Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 6 Lecture PowerPoint Integumentary System

2 6.1: Introduction Two or more kinds of tissues grouped together and performing specialized functions constitutes an organ. The skin and its various structures make up the integumentary system.

3 6.2: Skin and Its Tissues Composed of several tissue types Maintains homeostasis Protective covering Retards water loss Regulates body temperature Houses sensory receptors Contains immune system cells Synthesizes chemicals (such as vit D) Excretes small amounts of wastes

4 Layers of Skin (2) Epidermis Dermis Subcutaneous layer aka hypodermis beneath dermis some also call it the superficial fascia not part of the skin Stratified squamous epithelium Dense irregular connective tissue Adipose tissue Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © The McGraw-Hill Companies, Inc./Al Telser, photographer

5 (a) Hair shaft Epidermis Hair follicle (b) Sebaceous gland Dermis Sweat Epidermis Dermis Hair shaft Sweat gland pore Capillary Stratum corneum Stratum basale Dermal papilla Arrector pili muscle Lamellated (Pacinian) corpuscle Basement membrane Sebaceous gland Hair follicle Sweat gland Nerve cell process Adipose tissue Blood vessels Muscle layer Sweat gland duct Subcutaneous layer TTactile (Meissner’s) corpuscle Epidermis Lacks blood vessels Keratinized Thickest on palms and soles ( mm) Melanocytes provide melanin Rests on basement membrane Stratified squamous epithelia Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. b: © Victor Eroschenko

6 Epidermis There are five (5) layers of the epidermis: stratum corneum stratum lucidum stratum granulosum stratum spinosum stratum basale Stratum corneum Stratum lucidum Stratum granulosum Stratum spinosum Stratum basale Basement membrane Dermis Dermal papilla (a)(b) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. b: © The McGraw-Hill Companies, Inc./Al Telser, photographer

7 Epidermis Genetic Factors Varying amounts of melanin Varying size of melanin granules Albinos lack melanin Environmental Factors Sunlight UV light from sunlamps X-rays Darkens melanin Physiological Factors Dilation of dermal blood vessels Constriction of dermal blood vessels Accumulation of carotene Jaundice Cyanosis Heredity and environment determine skin color

8 Dermis Contains dermal papillae Binds epidermis to underlying tissues Irregular dense connective tissue On average mm thick Muscle cells – arrector pili Nerve cell processes Specialized sensory receptors Blood vessels Hair follicles Glands (a) Sweat Epidermis Dermis Hair shaft Sweat gland pore Capillary Stratum corneum Stratum basale Dermal papilla Arrector pili muscle Lamellated (Pacinian) corpuscle Basement membrane Sebaceous gland Hair follicle Sweat gland Nerve cell process Adipose tissue Blood vessels Muscle layer Sweat gland duct SubcutaneousSubcutaneous layer Tactile (Meissner’s) corpuscle Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

9 Dermis Papillary layer thin superficial dermal papillae here loose areolar CT Reticular layer 80% of dermis dense irregular CT There are actually two (2) layers to the dermis: (a) Sweat Epidermis Dermis Hair shaft Sweat gland pore Capillary Stratum corneum Stratum basale Dermal papilla Arrector pili muscle Lamellated (Pacinian) corpuscle Basement membrane Sebaceous gland Hair follicle Sweat gland Nerve cell process Adipose tissue Blood vessels Muscle layer Sweat gland duct SubcutaneousSubcutaneous layer Tactile (Meissner’s) corpuscle Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

10 Subcutaneous Layer Aka hypodermis Loose connective tissue and … Adipose tissue are present Insulates Major blood vessels present (a) Sweat Epidermis Dermis Hair shaft Sweat gland pore Capillary Stratum corneum Stratum basale Dermal papilla Arrector pili muscle Lamellated (Pacinian) corpuscle Basement membrane Sebaceous gland Hair follicle Sweat gland Nerve cell process Adipose tissue Blood vessels Muscle layer Sweat gland duct Subcutaneous layer Tactile (Meissner’s) corpuscle Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

