Anatomy and Physiology, Sixth Edition Rod R. Seeley Idaho State University Trent D. Stephens Idaho State University Philip Tate Phoenix College Chapter 05 Lecture Outline* *See PowerPoint Image Slides for all figures and tables pre-inserted into PowerPoint without notes. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Chapter 5 Integumentary System

Integumentary System Consists of: Functions Skin Hair Nails Glands Protection Sensation Temperature regulation Vitamin D production Excretion

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

Skin Dermis Epidermis Structural strength Cleavage lines Two layers Reticular Papillary Epidermis Avascular Cells Layers or strata

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

Dermis and Epidermis

Epidermal Cells Cell types Desquamate: Older cells slough off 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

Epidermal Strata Stratum Basale Stratum Spinosum Stratum Granulosum 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

Epidermal Layers and Keratinization

Thick and Thin Skin Thick skin Thin 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

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

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

Hair Structure Composed of shaft and root Has 3 concentric layers 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

Hair Growth, Color, and Muscles 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”

Oil and Sweat Glands Sebaceous glands Sudoriferous 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

Nails Anatomy Growth Nail root proximally Nail body distally: Eponychium or cuticle Growth Grow continuously unlike hair

Burns Classifications Skin Grafts First-degree Second-degree Third-degree Skin Grafts Split skin Artificial skin Cadavers or pigs

The Rule of Nines

Aging Effects Skin more easily damaged Skin becomes drier Functioning melanocytes decrease or increase as with age spots Sunlight ages skin more rapidly

Clinical Disorders Bacterial infections Viral 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