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Dr. B Ch 04_lecture_presentation
- 1. © 2012 Pearson Education, Inc. 4 The Integumentary System PowerPoint® Lecture Presentations prepared by Steven Bassett Southeast Community College Lincoln, Nebraska
- 2. Introduction • The integumentary system is composed of: • Skin • Hair • Nails • Sweat glands • Oil glands • Mammary glands © 2012 Pearson Education, Inc.
- 3. Introduction • The skin is the most visible organ of the body • Clinicians can tell a lot about the overall health of the body by examining the skin • Skin is capable of repair even after serious damage because of containing stem cells persist both in epidermis and dermis. © 2012 Pearson Education, Inc.
- 4. Integumentary Structure and Function • Cutaneous membrane • Epidermis • Dermis • Accessory structures • Hair follicles • Exocrine glands • Nails © 2012 Pearson Education, Inc.
- 5. Figure 4.1 Functional Organization of the Integumentary System Integumentary System • Thermoregulation • Excretion • Synthesis of vitamin D3 • Sensory information © 2012 Pearson Education, Inc. Cutaneous Membrane Accessory Structures Epidermis Dermis Papillary Layer Reticular Layer Hair Follicles Exocrine Glands Nails • Physical protection from environmental hazards • Synthesis and storage of lipid reserves • Coordination of immune response to pathogens and cancers in skin • Protects dermis from trauma,chemicals • Controls skin permeability, prevents water loss • Prevents entry of pathogens • Synthesizes vitamin D3 • Sensory receptors detect touch, pressure, pain, and temperature • Coordinates immune response to pathogens and skin cancers • Nourishes and supports epidermis • Restricts spread of pathogens penetrating epidermis • Stores lipid reserves • Attaches skin to deeper tissues • Sensory receptors detect touch, pressure, pain, vibration, and temperature • Blood vessels assist in thermoregulation • Produce hairs that protect skull • Produce hairs that provide delicate touch sensations on general body surface • Assist in thermoregulation • Excrete wastes • Lubricate epidermis • Protect and support tips of fingers and toes
- 6. Figure 4.1 Functional Organization of the Integumentary System (Part 1 of 2) Cutaneous Membrane © 2012 Pearson Education, Inc. Epidermis • Protects dermis from trauma,chemicals • Controls skin permeability, prevents water loss • Prevents entry of pathogens • Synthesizes vitamin D3 • Sensory receptors detect touch, pressure, pain, and temperature • Coordinates immune response to pathogens and skin cancers Dermis Papillary Layer Reticular Layer • Nourishes and supports epidermis • Restricts spread of pathogens penetrating epidermis • Stores lipid reserves • Attaches skin to deeper tissues • Sensory receptors detect touch, pressure, paid, vibration, and temperature • Blood vessels assist in thermoregulation
- 7. Figure 4.1 Functional Organization of the Integumentary System (Part 2 of 2) Accessory Structures © 2012 Pearson Education, Inc. Hair Follicles Exocrine Glands Nails • Produce hairs that protect skull • Produce hairs that provide delicate touch sensations on general body surface • Assist in thermoregulation • Excrete wastes • Lubricate epidermis • Protect and support tips of fingers and toes
- 8. Integumentary Structure and Function • Functions include: • Physical protection • Regulation of body temperature • Excretion of products (secretion) • Synthesis of products (nutrition) • Sensation • Immune defense © 2012 Pearson Education, Inc.
- 9. Integumentary Structure and Function • Skin (cutaneous membrane) is made of two divisions • Epidermis • Dermis • Hypodermis (subcutaneous layer) is deep to the dermis. This layer separates the skin from deep fasciae • Accessory structures • Hair, nails, exocrine glands © 2012 Pearson Education, Inc.
- 10. Figure 4.2 Components of the Integumentary System Cutaneous Membrane Epidermis © 2012 Pearson Education, Inc. Accessory Structures Dermis Papillary layer Reticular layer Subcutaneous layer (hypodermis) Hair shaft Pore of sweat gland duct Tactile corpuscle Sebaceous gland Arrector pili muscle Sweat gland duct Hair follicle Lamellated corpuscle Nerve fibers Sweat gland Fat Artery Vein Cutaneous plexus
- 11. The Epidermis • There are four cell types found in the epidermis • Keratinocytes • Produces a tough protein called keratin • the most abundant cells in the epidermis. • Melanocytes • Pigment cells located deep in the epidermis • Produce melanin (skin color) • Merkel cells • Sensory cells • They send their free nerve endings into the epidermis, which are very sensitive to gentle touch. • Langerhans cells • Fixed macrophages © 2012 Pearson Education, Inc.
