The Integumentary System

  1. Integument
    -Largest organ- most visible/accessible organ
    -Surface area: 1.5-2m2
    -15-20% of total body weight
    -First line of defense enviroment
  2. Dead Skin
    • billions of tons of dust in atmosphere
    • -Shed about 50,000 cells every minute
  3. Integumentary System:
    • -Protection
    • -Temperature Regulation
    • -Excretion
    • -Vitamin D
    • -Sensations
  4. Integumentary System:

    • -Protects underlying tissues and organs
    • -Provides protection against UV coming from the sun
  5. Integumentary System:

    Temperature Regulation:
    • -Helps regulate body temperature
    • -Provides insulation to keep heat in
    • -Evaporative cooling to allow heat out
  6. Integumentary System:

    • -Removes waster products from the body
    • e.g. salts, water, and organic wastes by glands
  7. Integument

    Skin (cutaneous layer)= epidermis+dermis
  8. Integument
    Quick overview of Structure: SKIN

    1. Epidermis
    : Superficial layer of epithelial tissue
    2. Dermis: deep layer of connective tissue. Provides nourishment of epidermis & structural strength.
    3. Subcutaneous layer (hypodermis): Not technically part of the skin, it is loose connective tisseue that connects skin to underlying structures & provides insulation
  9. Integument
    Quick overview of Structure: SKIN

    Accessory structures:

    Originate in the dermis extend through the epidermis to skin surface:
    • 1. Hair
    • 2. Nails
    • 3. Glands
  10. What are the two layers of the Dermis?
    • 1. Papillary layer
    • 2. Reticular layer
  11. Epidermis
    • Avascular: nourished by diffusion from capillaries of the papillary layer of the dermis
    • Composed of cells arranged into layers or strata
    • Separated from dermis by basement membrane
  12. Thick vs. Thin skin refers to what skin layer?
    EPIDERMIS (the top)
  13. Thin or Thick skin: Most of our body surface?
    Thin (4 layers about as thick as a sandwich bag)
  14. Thick skin
    • 5 layers (strata)= 0.5-1mm thick
    • Covers palms of hands and soles of feet
    • Deep epidermal ridge patterns
    • Patterns increase surface area and provide friction
    • Produce fingerprints
  15. Thin or Thick Skin? Palms of hands
    Thick skin (produces our finger prints ....also on soles of feet)
  16. Structure of the Epidermis:

    The five strata of KERATIONCYTES in thick skin from basal lamina to free surface:
    • Stratum germinativum
    • Stratum spinosum
    • Stratum granulosum
    • Stratum lucidum
    • Stratum corneum
  17. Which of the following is ONLY found in thick skin?

    E. Stratum lucidum (clear thick skin covers stratum granulosum)
  18. Easy way to remember the 5 Epidermal layers:

    "Can Little Girls Speak German"

    from the most superficial to the deepest
    • Corneum (surface)
    • Lucidum
    • Granulosum
    • Spinosum
    • Germinativum (deepest layer)
  19. How many days does it take to go from germinativum to the corneum?
    15-30 days (bottom to top) keratinized cells stay in corneum for an additional 2 weeks before washing away held togher by desmosomes/shed in sheets
  20. Epidermis Layers: 4-5 Strata

    Stratum Corneum (surface)- disposable
    • 15-30 layers of dead keratinocytes
    • Thicker layer in thick skin
    • Strong, water resistant barrier
  21. Which of the following is a disposable strata?

    D. Stratum corneum (top layer remember CLGSG- top to bottom)
  22. Epidermis layers: 4-5 Strata

    Stratum Lucidum (waterproof) "clear"
    Thin keratinocyte layer (extra layer in THICK skin)
  23. Epidrmis Layers: 4-5 Strata

    Stratum Granulosum (strength) "grainy"
    • 3-5 layers/high keratin fiber and keratohyalin
    • kh: dense granules / aggregation and crosslinking of keratin
  24. Which of the following has aggregation and crosslinking of keratin?

    E. Stratum granulosum
  25. Epidermis Layers: 4-5 Strata
    Stratum spinosum (immunity) "spiny layer"
    • Langerhans cells: anti-microbial
    • 8-10 layers of keratinocytes
    • New daughter keratinocytes
  26. Which of the following is considered an immunity layer?

    A. Stratum spinosum
  27. Epidermis Layers: 4-5 Strata

    Stratum Germinativum/basale
    • Basal cells: Stem cell source of keratinocytes
    • -15 day journey to the top layer
    • Merkel Cells: Touch Receptor Cells
    • Melanocytes: secrete melanin (pigment)
  28. Touch receptor cells found in Stratum Germinativum
    Merkel Cells
  29. Cells that secrete melanin and are found in Stratum Germinativum
  30. Stem cell source of keratinocytes (found in Stratum Germinativum)
    Basal Cells
  31. Epidermis:

    Stratum Germinativum
    • The "germinative" layer
    • -Has many germinative (stem) cells or basal cells
    • -Attached to basal lamina by hemidesmosomes
    • -Forms a strong bond between epidermis and dermis
    • Forms epidermal ridges (eg fingerprints)
    • Dermal papillae (tiny mounds)
    • Increase the area of basal lamina
    • Stengthen attachment between epidermis and dermis
  32. What attaches the stratum germinativum to the basal lamina ?
  33. Which of the following forms a strong bond between epidermis and dermis?

