A&P Chapter 5: Integumentary System

  1. Functions of cutaneous membrane and hypodermis:
    Protection, Excretion (urea), Thermoregulate, Synthesis of Vitamin D3, Storage (nutrients, and Detection of stimuli (pressure and heat).
  2. Cutaneous Membrane:
  3. Epidermis:
    superficial epithelium
  4. Dermis:
    underlying connective tissues
  5. Accessory Structures of the integumentary system:
    hair, nails, multicellular exocrine glands
  6. Subcutaneous Layer (hypodermis, superficial fascia):
    connective tissue, separates the integument from the deep fascia around the other organs (muscles, bones)
  7. Keratinocytes:
    body’s most abundant epithelial cell type, stratified squamous
  8. Thick Skin (Fig. 5-2c)
    palms and feet, more layers of cells
  9. Thin Skin (Fig. 5-2b)
    rest of the body, less layers of cells
  10. Five Layers of the Epidermis: (Fig. 5-4, Lab Text Fig. 7.2)
    • starting from the bottom up:
    • 1.Stratum Germinativum
    • 2.Stratum Spinosum
    • 3.Stratum Granulosum
    • 4.Stratum Lucidum
    • 5.Stratum Corneum
  11. Stratum Germinativum (Stratum basale) (Fig. 5-3)
    can receive nutrients that diffuse from the dermis, therefore has the energy for mitosis
  12. In the Stratum Germinativum are Epidermal Ridges (Fig.5-4)
    extend into the dermis, area of contact between dermis and epidermis. Epidermal ridges are unique to individuals, finger prints do not change over a life time
  13. In the Stratum Germinativum there are Dermal Papillae:
    dermal side of epidermal ridges
  14. In the Stratum Germinativum Basal Cells:
    germinative cells for regeneration, most abundant cell type in stratum germinativum
  15. In the Stratum Germinativum there are Merkel Cells:
    in areas that the skin does not contain hair, fine touch sensitive specialized epithelial cells
  16. In the Stratum Germinativum there are Melanocytes (Fig. 5-5):
    pigment producing cells that processes extend into stratum spinosum and injected melanosomes into nearby keratinocytes.
  17. Stratum Spinosum:
    ‘spiny layer’, daughter keratinocytes moving up and dividing, 8-10 cell layers thick
  18. In the Stratum Spinosum there are Langerhans Cells: defensive cells that phagocytize, digest, and present invader (bacteria or skin cancer cells)
  19. Stratum Granulosum:
    ‘grainy layer’, no more dividing, keratinocytes kick in and make lots of keratin, organelles disintegrate, cells get thinner, 3-5 cell layers thick
  20. In the Stratum Granulosum there is Keratin:
    a fibrous protein produced by keratinocytes
  21. In the Stratum Granulosum there is Keratohyalin:
    a protein that cross links keratin fibers and promote dehydration of the cell
  22. Stratum Lucidum:
    ‘clear layer’, only in thick skin areas, keratinocytes are flat and densely packed
  23. Stratum Corneum:
    exposed surface of the skin, 15-30 cell layers thick, water resistant, not water proof
  24. In the Stratum Corneum there is Keratinization (cornification):
    formation of protective superficial layers of keratinocytes filled with keratin
  25. In the Stratum Corneum there is Insensible Perspiration:
    evaporation of water from body (about 1 pint, 500 ml/ day)
  26. In the Stratum Corneum there is Sensible Perspiration:
    water loss due to active sweat glands for thermoregulation (cooling)
  27. Skin Color:
    dependent on epidermal pigmentation and dermal circulation
  28. Epidermal Pigmentation :
  29. Carotene:
    orange yellow pigment accumulates in epidermal cells. Carotene can be converted to vitamin A (carrots, squash rich with carotene)
  30. Melanin:
    brown black pigment produced by melanocytes from tyrosine residues
  31. Melanocytes (Fig. 5-5):
    in stratum germinativum (10-15% stratum germinativum cells are melanocytes). Melanocytes form and package melanin into melanosomes that are transferred through the melanocyte’s processes to keratinocytes. Race color is dependent on the amount of melanin produced not the number of melanocytes.
