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Essentials of Human Anatomy & Physiology Seventh Edition Elaine N. Marieb Chapter 4 Skin and Body Membranes Slides 4.1 – 4.44 Lecture Slides in PowerPoint by Jerry L. Cook Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Skin and Body Membranes Body membranes cover surfaces, line body cavities, and form protective sheets around organs Function of body membranes Line or cover body surfaces Protect body surfaces Lubricate body surfaces Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.2 Classification of Body Membranes Epithelial membranes Cutaneous membrane Mucous membrane Serous membrane Connective tissue membranes Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.3 Cutaneous Membrane Cutaneous membrane = skin A dry membrane Outermost protective boundary Superficial epidermis Keratinized stratified squamous epithelium Underlying dermis Mostly dense (fibrous) connective tissue Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 4.1a Slide 4.4 Mucous Membranes Surface epithelium Type depends on site Underlying loose connective tissue (lamina propria) Lines all body cavities that open to the exterior body surface Often adapted for absorption or secretion Wet membranes bathed in secretions Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 4.1b Slide 4.5 Serous Membranes Surface simple squamous epithelium Underlying areolar connective tissue Lines open body cavities that are closed to the exterior of the body Occur in pairs – parietal and visceral Serous layers separated by serous fluid Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 4.1c Slide 4.6 Serous Membranes Specific serous membranes Peritoneum Abdominal cavity Pleura Around the lungs Figure 4.1d Pericardium Around the heart Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.7 Connective Tissue Membrane Synovial membrane Areolar connective tissue only Lines fibrous capsules surrounding joints Line small sac of connective tissue called bursae and the tube-like tendon sheaths Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 4.2 Slide 4.8 Integumentary System Skin (cutaneous membrane) Skin derivatives Sweat glands Oil glands Hairs Nails Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.9 Skin Functions Protects deeper tissues from: Mechanical damage Chemical damage Bacterial damage Thermal damage Ultraviolet radiation Desiccation Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.10 Skin Functions Protective and cushioning Waterproof Aids in heat regulation Aids in excretion of salts, urea and uric acid Synthesizes vitamin D Contains sensory receptors Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.11 Skin Structure Epidermis – outer layer Stratified squamous epithelium Often keratinized (hardened by keratin) Dermis Dense connective tissue Both firmly connected but can separate such as in a blister Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.12 Skin Structure Deep to dermis is the hypodermis Not part of the skin Anchors skin to underlying organs Composed mostly of adipose tissue Serves as shock absorber and insulation for deeper tissues Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.13 Layer of Epidermis Stratum basale – deepest layer Cells undergoing mitosis Lies next to dermis and receives nutrients from the dermis by diffusion Stratum spinosum – old stratum basale cells Stratum granulosum – old stratum spinosum cells Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.14 Layer of Epidermis Stratum lucidum Occurs only in thick, hairless skin Stratum corneum Shingle-like dead cells that are ¾ of the epidermal thickness Completely filled with keratin cells called cornified or horny cells Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.15 Melanin Pigment (melanin) produced by melanocytes Color is yellow to brown to black Melanocytes are mostly in the stratum basale Amount of melanin produced depends upon genetics and exposure to sunlight Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.16 Dermis – the “hide” Two layers Papillary layer Projections called dermal papillae Pain receptors and touch receptors Capillary loops for nutrients Result in fingerprints Reticular layer Blood vessels Sweat and oil glands Nerve receptors Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.17 Dermis – the “hide” Both collagen and elastic fibers are found in the dermis Collagen – responsible for the toughness of the dermis and for binding water to keep it hydrated Elastic fibers – give skin elasticity when we are young but lessens as we age along with collagen Lots of blood vessels play a role in maintaining body temperature Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.18 Skin Structure Figure 4.4 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.19 Normal Skin Color Determinants Melanin – amount and kind Yellow, brown or black pigments Carotene Orange-yellow pigment from some vegetables Hemoglobin Red coloring from blood cells in dermis capillaries Oxygen content determines the extent of red coloring Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.20 Normal Skin Color Determinants Redness or erythema – blushing Pallor or blanching – pale from fear or anemia, low blood pressure, or impaired blood flow Jaundice or yellow cast – liver disorder where excess bile pigments are absorbed in the blood Bruises or black-and-blue marks – where blood has escaped from vessels and clotted in the tissue spaces – called hematomas Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.21 Appendages of the Skin Arise from the epidermis and play a role in maintaining homeostasis of the body Cutaneous glands – exocrine glands Release their secretions to the skin surface via ducts Sebaceous glands and sweat glands Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.22 Appendages of the Skin Sebaceous glands Produce oil - sebum Lubricant for skin Kills bacteria Prevents hair from becoming brittle Most with ducts that empty into hair follicles Glands are activated at puberty Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.23 