Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Human Anatomy & Physiology, Sixth Edition Elaine N. Marieb PowerPoint ® Lecture Slides prepared by Vince Austin, University of Kentucky 5 The Integumentary System

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Functions of Skin Function of Integumentary System A. Regulation of Body Temperature B. Protection from Dehydration and Infection C. Respond to Temperature, Pressure, Pain D. Excretion of Water, Salts, Urea (nitrogenous waste) E. Synthesis Vitamin D (essential for Ca + P absorption) F. First Defensive Barrier of Immune Response

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Overview of Structure Structure of Integumentary System A. Epidermis (epithilial tissue) 1. stratum corneum(superficial) 2. stratum lucidum 3. stratum granulosum 4. stratum spinosom 5. stratum basale(deep) B. Dermis (connective tissue) 1. papillary layer (region) 2. reticular layer (region)

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Skin (Integument) Figure 5.1

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Epidermis Structure of Epidermis (epithilial tissue) A. Different Cells of Epidermis 1. keratinocyte - produce protein "keratin" (structure) 2. Merkel’s cells - serve as touch receptors 2. melanocyte - produce "melanin" (pigment) 3. nonpigmented granular dendrocytes a. Langerhan's cells - assist in immunity b. Granstein cells - assist in immunity

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Stratum Corneum 1. stratified sqamous epithilium rows of dead keratinized cells 3. keratinization occurs as cells rise from below 4. protects against light, heat, bacteria, chemicals 5. most superficial layer of epidermis

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Layers of the Epidermis

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Statum Lucidum 1. present only in thick areas (palms, feet) 2. contain clear substance called eleidin 3. eleidin eventually changes into keratin at surface

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Stratum Granulosum 1. cells from lower layers begin to die here 2. contain granules with keratohyalin 3. keratohyalin is precursor to eleidin and keratin

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Stratum Spinosum rows of polyhedral shaped cells 2. contain spine-like projections ("spinosum")

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Statum Basale (Stratum Germinativum) (germination) 1. deepest layer of the epidermis 2. single layer of cuboidal-columnar shaped cells 3. origin of all cells of epidermis through mitosis 4. origin of cells for sweat-oil glands and hair

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Structure of Dermis Structure of the Dermis (connective tissue) A. Overall Features 1. thick in some areas, thinner in others 2. contains blood supply, nerves, glands, hair follicle

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings B. Papillary Layer (Region) 1. loose connective tissue - much "elastin" 2. dermal papillae cause ridges in the epidermis above 3. Meissner's corpuscles - sense organ for touch 4. small capillaries supply O 2 + nutrients

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings C. Reticular Layer (Region) 1. dense, irregular connective tissue "collagen" 2. collagen fibers interlace in net-like fashion 3. contains: adipose, hair follicle, nerves, glands 4. subcutaneous layer attaches skin to tissue below a. Paccinian corpuscles - sense pressure change

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Hypodermis  Subcutaneous layer deep to the skin  Composed of adipose and areolar connective tissue

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Skin Color A. Melanin - pigment made in melanocytes 1. in basale and spinosum layers of epidermis 2. melanoblasts -> melanocytes in stratum basale 3. darkness due to melanin quantity (not cell #) 4. albinism - inability to produce melanin 5. vitligo - patchy loss of melanocytes 6. freckles - patchy concentration of melanocytes 7. UV light causes: tyrosine --> melanin production

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings B. Carotene 1. in stratum corneum and fatty areas of dermis 2. melanin + carotene = yellowish color

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings C. Other Colors 1. pink (Caucasian) - lack of pigment, capillaries 2. blue (cyanosis) - lack of oxygen in blood 3. yellow (jaundice) - liver disorder, protein release

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Glands A. Sebaceous Glands (oil glands) 1. found all over the body 2. generally connected to hair follicles 3. simple branched acinar glands 4. sebum - mixture fat, protein, cholesterol, salt 5. prevent dessication, keep skin soft, anti-bacterial a. infected gland - acne, blackheads

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings B. Sudoriferous Glands (sweat glands) 1. Apocrine Sweat Glands a. simple branched tubular glands b. only in axilla (arm pit), pubic + areole areas c. in dermis, duct opens into a hair follicle 2. Eccrine Sweat Glands a. simple coiled tubular glands b. all over the body c. subcutaneous, opens onto epidermal surface

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings 3. Perspiration (sweat) a. mixture of water, salt, urea, ammonia, acids b. eliminates waste and heat

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings C. Ceruminous Glands 1. simple coiled tubular glands 2. in the external auditory meatus (canal) 3. cerumen - wax-like substance, prevents entry

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Hair A. Shaft - projects above surface of epidermis 1. medulla - polyhedral cells with eleidin 2. cortex - elongated cells with/out pigment 3. cuticle - outermost layer, like shingles on roof

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings B. Root - below epidermis, penetrates into the dermis C. Hair Follicle - at the base a a single hair 1. external root sheath - basale and spinosum extension 2. internal root sheath - internal hair cell layers 3. bulb - base of hair cell 4. papilla - in the bulb, provides nourishment for hair 5. matrix - origin of new hair cells

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Hair Follicle Figure 5.6c

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Hair Follicle Figure 5.6a

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings D. arrector pili - smooth muscle, cause hair to rise E. hair root plexuses - nerve bundle responds to touch

Copyright © 2004 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 © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Hair Thinning and Baldness  Alopecia – hair thinning in both sexes  True, or frank, baldness  Genetically determined and sex-influenced condition  Male pattern baldness – caused by follicular response to DHT

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Skin Cancer  Most skin tumors are benign and do not metastasize  A crucial risk factor for non-melanoma skin cancers is the disabling of the p53 gene  Newly developed skin lotions can fix damaged DNA

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Skin Cancer The three major types of skin cancer are:  Basal cell carcinoma  Squamous cell carcinoma  Melanoma

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Basal Cell Carcinoma  Least malignant and most common skin cancer  Stratum basale cells proliferate and invade the dermis and hypodermis  Slow growing and do not often metastasize  Can be cured by surgical excision in 99% of the cases

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Squamous Cell Carcinoma  Arises from keratinocytes of stratum spinosum  Arise most often on scalp, ears, and lower lip  Grows rapidly and metastasizes if not removed  Prognosis is good if treated by radiation therapy or removed surgically

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Melanoma Cancer of melanocytes is the most dangerous type of skin cancer because it is:  Highly metastatic  Resistant to chemotherapy

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Melanoma Melanomas have these characteristics (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 © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Melanoma  Treated by wide surgical excision accompanied by immunotherapy  Chance of survival is poor if the lesion is over 4 mm thick

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Burns First-degree – only the epidermis is damaged  Symptoms include localized redness, swelling, and pain Second-degree – epidermis and upper regions of dermis are damaged  Symptoms mimic first degree burns, but blisters also appear Third-degree – entire thickness of the skin is damaged  Burned area appears gray-white, cherry red, or black; there is no initial edema or pain (since nerve endings are destroyed)

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Rule of Nines Estimates the severity of 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

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Rule of Nines Figure 5.8a

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Skin and hair become oilier and acne may appear  Skin shows the effects of cumulative environmental assaults around age 30  Scaling and dermatitis become more common Developmental Aspects of the Integument: Adolescent to Adult

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Epidermal replacement of cells slows and skin becomes thinner  Skin becomes dry and itchy  Subcutaneous fat layer diminishes, leading to intolerance of cold  Decreased elasticity and loss of subcutaneous tissue leads to wrinkles  Decreased numbers of melanocytes and Langerhans’ cells increase the risk of skin cancer Developmental Aspects of the Integument: Old Age