  32. Ultraviolet (UV) Radiation:
    nicks the DNA, causes replication errors, and mutations. Some UV radiation is good to convert vitamin D3 from an inactive to active form. Vitamin D3 deficiency can cause Rickets (Fig. 5-7)
  33. Dermal Circulation:
    • attributed to hemoglobin, blood pigment (O2 bou
    • nd bright red, without O2 bound dark red). ‘White with fright’ due to blood draining from dermis.
  34. Cyanosis:
    blue coloring due to oxygen deprived, evident in lips and beneath the nails
  35. Freckles:
    more melanin in a localized area
  36. Jaundice:
    Bile can not be excreted by liverso a yellow pigment accumulates in body fluids. In advance stages skin and the whites of the eyes turn yellow.
  37. Vililigo:
    autoimmune attack on healthy melanocytes
  38. Addison’s Disease:
    increased levels of adrenocorticotropin hormone (ACTH), ACTH similar to melanocyte stimulating hormone (MSH), skin turns bronze in color
  39. The Epidermis and Vitamin D3
    In the stratum germinativum and stratum spinosum a cholesterol related steroid is converted to Vitamin D3 (cholecalciferol) with the help of UV radiation.
  40. Vitamin D3 (cholecalciferol)
    goes to the liver and is converted to calcitriol precursor (2,5 hydroxy D3) and then gets further processed in the kidneys.
  41. Calcitriol:
    hormone produced by the kidneys that increases the intestinal absorption of calcium and phosphorus
  42. Epidermal Growth Factor (EGF):
    • peptide growth factor produced by salivary glands and glands in the duodenum
    • Functions: Promote mitotic divisions of germinative cells (Stratums germinativum and spinosum), accelerate the production of keratin in differentiating epidermal cells, stimulates epidermal development and repair, therapeutic use in burn victims (grow skin in culture, 300x area/ week).
  43. Drug Administration through Skin
    • Liposomes with DNA fragments for skin cancer antigens
    • Transdermal administration with patch application for nitroglycerin, nicotine, and hormones.
  44. The Dermis
    Accessory structures extend into the dermis, plus dermis contains lymph vessels, blood vessels, and nerve fibers
  45. Dermal Organization
    • 1. Papillary Layer
    • 2. Reticular Layer
  46. Papillary Layer:
    superficial dermis, areolar connective tissue with blood vessels and sensory nerves
  47. Reticular Layer:
    deeper dermis, dense irregular connective tissue
  48. Wrinkles
    Collagen fibers are strong and resistant to stretching, can be bent and twisted. Elastic fibers go back and recoil. As we age we lose water, have decreased hormone levels, plus the cumulative effects of UV exposure takes a toll on our skin. Increase of age decrease amount of elastin in the dermis, we get wrinkles and sagging of the skin.
  49. Stretch Marks
    due to excessive weight gain (pregnancy) and the skin does not snap back
  50. Skin Turgor:
    flexibility and resilience of skin
  51. Tretinoin (Retin-ATM):
    Vitamin A derivative that increases blood flow to the dermis, therefore expediates dermal repair and decrease rate of wrinkle formation.
  52. Lines of Cleavage (Fig. 5-8)
    bundles of fibers that run parallel to a line to resist a common directional force. Surgeons use lines of cleavage for the orientation of the incision. Wound will heal faster with limited scar tissue built up if incision is made parallel to the line of cleavage.
  53. The Dermal Blood Supply (Fig. 5-9)
    supplies epidermis (via diffusion), dermis, and subdermis with nutrients and waste disposal
  54. Problems with Dermal Circulation
    • Ulcer
    • Decubitis ulcers
    • Necrosis
    • Birth marks
    • Contusions
    • Cavernous Hemangiomas
    • Capillary Hemangiomas
  55. Ulcer:
    local shedding epithelium
  56. Decubitis ulcers (bedsores, Fig. 7.3 of lab text)
    circulation restrictions (pressure of body against bed) starves epidermis and dermis. Prevent by repositioning body constantly.
