Transcript Chapter 5
Chapter 5 Integumentary System 5-1 Integumentary System • Consists of: – – – – Skin Hair Nails Glands • Functions – – – – – Protection Sensation Temperature regulation Vitamin D production Excretion 5-2 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 5-3 Skin • Dermis – Structural strength – Cleavage lines – Two layers • Reticular • Papillary • Epidermis – Avascular – Cells – Layers or strata 5-4 5-5 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 5-6 Dermis and Epidermis 5-7 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 5-8 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 5-9 Epidermal Layers and Keratinization 5-10 5-11 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 5-12 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 5-13 5-14 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 5-15 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 5-16 5-17 5-18 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” 5-19 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 5-20 5-21 5-22 Nails • Anatomy – Nail root proximally – Nail body distally: Eponychium or cuticle • Growth – Grow continuously unlike hair 5-23 5-24 5-25 Burns • Classifications – First-degree – Second-degree – Third-degree • Skin Grafts – Split skin – Artificial skin – Cadavers or pigs 5-26 The Rule of Nines 5-27 Aging Effects • Skin more easily damaged • Skin becomes drier • Functioning melanocytes decrease or increase as with age spots • Sunlight ages skin more rapidly 5-28 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 5-29 5-30 5-31 5-32 5-33 5-34