anatomy and physiology chap 5
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anaTRANSCRIPT
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Anatomy and Physiology, Sixth Edition
Rod R. SeeleyIdaho State UniversityTrent D. StephensIdaho State UniversityPhilip TatePhoenix College
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
*See PowerPoint Image Slides for all figures and tables pre-inserted into PowerPoint without notes.
Chapter 05
Lecture Outline*
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Chapter 5
Integumentary System
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Integumentary System• Consists of:
– Skin– Hair– Nails– Glands
• Functions– Protection– Sensation– Temperature regulation– Vitamin D production– Excretion
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Hypodermis• Skin rests on this,
but not a part• Consists of loose
connective tissue• Types of cells
– Fibroblasts– Adipose cells– Macrophages
• Also called– Subcutaneous tissue– Superficial fascia
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Skin
• Dermis– Structural strength– Cleavage lines– Two layers
• Reticular• Papillary
• Epidermis– Avascular– Cells– Layers or strata
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Cleavage or Tension Lines
• Elastin and collagen fibers oriented in some directions more than others
• Important in surgery– If incision parallel
to lines there is less gapping, faster healing, less scar tissue
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Dermis and Epidermis
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Epidermal Cells• Cell types
– Keratinocytes: Produce keratin for strength– Melanocytes: Contribute to skin color– Langerhans’ cells: Part of the immune system– Merkel’s cells: Detect light touch and pressure
• Desquamate: Older cells slough off• Keratinization: Cells die and produce outer
layer that resists abrasion and forms permeability layer
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Epidermal Strata• Stratum Basale
– Deepest portion of epidermis and single layer– High mitotic activity and cells become keratinized
• Stratum Spinosum– Limited cell division
• Stratum Granulosum– In superficial layers nucleus and other organelles
degenerate and cell dies• Stratum Lucidum
– Thin, clear zone• Stratum Corneum
– Most superficial and consists of cornified cells
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Epidermal Layers and Keratinization
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Thick and Thin Skin
• Thick skin– Has all 5 epithelial strata– Found in areas subject to pressure or friction
• Palms of hands, fingertips, soles of feet
• Thin skin– More flexible than thick skin– Covers rest of body
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Skin Color
• Determined by 3 factors– Pigments
• Melanin: Provides for protection against UV light• Albinism: Deficiency or absence of pigment• Carotene: Yellow pigment
– Blood circulating through the skin• Imparts reddish hue and increases during blushing,
anger, inflammation• Cyanosis: Blue color caused by decrease in blood
oxygen content– Thickness of stratum corneum
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Accessory Skin Structures• Hair
– Found everywhere on human body except palms, soles, lips, nipples, parts of external genitalia, and distal segments of fingers and toes
• Glands– Sebaceous or oil glands– Sudoriferous or sweat glands– Ceruminous glands– Mammary glands
• Nails
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Hair Structure
• Composed of shaft and root– Shaft protrudes
above skin surface– Root located below
surface and base forms the hair bulb
• Has 3 concentric layers– Medulla: Central
axis– Cortex: Forms bulk
of hair– Cuticle: Forms hair
surface
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Hair Growth, Color, and Muscles
• Hair Growth– Cycles
• Growth and resting
– Permanent hair loss• Pattern balding most common
• Hair Color– Caused by varying amounts and types of melanin
• Muscles– Arrector pili: Muscle contraction causes hair to “stand
on end”
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Oil and Sweat Glands• Sebaceous glands
– Produce sebum– Oils hair and skin
surface
• Sudoriferous glands– Merocrine or eccrine
• Most common• Numerous in palms and
soles
– Apocrine• Found in axillae,
genitalia, around anus
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Nails
• Anatomy– Nail root
proximally– Nail body distally:
Eponychium or cuticle
• Growth– Grow continuously
unlike hair
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Burns• Classifications
– First-degree– Second-degree– Third-degree
• Skin Grafts– Split skin– Artificial skin– Cadavers or pigs
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The Rule of Nines
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Aging Effects
• Skin more easily damaged• Skin becomes drier• Functioning melanocytes decrease or
increase as with age spots• Sunlight ages skin more rapidly
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Clinical Disorders• Bacterial infections
– Acne
• Viral Infections– Chicken pox, German measles, cold sores
• Decubitus ulcers or bedsores– Ischemia and necrosis
• Cancer– Basal cell carcinoma– Squamous cell carcinoma– Malignant melanoma