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5 C h a p t e r The Integumentary System
PowerPoint® Lecture Slides prepared by Jason LaPres Lone Star College - North Harris Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
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The integumentary system consists of
Cutaneous membrane Epidermis Dermis Accessory structures Subcutaneous layer
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Integumentary system functions:
Protection Excretion Temperature maintenance Nutrient storage Vitamin D3 synthesis Sensory detection
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Figure 5.1 The Components of the Integumentary System
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Figure 5.2 Thin Skin and Thick Skin
The epidermis is composed of layers of keratinocytes Thin skin = four layers (strata) Thick skin = five layers Figure 5.2
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The epidermis Provides mechanical protection Prevents fluid loss
Keeps microorganisms from invading the body
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Layers of the epidermis:
Stratum germinativum Stratum spinosum Stratum granulosum Stratum lucidum Stratum corneum
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Figure 5.3 The Epidermal Ridges of Thick Skin
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Epidermal characteristics:
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
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Figure 5.4 The Structure of the Epidermis
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Skin color depends on Blood supply Carotene and melanin
Melanocytes produce melanin and protect from UV radiation Epidermal pigmentation Interrupted blood supply leads to cyanosis
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Figure 5.5 Melanocytes Figure 5.5a, b
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Epidermal cells Synthesize vitamin D3 (cholecalciferol) when exposed to UV Respond to epidermal growth factor Growth Division Repair Secretion
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Dermal Organization Papillary layer
Contains blood vessels, lymphatics, sensory nerves of epidermis Reticular layer Contains network of collagen and elastic fibers to resist tension
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Figure 5.7 Dermal Circulation
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Stretch marks Caused by excessive stretching of the dermis
Patterns of collagen and elastic fibers form lines of cleavage
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Figure 5.6 Lines of Cleavage of the Skin
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Dermal Circulation and innervation
Cutaneous plexus arteries found in subcutaneous layer/papillary dermis Cutaneous sensory receptors (light touch, pressure)
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Hypodermis Stabilizes skins position against underlying organs and tissues
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Hairs Originate in hair follicle Composed of root and shaft
Root base (hair papilla) surrounded by hair bulb and root hair plexus Hairs have soft medulla and hard cortex Cuticle = superficial dead protective layer
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Figure 5.8 The Anatomy of a Single Hair
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Hair types Vellus hairs (peach fuzz) Terminal hairs (heavy)
Club hair (cessation of growth) Shed and grow according to hair growth cycle Arrector pili muscle attaches to hair
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Figure 5.9 Hair Follicles Figure 5.9
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Glands in the skin Sebaceous Suderiferous Mammary Ceruminous
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Sebaceous glands Discharge waxy sebum onto hair shaft when associated with hairs Sebaceous follicles discharge onto epidermal surface
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Figure 5.10 Sebaceous Glands and Follicles
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Suderiferous glands Apocrine sweat glands Produce odorous secretion
Merocrine (eccrine) sweat gland Sensible perspiration
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Figure Sweat Glands Figure 5.11a, b
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Other glands Mammary glands
Structurally similar to apocrine sweat glands Ceruminous glands In ear, produce waxy cerumen
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Nails Nail body covers the nail bed
Nail production occurs at the nail root Eponychium (cuticle) overlies root Free edge of nail extends over hyponychium
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Figure 5.12 The Structure of a Nail
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Injury and repair Regenerates easily
Regeneration process includes formation of Scab Granulation tissue Scar tissue
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Figure 5.13 Integumentary Repair
Figure 5.13, step 1-2
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Figure 5.13 Integumentary Repair
Figure 5.13, step 3-4
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You should now be familiar with:
The components of the integumentary system, including their physical relationships. The functions of the integumentary system. The main features and functions of the epidermis and dermis. Individual and racial differences in skin. The effects of UV light on the epidermis. The structure and function of the various accessory organs of the skin. How the skin responds to repair.
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