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ESSENTIALS Unit 2 Integumentary System (Skin) OF HUMAN ANATOMY & PHYSIOLOGY

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  • ESSENTIALS

    Unit

    2Integumentary System (Skin)

    ESSENTIALS

    OF HUMAN

    ANATOMY

    & PHYSIOLOGY

  • Integumentary System

    �Skin (cutaneous membrane)

    �Skin derivatives

    �Sweat glands

    �Oil glands

    �Hairs�Hairs

    �Nails

  • Skin Functions

    �Protects deeper tissues from:�Mechanical damage

    �Chemical damage

    �Bacterial damage

    �Thermal damage

    �Ultraviolet radiation�Ultraviolet radiation

    �Desiccation

    �Aids in heat regulation

    �Aids in excretion of urea and uric acid

    �Synthesizes vitamin D

  • Skin Structure

    �Epidermis- outer layer

    �Stratified squamousepithelium

    �Keratinized

    �Dermis

    Dense connective�Dense connective

    tissue

  • Layer of Epidermis

    �Stratum basale�Cells undergoing mitosis

    �Next to dermis

    �Stratum spinosum

    �Stratum granulosum

    �Stratum lucidum�Occurs only in thick skin

    �Stratum corneum�Shingle-like dead cells

  • Dermis

    �Two layers�Papillary layer�Projections called dermal papillae

    �Pain receptors

    �Capillary loops

    �Reticular layer�Reticular layer�Blood vessels

    �Glands

    �Nerve receptors

  • Hypodermis

    �Deep to dermis

    �Not part of the skin

    �Anchors skin to underlying organs

    �Mostly adipose tissue

  • Skin Structure

  • Skin Renewal

  • Normal Skin Color Determinants�Melanin�Pigment produced by melanocytes

    �Melanocytes are mostly in the stratum basale

    �Yellow, brown or black pigments

    �Genetics and sunlight exposure

    �Carotene�Carotene�Orange-yellow pigment in some vegetables

    �Hemoglobin�Red coloring (blood cells in capillaries)

    �Oxygen content determines the extent of red coloring

  • Skin Color Variation

  • Appendages of the Skin

    �Sebaceous glands�Produce oil� Lubricate skin

    �Kill bacteria

    �Most ducts empty into hair follicles

    �Activated at puberty�Activated at puberty

  • Appendages of the Skin

    �Sweat glands

    �Widely distributed in skin

    �Eccrine (most numerous)

    � Open via duct to pore on skin surface

    �Apocrine

    � Ducts empty into hair follicles� Ducts empty into hair follicles

  • Sweat and Its Function

    �Composition�Mostly water

    �Some metabolic waste

    �Fatty acids and proteins (apocrine only)

    �Function�Dissipate excess heat�Dissipate excess heat

    �Excrete waste products

    �Acidic nature inhibits bacteria growth

    �Odor is from associated bacteria

  • Heat Regulation

  • Appendages of the Skin

    �Hair�Produced by hair bulb

    �Consists of hard keratinized epithelial cells

    �Melanocytes provide pigment for hair color

  • Hair Anatomy

    �Central medulla

    �Cortex surrounds medulla

    �Cuticle outer layer�Most heavily keratinized

  • Associated Hair Structures

    �Hair follicle�Dermal and epidermal

    sheath surround hair root

    �Arrector pili�Smooth muscle

    �Sebaceous gland�Sebaceous gland

    �Sweat gland

  • Appendages of the Skin

    �Nails

    �Scale-like modifications of the epidermis

    �Heavily keratinized

    �Stratum basale extends beneath nail bed

    �Responsible for growth

    �Colorless- lack of pigment�Colorless- lack of pigment

  • Nail Structures

    �Free edge

    �Body

    �Root of nail

    �Eponychium- proximal nail fold that projects onto the nail bodyprojects onto the nail body