  57. Necrosis:
    tissue death
  58. Birthmarks:
    dermal blood vessel tumors before birth
  59. Capillary Hemangiomas (strawberry mark):
    type of bithmark in dermis, increase in size after birth and then reduce in size as toddler grows
  60. Cavernous Hemangiomas:
    type of birthmark which has port wine stains, large blood vessels in dermis, remove by laser surgery (stork bite – on nape of neck or back of head, visible through adulthood; angel kisses – stains on eyelids and foreheads, disappear by the age of 2 years)
  61. Contusions (Black and Blues)
    rupture dermal blood vessels
  62. Innervation of the Skin
  63. Tactile (Merkel’s) discs (Fig. 7.2 in lab text)
    Merkel cell (Stratum Germinativum) + sensory terminals (in dermis) that detect light touch in epidermis.
  64. Tactile (Meissner’s) Corpuscles:
    in dermal papillae, sensitve to light touch
  65. Lamellated (Pacinian) Corpuscles:
    in reticular layer of dermis, sensitive to deep pressure and vibration
  66. Dermatitis:
    inflammation of the skin that involves primarily the papillary layer
  67. Contact dermatitis:
    occurs in response to strong chemical irritants, produces an itchy rash that may spread to other areas, example: poison ivy.
  68. Eczema:
    dermatitis that can be triggered by temperature changes, fungi, chemical irritants, greases, detergents or stress. Hereditary factors environmental factors, or both can promote its development.
  69. Diaper Rash:
    localized dermatitis caused by a combination of moisture, irritating chemicals from fecal or urinary wastes, and flourishing microorganisms.
  70. Urticaria (hives):
    extensive allergic response to a food, a drug, an insect bite, infection, stress, or some other stimulus
  71. The Subcutaneous Layer
    not part of the integument but stabilizes position of integument, permits independent movement of skin (pinch a fold of skin)
  72. Hypodermis (subcutaneous layer):
    comprised of areolar connective tissue, adipose connective tissue, blood vessels (rich blood reservoir)
  73. Subcutaneous Fat:
    Babies – baby fat needed to reduce heat loss and shock absorber, Men – on arms, neck, bum, and lower back, and Women – breasts, bum, thighs, hips; adult distribution is different due to hormonal influences. Fat in excess increases risks of diabetes, stroke, and other diseases.
  74. Liposuction
    tears and rips tissue and subcutaneous fat from body with a uniform applied vacuum (contusions, painful recovery, uneven surfaces, baggy skin, risks with anesthesia, bleeding, fluid loss). Fat will come back if behaviors do not change.
  75. Blood Reservoir for subcutaneous injections,
    subcutaneous layer so heavily vascularized, avenue for injections because substances will be taken through general circulation
  76. Hair follicles
    produce hair (Fig. 5-10)
  77. Hair Structure (Fig. 5-10)
    • 1. Hair Root:
    • 2. Hair Shaft:
    • 3. Cuticle:
    • 4. Hair Papilla:
    • 5. Hair Bulb:
  78. Hair
    is non-living material, 2.5 million hairs /body, 75% not on head (only 500,000 hairs on your head)
  79. Hair Root:
    anchors hair into the skin
  80. Hair Shaft:
    part we see on surface
  81. Cuticle:
    outer surface of shaft, dead keratinized cell shell
  82. Hair Papilla:
    base of hair follicle, connective tissue with blood vessels and nerves
  83. Hair Bulb:
    epithelia cells around the hair papilla
  84. Types of Hair
    • lanugo
    • Velous
    • Terminal
  85. Lanugo:
    3 month embryo, shed before birth
  86. Velous:
    peach fuzz located over most of the body’s surface. Velous hair can turn to terminal hair based hormones circulating
  87. Terminal:
    heavier, more pigmented hair on head, eyelashes, eyebrows etc.
