immune system Along with the mast cells found in the dermal layer they respond to toxic allergic stimuli y The dermis consists largely of collagen and elastin tissue which provides strength and elasticity to the skin Blood vessels lymphatic tissue and nerves are in this connective tissue as are the sweat glands and hair follicles Cells in the dermis layer include mast cells that are responsible for the skins cutaneous fat which consists mostly of adipocytes fat cells Subcutaneous fat gives shape and form to the body and provides protection and insulation AgeRelated Changes
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