- 12. The Epidermis • Layers of the Epidermis • Stratum basale (stratum germinativum) • Deepest layer • Stratum spinosum • Stratum granulosum • Stratum lucidum • Stratum corneum • Most superficial layer © 2012 Pearson Education, Inc.
- 13. Figure 4.3 The Structure of the Epidermis © 2012 Pearson Education, Inc. Surface Stratum corneum Stratum lucidum Stratum granulosum Stratum spinosum Stratum basale Basal lamina Dermis Epidermis of thick skin LM ´ 225
- 14. Table 4.1 Epidermal Layers © 2012 Pearson Education, Inc.
- 15. The Epidermis • Epidermal ridges • Stratum germinativum forms epidermal ridges • Ridges (dermal papillae) extend into the dermis • Creates ridges we call fingerprints © 2012 Pearson Education, Inc.
- 16. Figure 4.4ab Thin and Thick Skin Epidermis Epidermal ridge Dermal papilla Dermis © 2012 Pearson Education, Inc. Stratum corneum Basal lamina Dermis Thin skin covers most of the exposed body surface. (During sectioning the stratum corneum has pulled away from the rest of the epidermis.) The basic organization of the epidermis. The thickness of the epidermis, especially the thickness of the stratum corneum, changes radically depending on the location sampled. LM ´ 240
- 17. Figure 4.5 The Epidermal Ridges of Thick Skin © 2012 Pearson Education, Inc. Pores of sweat gland ducts Epidermal ridge SEM ´ 25
- 18. The Epidermis • Skin color • Due to: • Dermal blood supply • Thickness of stratum corneum • Various concentrations of carotene and melanin © 2012 Pearson Education, Inc.
- 19. Figure 4.6 Melanocytes © 2012 Pearson Education, Inc. Thin skin LM ´ 600 Melanocytes in stratum basale Melanin pigment Basal lamina Melanosome Keratinocyte Melanin pigment Melanocyte Basal lamina This micrograph indicates the location and orientation of melanocytes in the stratum basale of a dark-skinned person. Melanocytes produce and store melanin.
- 20. The Dermis • The dermis consists of two layers • Papillary layer • Superficial dermis • Reticular layer • Deep dermis © 2012 Pearson Education, Inc.
- 21. The Dermis • Papillary layer (details) • Consists of: • Dermal papillae • Capillaries • Nerve axons © 2012 Pearson Education, Inc.
- 22. The Dermis • Reticular layer (details) • Consists of: • Interwoven network of dense irregular connective tissue • Hair follicles • Sweat glands • Sebaceous glands © 2012 Pearson Education, Inc.
- 23. Figure 4.2 Components of the Integumentary System Cutaneous Membrane Epidermis © 2012 Pearson Education, Inc. Accessory Structures Dermis Papillary layer Reticular layer Subcutaneous layer (hypodermis) Hair shaft Pore of sweat gland duct Tactile corpuscle Sebaceous gland Arrector pili muscle Sweat gland duct Hair follicle Lamellated corpuscle Nerve fibers Sweat gland Fat Artery Vein Cutaneous plexus
- 24. Figure 4.7a The Structure of the Dermis and the Subcutaneous Layer Dermal papillae Papillary layer Reticular layer Cutaneous plexus Adipocytes © 2012 Pearson Education, Inc. Papillary plexus Epidermal ridges Fi Papillary layer of dermis SEM ´ 649 The papillary layer of the dermis consists of loose connective tissue that contains numerous blood vessels (not visible), fibers (Fi), and macrophages (not visible). Open spaces, such as those marked by asterisks, would be filled with fluid ground substance
- 25. Figure 4.7b The Structure of the Dermis and the Subcutaneous Layer Dermal papillae Papillary layer Reticular layer Cutaneous plexus Adipocytes © 2012 Pearson Education, Inc. Papillary plexus Epidermal ridges Reticular layer of dermis SEM ´ 1340 The reticular layer of the dermis contains dense, irregular connective tissue.
- 26. Accessory Structures • Hair • Made of keratin 98% of the 5 million hairs on the body are not on the head. The fine hairs grown on the fetus body is called Lanugo. • Hair follicles Hair follicles are the organs that form the hairs. © 2012 Pearson Education, Inc.
