Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Fundamentals of Anatomy & Physiology SIXTH EDITION Chapter 5, part 1 The Tissue Level of Organization--Integument
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Learning Objectives List the components of the integumentary system, including their physical relationships. Specify the functions of the integumentary system. Describe the main features and functions of the epidermis and dermis. Discuss individual and racial differences in skin. Discuss the effects of UV light on the epidermis. Explain the structure and function of the various accessory organs of the skin. Explain how the skin responds to injury and aging.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings SECTION 5-1 The Integumentary System: An Overview
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Cutaneous membrane Epidermis Dermis Accessory structures Subcutaneous layer The integumentary system consists of
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Protection Excretion Temperature maintenance Nutrient storage Vitamin D3 synthesis Sensory detection Integumentary system functions:
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 5.1 The Components of the Integumentary System Figure 5.1
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings SECTION 5-2 The Epidermis
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings The epidermis is composed of layers of keratinocytes Thin skin = four layers (strata) Thick skin = five layers Figure 5.2 Thin Skin and Thick Skin Figure 5.2
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Provides mechanical protection Prevents fluid loss Keeps microorganisms from invading the body The epidermis
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Stratum germinativum Stratum spinosum Stratum granulosum Stratum lucidum Stratum corneum Layers of the epidermis:
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 5.3 Figure 5.3 The Epidermal Ridges of Thick Skin
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Cells accumulate keratin and eventually are shed Epidermal ridges are interlocked with dermal papillae Fingerprints Improve gripping ability Langerhans cells (immunity) in s. spinosum Merkel cells (sensitivity) in s. germinativum Epidermal characteristics:
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 5.4 The Structure of the Epidermis Figure 5.4
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Blood supply Carotene and melanin Melanocytes produce melanin and protect from UV radiation Epidermal pigmentation Interrupted blood supply leads to cyanosis Skin color depends on
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 5.5 Melanocytes Figure 5.5a, b
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Synthesize vitamin D3 (cholecalciferol) when exposed to UV Respond to epidermal growth factor Growth Division Repair Secretion Epidermal cells
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings SECTION 5-3 The Dermis
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Papillary layer Contains blood vessels, lymphatics, sensory nerves of epidermis Reticular layer Contains network of collagen and elastic fibers to resist tension Dermal Organization
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 5.8 Dermal Circulation Figure 5.8
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Caused by excessive stretching of the dermis Patterns of collagen and elastic fibers form lines of cleavage Stretch marks
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 5.7 Lines of Cleavage of the Skin Figure 5.7
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Cutaneous plexus arteries found in subcutaneous layer/ papillary dermis Cutaneous sensory receptors (light touch, pressure) Dermal Circulation and innervation