11 6.3: Accessory Structures of the Skin Accessory structures of the skin originate from the epidermis and include: Hair follicles Nails Skin glands

12 Hair Follicles Epidermal cells Tube-like depression Extends into dermis Three (3) parts: Hair root Hair shaft Hair papilla Melanin Arrector pili muscle (a) Hair shaft Pore Hair root (keratinized cells) Arrector pili muscle Sebaceous gland Hair follicle Region of cell division Hair papilla Eccrine sweat gland DermalDermal blood vessels Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

13 Nails Protective coverings Three (3) parts: Nail plate Nail bed Lunula Nail bedNail plateLunula Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

14 Sebaceous Glands Usually associated with hair follicles Holocrine glands Secrete sebum (oil) Absent on palms and soles Hair Sebaceous gland Hair follicle Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Per H. Kjeldsen

15 Sweat Glands Aka sudoriferous glands Widespread in skin Originates in deeper dermis or hypodermis Eccrine glands Apocrine glands Ceruminous glands Mammary glands Dermal papilla Sebaceous gland Duct Hair shaft Hair follicle Eccrine sweat gland Apocrine sweat gland Pore Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

16 6.4: Regulation of Body Temperature Regulation of body temperature is vitally important because even slight shifts can disrupt metabolic reactions.

17 Regulation of Body Temperature If body temperature continues to drop, control center signals muscles to contract involuntarily. too high too low Normal body temperature 37°C (98.6°F) Control center Hypothalamus detects the deviation from the set point and signals effector organs. Control center Hypothalamus detects the deviation from the set point and signals effector organs. Stimulus Body temperature rises above normal. Effectors Dermal blood vessels dilate and sweat glands secrete. Response Body heat is lost to surroundings, temperature drops toward normal. Effectors Dermal blood vessels constrict and sweat glands remain inactive. Effectors Dermal blood vessels constrict and sweat glands remain inactive. Response Body heat is conserved, temperature rises toward normal. Stimulus Body temperature drops below normal. Receptors Thermoreceptors send signals to the control center. Receptors Thermoreceptors send signals to the control center. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

18 Heat Production and Loss Heat is a product of cellular metabolism The most active body cells are the heat producers and include: Skeletal muscle Cardiac muscle Cells of certain glands such as the liver The primary means of heat loss is radiation Also there is conduction, convection and evaporation

19 Problems in Temperature Regulation Hyperthermia – abnormally high body temperature Hypothermia – abnormally low body temperature

20 6.5: Healing of Wounds and Burns Inflammation is a normal response to injury or stress. Blood vessels in affected tissues dilate and become more permeable, allowing fluids to leak into the damaged tissues. Inflammed skin may become: Reddened Swollen Warm Painful

21 Healing of Cuts (a)(b) (f)(g) (c)(d)(e) Scar tissue Fibroblasts Scar tissue Blood cells Site of injury Scab Blood clot Scab Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

22 Types of Burns First degree burn – superficial, partial-thickness Second degree burn – deep, partial-thickness Third degree burn – full-thickness

23 Rule of Nines for Adults Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Anterior trunk 18% Posterior trunk 18% Anterior upper extremities 9% Posterior upper extremities 9% Posterior lower extremities 18% Perineum 1% Anterior and posterior upper extremities 18% Anterior and posterior lower extremities 36% 100% Anterior and posterior trunk 36% Anterior and posterior head and neck 9% Anterior head and neck 4 1 / 2 % Posterior head and neck 4 1 / 2 % Anterior lower extremities 18% 9% 41/2%41/2% 41/2%41/2%41/2%41/2% 41/2%41/2%41/2%41/2% 41/2%41/2%

24 6.6: Lifespan Changes Skin becomes scaly Age spots appear Epidermis thins Dermis becomes reduced Loss of fat Wrinkling Sagging Sebaceous glands secrete less oil Melanin production slows Hair thins Number of hair follicles decreases Nail growth becomes impaired Sensory receptors decline Body temperature unable to be controlled Diminished ability to activate Vitamin D