- 27. Figure 4.9a Accessory Structures of the Skin © 2012 Pearson Education, Inc. Exposed shaft A diagrammatic view of a single hair follicle Sebaceous gland Arrector pili muscle Connective tissue sheath Hair bulb Hair papilla Hair shaft Boundary between hair shaft and hair root Hair root of hair
- 28. Figure 4.9b Accessory Structures of the Skin Epidermis Dermis © 2012 Pearson Education, Inc. Arrector pili muscle Sebaceous gland Hair shaft Hair follicle, cross section Hair Glassy membrane External root sheath Connective tissue sheath of hair follicle Cortex A light micrograph showing the sectional appearance of the skin of the scalp. Note the abundance of hair follicles and the way they extend into the dermis. Subcutaneous adipose tissue Medulla Papilla Scalp, sectional view LM ´ 66 Hair bulb
- 29. Accessory Structures • Glands in the skin • Eccrine glands or Merocrine glands: • The most abundant and widely distributed sweat glands that regulate body temperature. • Sebaceous glands: • Often associated with hair follicles. This is true also with Apocrine sweat glands that connect to the hair follicle to access to the surface of the skin. © 2012 Pearson Education, Inc.
- 30. Figure 4.12 A Classification of Exocrine Glands in the Skin © 2012 Pearson Education, Inc. Exocrine Glands Sebaceous Glands Sweat Glands Typical Sebaceous Glands Sebaceous Follicles Apocrine Sweat Glands Merocrine Sweat Glands Ceruminous Glands Mammary Glands • Assist in thermoregulation • Excrete wastes • Lubricate epidermis • Secrete oily lipid (sebum) that coats hair shaft and epidermis • Provide lubrication and antibacterial action types consist of Secrete into hair follicles Secrete onto skin surface • Produce watery solution by merocrine secretion • Flush epidermal surface • Perform other special functions types • Limited distribution (axillae, groin, nipples) • Produce a viscous secretion of complex composition • Possible function in communication • Strongly influenced by hormones • Widespread • Produce thin secretions, mostly water • Merocrine secretion mechanism • Controlled primarily by nervous system • Important in thermoregulation and excretion • Some antibacterial action special apocrine glands Secrete waxy cerumen into external ear canal Apocrine glands specialized for milk production
- 31. Figure 4.13 Sebaceous Glands and Follicles Epidermis Dermis Subcutaneous layer Sebaceous follicle © 2012 Pearson Education, Inc. Sebaceous gland Lumen (hair removed) Wall of hair follicle Basal lamina Discharge of sebum Lumen Breakdown of cell walls Mitosis and growth Germinative Sebaceous gland cells LM ´ 150
- 32. Accessory Structures • Sweat glands • Mammary glands • A special type of apocrine gland • Produce milk under the control of hormones from the pituitary gland • Ceruminous glands • A special type of apocrine gland • Found only in the ear canal • Produce cerumen (ear wax) • Provide minimal protection associated with the ear © 2012 Pearson Education, Inc.
- 33. Figure 4.15c Structure of a Nail Eponychium © 2012 Pearson Education, Inc. Phalanx Proximal nail fold Nail root Lunula Nail body Hyponychium Epidermis Dermis Longitudinal section
- 34. Aging and the Integumentary System • Epidermis becomes thinner • Dermis becomes thinner • Number of Langerhans’ cells decreases • Vitamin D production declines • Melanocyte activity declines • Glandular activity declines • Hair follicles stop functioning • Skin repair slows down Mechanical stress can trigger stem cell divisions resulting in calluses. Regeneration occurs after damage. The inability to completely heal after severe damage may result in acellular scar tissue. © 2012 Pearson Education, Inc.
- 35. Figure 4.16 The Skin during the Aging Process © 2012 Pearson Education, Inc. Fewer Melanocytes Fewer Active Follicles Thinner, sparse hairs • Pale skin • Reduced tolerance for sun exposure Reduced Skin Repair Decreased Immunity Skin repairs proceed more slowly. The number of dendritic cells decreases to about 50 percent of levels seen at maturity (roughly age 21). Thin Epidermis • Slow repairs • Decreased vitamin D production • Reduced number of Langerhans cells Reduced Sweat Gland Activity Tendency to overheat Changes in Distribution of Dry Epidermis Reduced Blood Supply Thin Dermis Fat and Hair Due to reductions in sex hormone levels Reduction in sebaceous and sweat gland activity • Slow healing • Reduced ability to lose heat Sagging and wrinkling due to fiber loss