Appendages of the Skin Sweat glands – sudoriferous glands Widely distributed in skin Two types Eccrine Open via duct to pore on skin surface Apocrine Ducts empty into hair follicles Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.24 Sweat and Its Function Composition Mostly water with some salts and vitamin C Some metabolic waste and lactic acid Fatty acids and proteins (apocrine only), which may have a milky or yellowish color Function Helps dissipate excess heat – eccrine only Excretes waste products Acidic nature inhibits bacteria growth Odor is from associated bacteria living off proteins and fats Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.25 Appendages of the Skin Hair Serves a few minor protective functions Used to serve as insulation and still does in some animals Produced by a hair follicle – flexible epithelial structure Part of the hair enclosed in the follicle is the root Part projecting from the surface of the scalp is the shaft Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.26 Appendages of the Skin Hair Produced by hair bulb matrix Consists of hard keratinized epithelial cells Melanocytes provide pigment for hair color Figure 4.7c Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.27 Hair Anatomy Central core called the medulla Cortex surrounds medulla Cuticle on outside of cortex formed from a single layer of cells that overlap like shingles on a roof to keep hairs separated Most heavily keratinized to provide strength Worn more at tips to cause split ends Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 4.7b Slide 4.28 Associated Hair Structures Hair follicle Dermal (provides blood vessels) and epidermal sheath surround hair root Arrector pilli Smooth muscle cause the hair to stand up – goose bumps Sebaceous (oil) gland Sweat gland Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 4.7a Slide 4.29 Nail Structures Each nail has three parts Free edge Body Root of nail Eponychium – proximal nail fold that projects onto the nail body – often called cuticle Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 4.9 Slide 4.30 Appendages of the Skin Nails Scale-like modifications of the epidermis Heavily keratinized Stratum basale extends beneath the nail bed The thickened proximal area called the nail matrix is responsible for nail growth Lack of pigment makes them colorless Appear pink due to blood vessels underneath White crescent – lunula – thickened nail matrix Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.31 Skin Homeostatic Imbalances Infections Athletes foot – tinea pedis Caused by fungal infection on feet Boils and carbuncles Caused by bacterial infection – Staphylococcus aureus – in hair follicles and sebaceous glands Cold sores – fever blisters Caused by herpes simplex viral infection usually on lips and in oral mucosa of the mouth Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.32 Skin Homeostatic Imbalances Infections and allergies Contact dermatitis Exposures to certain chemicals cause allergic reaction Impetigo Pink, water-filled, raised lesions around the mouth caused by staphylococcus bacterial infection Psoriasis Cause is unknown but chronic Triggered by trauma, infection, stress Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.33 Skin Homeostatic Imbalances Burns Tissue damage and cell death caused by heat, electricity, UV radiation, or chemicals Nearly every body system is affected when skin is severely damaged Associated dangers Dehydration Electrolyte imbalance Circulatory shock Infection Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.34 Rules of Nines Way to determine the extent of burns Body is divided into 11 areas for quick estimation Each area represents about 9% Rule of nines Classified according to their severity (depth) Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.35 Severity of Burns First-degree burns Only epidermis is damaged Skin is red and swollen Partial-thickness burn that heals quickly Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.36 Severity of Burns Second degree burns Epidermis and upper dermis are damaged Skin is red with blisters Partial-thickness burn that heals w/o scar Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.37 Severity of Burns Third-degree burns Destroys entire skin layer Burn is gray-white or black Nerve endings destroyed so not painful Full-thickness burn that does not heal and grafting is necessary Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.38 Severity of Burns •Fourth-degree burns •Extend through the skin to injure muscle, ligaments, tendons, nerves, blood vessels, and bones •These burns always require medical treatment Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.39 Critical Burns Burns are considered critical if: Over 25% of body has second degree burns Over 10% of the body has third degree burns There are third degree burns of the face, hands, or feet Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.40 Skin Cancer Cancer – abnormal cell mass Two types Benign Does not spread (encapsulated) Malignant Metastasized (moves) to other parts of the body Skin cancer is the most common type of cancer Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.41 Skin Cancer Types Basal cell carcinoma Least malignant Most common type Arises from stratum basale that no longer makes keratin and stays in place Squamous cell carcinoma Arises from stratum spinosum Metastasizes to lymph nodes Early removal allows a good chance of cure Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.42 Skin Cancer Types Malignant melanoma Most deadly of skin cancers Cancer of melanocytes Metastasizes rapidly to lymph and blood vessels Detection uses ABCD rule Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.43 ABCD Rule A = Asymmetry Two sides of pigmented mole do not match B = Border irregularity Borders of mole are not smooth C = Color Different colors in pigmented area D = Diameter Spot is larger then 6 mm in diameter Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 4.44