  88. Hair Color
    dependent on structure of melanosomes and pigment variation at hair papillae – genetically determined and environmentally induced
  89. Functions of Hair
    protection from UV radiation, insulates head, guard orifices
  90. Root Hair Plexus:
    nerve tissue around each hair follicle
  91. Arrector Pili:
    smooth muscle attaches to each hair to raise hair, in response to fear, temperature (goose bumps), autonomic regulation
  92. Growth and Replacement of Hair
    • 1. Hair Growth Cycle
    • 2. Club Hair:
  93. Hair Growth Cycle
    scalp hair lasts about 2-5 years; absorbs nutrients and toxins as it grows
  94. Club Hair:
    hair of an inactive hair follicle, hair is shed at the end of its growth cycle
  95. Glands in the Skin
    two exocrine glands
  96. Sebaceous Glands (Fig. 5-11)
    oil glands, holocrine mode of secretion
  97. Sebum:
    mixture of triglycerides, cholesterol, proteins, and electrolytes that inhibit bacterial growth as well as lubricate skin and hair shaft
  98. Sebaceous Follicles:
    sebaceous glands not associated with hair follicles; vent directly to the skin. Present on face, back, and chest
  99. Problems with Sebaceous Glands:
    blocked gland can become a boil
  100. Acne:
    large sebaceous glands are prone to infection (pimple forms) Sex hormones increase secretion of sebum and then the gland may plug housing bacteria with it
  101. Seborrheic Dermatitis (cradle cap, dandruff)
    inflammation around sebaceous gland
  102. Sweat Glands
    • Apocrine Sweat Glands
    • Merocrine (Eccrine) Sweat Glands
  103. Apocrine Sweat Glands: (fig. 5-12a)
    tubular glands located in armpits and groin. Produce a viscous smelly secretion into the hair follicles starting at puberty (merocrine mode of secretion)
  104. Myoepithelial Cells:
    contract and squeeze gland to discharge the secretion
  105. Merocrine (Eccrine) Sweat Glands: (Fig. 5-12b)
    • produce 99% water secretion (pH 4-6.8) with some salt; merocrine sweat glands are all over the body and in high number
    • Functions: Cooling, Excreting, Defensive.
  106. Mammary Glands:
    apocrine mode of secretion, Oxytocin and Prolactin stimulate activity
  107. Ceruminous Glands:
    ear sweat glands
  108. Cerumen:
    ear wax. Ear wax plus ear hair trap particles from going further
  109. Control of Glandular Secretions:
    autonomic nervous system control over sebaceous and apocrine sweat glands. Activation is all sebaceous or all apocrine glands, not gland at a time
  110. Nails (Fig. 5-13)
    help you grab things better, protect fingers and toes
  111. Nail Body:
    visible portion of nail
  112. Nail Bed:
    underlying epidermis under nail body
  113. Nail Root:
    where nail production occurs
  114. Cuticle:
    skin area that covers nail
  115. Local Control of the Integumentary Function
  116. Injury and Repair (Fig. 5-14)
    • Scab
    • Granulation tissue
    • Scar tissue
    • keloid
  117. Scab:
    temporary surface of fibrin clot, restores integrity and blocks invasion
  118. Granulation Tissue:
    repair crew combination of fibroblasts, blood clot, and capillary network
  119. Scar Tissue:
    fibrous tissue replacement over damaged area
  120. Keloid:
    thickened area of scar tissue, raised, and has shiny epidermal surface
  121. Aging and the Integumentary System
    As we age, skin gets thinner, slower healing, decreased stem cell activity, decreased gland activity, decreased vitamin D3 activation, decreased hair follicle production, and decreased melanin production in hair (thinner hair, thinning hair)
  122. Burns and Grafts
    About 10,000 people in the US die a year as a result of burns
  123. First Degree (sun burn)
    First few layers of the epidermis are affected
  124. Erythema:
    redness, inflammation on skin surface
  125. Second Degree:
    entire epidermis affected, and some dermis involved result in blister, pain, swelling
  126. Third Degree:
    full thickness burn, epidermis, dermis, hypodermis are destroyed along with accessory structures
  127. Skin Graft:
    from cadaver or self (cultured with epidermal growth factor)
  128. Synthetic Skin:
    plastic epidermis with dermis collagen (cow skin) and ground cartilage (sharks)
  129. If person has > 80% of body surface burned (3rd degree burns), then they have 50:50 chance of survival (Fig.5-17). At risk due to
