Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Human Anatomy & Physiology SEVENTH EDITION Elaine N. Marieb Katja Hoehn PowerPoint ® Lecture Slides prepared by Vince Austin, Bluegrass Technical and Community College C H A P T E R 5 The Integumentary System

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Functions of the Integument  1. protects us from bacterial invasion  2. protects us from dessication  3. protects us from heat loss  4. protects us from UV radiation

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Skin (Integument)  Consists of three major regions  Epidermis – outermost superficial region  Dermis – middle region  Hypodermis (superficial fascia) – deepest region

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 5.1 Epidermis Dermis Hypodermis (superficial fascia) Hair root Hair shaft Pore Dermal papillae (papillary layer of dermis) Meissner's corpuscle Free nerve ending Reticular layer of dermis Sebaceous (oil) gland Arrector pili muscle Sensory nerve fiber Eccrine sweat gland Pacinian corpuscle Artery Vein Adipose tissue Hair follicle receptor (root hair plexus) Hair follicle Eccrine sweat gland

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Epidermis  4 major types of cells in the epidermis: a. Keratinocytes – produce keratin which protects the skin b. Melanocytes – protects the cell nuclei from UV radiation – gives us skin color c. Langerhans cells – ingest foreign substances d. Merkel cells – sensory receptor for touch

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Layers of the Epidermis Figure 5.2b

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Layers of the Epidermis  Stratum Basale – deepest layer next to dermis a. continual mitosis b. produces new keratinocytes and melanocytes

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Layers of the Epidermis  Stratum Spinosum a. Have filaments that function to resist tension and attach to the desmosomes b. Have Langerhans cells and melanin granules and spiky kerantinocytes

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Layers of the Epidermis  Stratum Granulosum a. Keratinocytes change to flattened shape b. Organelles disintegrate c. Granules which form keratin d. Granules which form a glycolipid waterproofing contained in extracellular space to slow water loss from epidermis e. No capillarity above this layer

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Layers of the Epidermis  Stratum Lucidum a. Clear flat dead keratinocytes b. Visible only in thick skin area of the body c. No present in think skin areas of the body

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Layers of the Epidermis  Stratum Corneum a. Outermost layer b. Protect against penetration and abrasion c. Consists of dead cells (dead skin and dandruff)

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Dermis  Contains fibroblasts (produces fibers); macrophages (destroy bacteria and worn cells); mast cells (detect foreign substances and initiate the inflammatory response); white blood cells (take part of the immune response)  Supplied with nerve, blood, and lymphatic vessels  Contain hair follicle, oil and sweat glands

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Dermis  Second major skin region containing strong, flexible connective tissue  Composed of two layers –  papillary  reticular

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Layers of the Dermis: Papillary Layer  Touch receptors  Fingerprints  Gripping of hands and feet  Contain Meissner’s corpuscles (touch)  Contain Pacinian corpuscles (pain)

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Layers of the Dermis: Reticular Layer  80% of the thickness of the skin  Collagen fibers in this layer add strength and resiliency to the skin  Elastin fibers provide stretch-recoil properties  Nourished by cutaneous plexus

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Hypodermis  Subcutaneous layer deep to the skin  Composed of adipose and areolar connective tissue

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Skin Color  Three pigments contribute to skin color  Melanin – yellow to reddish-brown to black pigment, responsible for dark skin colors  Freckles and pigmented moles – result from local accumulations of melanin  Carotene – yellow to orange pigment, most obvious in the palms and soles of the feet  Hemoglobin – reddish pigment responsible for the pinkish hue of the skin

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Sweat Glands (sudoriferous glands)  prevent overheating of the body  secrete cerumen and milk  Eccrine – found in palms, soles of the feet, and forehead  Apocrine – found in axillary and anogenital areas  Ceruminous glands – modified apocrine glands in external ear canal that secrete cerumen  Mammary glands – specialized sweat glands that secrete milk

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Sebaceous Glands  Soften skin when stimulated by hormones  Secrete an oily secretion called sebum  Whitehead, blackhead, seborrhea

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Hair (Pili)  dead keratinized cells produced by hair follicles  Regions are shaft and root  Contains hard keratin  Consists of a core called the medulla, a cortex, and an outermost cuticle  Pigmented by melanocytes at the base of the hair

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Shaft of Hair (Go to Microscope)  If shaft is flat and ribbon like (kinky)  If shaft is oval (silky and wavy)  If shaft is round (straight)  Locate medulla, cortex, cuticle  Look at the slides with beard hair (note the shape of the tip ends)  Pull a hair out by the root (observe the root tip)

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Hair Function and Distribution  Functions of hair include:  Helping to maintain warmth  Alerting the body to presence of insects on the skin  Guarding the scalp against physical trauma, heat loss, and sunlight

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Hair Follicle Figure 5.5c

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Types of Hair  Vellus – pale, fine body hair found in children and the adult female  Terminal – coarse, long hair of eyebrows, scalp, axillary, and pubic regions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Structure of a Nail  Scalelike modification of the epidermis on the distal, dorsal surface of fingers and toes Figure 5.6

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Functions of the Integumentary System  Protection  Body temperature regulation  Cutaneous sensation - touch and pain

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Protection- Physical Barriers Prevents bacterial invasion Provides waterproofing with glycolipids Does allow penetration of: a. O, CO2, Vitamins A,D,E,K and steroids b. Oleoresins (poison oak/ivy) c. Organic solvents (paint thinner, acetone) d. Salts and heavy metals (Pb,Hg) e. Drug agents

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Protection - Biological a. Langerhans cells – detect foreign substances b. Macrophages – viruses and bacteria c. DNA-conversion of radiation to heat

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Body Temperature Regulation  Constant secretion of sweat  Dilation of blood vessels and increased sweat production during excessive heat  Evaporation  Constriction of blood vessels and heat loss is slowed

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Metabolic Functions  Synthesis of vitamin D in dermal blood vessels – aids in Ca absorption from digestive system  Makes chemicals to aid liver function  Makes enzymes that deter wrinkles

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Functions of Skin  Blood reservoir – 5% of blood volume  Excretion – sweat (amonia, urea, uric acid)

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Skin Cancer  Most skin tumors are benign and do not metastasize  A crucial risk factor for nonmelanoma skin cancers is the disabling of the p53 gene  Newly developed skin lotions can fix damaged DNA

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Skin Cancer – 3 types 1. Basal cell carcinoma – least malignant and most common-stratum basale 2.Squamous cell carcinoma-stratum spinosum-most head,hands,can metastasize 3. Melanoma – cancer of melanocyts- most dangerous

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Skin Cancers Figure 5.7a–c

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Melanoma – ABCD rule  A: Asymmetry; the two sides of the pigmented area do not match  B: Border is irregular and exhibits indentations  C: Color (pigmented area) is black, brown, tan, and sometimes red or blue  D: Diameter is larger than 6 mm (size of a pencil eraser)

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Rule of Nines - Burns  Burns considered critical if:  Over 25% of the body has second-degree burns  Over 10% of the body has third-degree burns  There are third-degree burns on face, hands, or feet Volume of fluid lost extimated by percentage of body surface burned 11 body areas – each 9%

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Rule of Nines Figure 5.8a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Developmental Aspects of the Integument: Fetal  Epidermis develops from ectoderm  Dermis and hypodermis develop from mesoderm  Lanugo – downy coat of delicate hairs covering the fetus  Vernix caseosa – substance produced by sebaceous glands that protects the skin of the fetus in the amnion