    • •fluid balance and electrolyte balance is upset
    • •open to infection
    • •no thermoregulation without eccrine glands
  130. Skin Cancers
    • Basal Cell Carcinoma
    • Squamous Cell Carcinoma
    • Malignant Melanoma
  131. Basal Cell Carcinoma (Fig. 5-6a): malignant cancer starts in stratum germinativum
    • •most common skin cancer
    • •2/3 basal cell carcinoma appear in areas chronic exposure of UV
    • •some people have a genetic predisposition
    • •metastasis to other tissues is not likely
  132. Squamous Cell Carcinoma
    • •prevented by sunscreen
    • •squamous cell carcinoma appears in areas exposed to UV
    • •metastasis to other tissues is not likely
    • •less common than basal cell carcinoma
  133. Malignant Melanoma (Fig. 5-6b)
    • * deadly, 75% of skin cancer deaths
    • * melanocytes metastasize through lymphatics
  134. * Four Signs to help Detect Melanoma (A, B, C, D)
    • A asymmetry, irregular shape, ooze or bleed
    • B border unclear, irregular and/or notched
    • C color, many colors (tan, brown, pink, red, black, white, blue)
    • D diameter, >5mm (0.2 inches), more than a pencil eraser
  135. General Information about skin cancer:
    • 164,000 Americans diagnosed/yr (3x more than 30 years ago)
    • 8,600 American/ year die from skin cancer
    • Fair skinned people more prone to skin cancers, not enough melanin to shield them from the damaging effects of UV radiation
    • SPF > 15 absorb, scatter, and/or reflect UV rays. The more SPF the more chemicals. Need to block both UVA and UVB
    • Tanning beds pose the same risk as sun exposure!!!!
    • Lag time from time of UV exposure to early signs of skin cancer about 15-20 years
  136. ______1. Shila was warming up chicken noodle soup for her children. She accidentally spilt some soup on her hand. She cooled the burn with cold water but she still had painful blisters form at the site of the burn. What kind of burn did Shila have on her hand?
    second degree
  137. ______2. The purpose of a scab is to
    block invasion
  138. ______3. Hello, I’m a ‘wet sweat’ gland. Ninety nine percent of my secretion is water. Who am I?
    Merocrine (eccrine) sweat gland
  139. ______4. This is the kind of hair we have in our nostrils.
  140. ______5. What is not part of the cutaneous membrane?
  141. ______6. What layer of the epidermis do the langerhan cells reside?
    Stratum Spinosum
  142. ______7. The difference between a person with albinism and a person with black skin is
    The person with albinism has the same number of melanocytes as the person with black skin but the melanocytes of the person with albinism does not produce melanin.
  143. ______8. Hello I result from a dermal circulation problem. I am a hole in the skin in an area where a person has kept their body weight on for a long period of time. Who am I?
    Decubitis ulcer
  144. ______9. I’m a layer in the epidermis evident only in thick skin areas (such as on the soles of feet, the palms of hands, and all over New Yorkers ). Who am I?
    Stratum Lucidum
  145. ______10. Melanocytes and merkel cells reside in this epidermal layer.
    Stratum Germinativum
  146. Dry skin
    is a result of a decrease in the activity of the sebaceous glands in the skin.
  147. Wrinkles
    are a result of a decrease in elastic fibers in the dermis and a decrease in thickness of the subcutaneous layer of the skin.
  148. Age spots
    are due to an increase of activity melanocytes in localized areas (such as the hands and face, areas exposed to UV) or melanosomes clumping in these areas and a decrease of melanocytes in other areas of the body. Causes of age spots are UV exposure, age, and genetics.
  149. Gray or white hairs
    occur in aging as a result of a decrease or a lack of melanin production in the hair. The number of melanocytes may also decrease.
  150. Prone to heat prostration (heat exhaustion)
    In the elderly blood flow to the skin is decreased. Therefore the skin can’t dissipate heat from the body as well as it used to (when vessels close to the surface vasodilate to radiate heat from the body). In addition the elderly have less sweat gland activity so cooling the body is hard to do.
Card Set
A&P Chapter 5: Integumentary System
A&P Chapter 5: Integumentary System