    E. Stratum germinativum (deepest layer of the epidermis closests to the dermis)
  34. T/F Merkel Cells are found in hairy skin
    False!!! found in hairless skin (ohhhh and they respond to touch)
  35. What separates the epidermis from the dermis?
    basement membrane
  36. Dermis Overview:
    • 1. Gives structural stength. Connective Tissue with many fibers, fibroblasts, macrophages,. Some adipocytes and blood vessels
    • 2. Contain nerves, blood vessels, hair follicles, smooth muscles, glands and lymphatic vessels
    • 3. Sensory functions: pain, itch, tickle, temperature, touch and pressure
  37. 2 layers of the Dermis?
    • Papillary
    • Reticular
  38. Dermis:

    Papillary Layer (superficial layer... 1/5)
    • Consists of Areolar tissue with lots of elastic fibers
    • Dermal papillae, Capillary beds.
    • Fingerprints.
    • Whorls of ridges
    • Touch receptors (Meissner's)
    • Free nerve endings sensing pain
  39. Dermis:

    Reticular layer (deep<inner> , 4/5)
    • -Interwoven meshwork of DENSE IRREGULAR connective tissue
    • -Collagen and elastic fibers
    • -Also see seome adipose, hair follicles, nerves, oil glands, ducts of sweat glands, heat sensors.
  40. Cleavage <Tension> lines
    • Elastin and collagen fibers oriented in some directions more than in others
    • Important in surgery(if incision parallel to lines, there is less gapping, faster healing , less scar tissue)
  41. If skin is overstretched,______________ (stretch marks) occur
  42. Dermal Strength and Elasticity:

    Collagen Fibers
    • Give skin strength and resistance to stretching
    • Very strong and limit stretching to prevent damage to tissue
  43. Dermal Strength and Elasticity:

    • Elastic fiber that allows skin to stretch and then recoil back to normal length
    • Stretch marks are a sign that skin has been stretched beyond its capacity and recoil
    • Stretching of skin due to pregnancy or weight gain can exceed elastic limits of skin by causing damage to the dermis
  44. Dermal Strength and Elasticity:

    Sagging and Wrinkles:
    Result from permanent reduction in amount of elastin in dermis, mostly caused from aging, hormones, ultraviolet radiation (sun exposure)
  45. What gives skin strength and resistance to stretching?
    Collagen Fibers
  46. What allows skin to stretch and then recoild back to normal length?
    Elastic Fibers (like a rubberband)
  47. Reduction in amount of ___________ in dermis results in sagging and wrinkles
  48. What is a derivative of vitamin A that can be applied to the skin as a cream or gel that increases the blood flow to dermis and stimulates repair?
    Tretonin (Retin-A) .... decreases the rate of wrinkle formation and existing wrinkles become smaller

    • egg shaped
    • Detects light touch (i.e tactile corpuscle)
    • Located dermal papillae
    • Populated areas in fingertips, palms, soles, eyelids, tip of tongue & genitalia

    • Onion Shaped in cross section; have a lamellated appearance
    • Located deeper in reticular layer & subcutaneous lare
    • Detect Pressure
    • Populated in joints tendons, muscles, mammary glands, & external genitalia
  51. Meisnner's or Pacinian? Populated in joints tendons, muscles, mammary glands, & external genitalia
    Pacinian Corpuscle
  52. Meissner's or Pacinian? Detects Pressure
    Pacinian Corpuscle
  53. Meissner's or Pacinian? Located in dermal papillae
    Messner's Corpuscle

    not technically part of the integument
    Located deep in skin (beneath the dermis)-indistinct border
    Attaches skin to underlying structures
    Consists of loose connective tissue with collagen and elastic fibers
    Site of lipid storage and contains about 1/2 of body's fat
  55. Hypodermis

    • Energy source
    • Insulation
    • Padding
    • Blood reservoir (can hold 5-8% volume) superficial part has large veins& arteries
    • Can shunt blood for temperature regulation
  56. Another name for Subcutaneous tissue
    Hypodermis/Superficial Fascia
  57. Where is the site of cosmetic liposuction?
    Hypodermis (remember it contains 1/2 of the body's fat)
  58. Where is the site of subcutaneous injections with hypodermic needles?
    Hypodermis (aka SUBCUTANEOUS TISSUE)
  59. What are the TWO pigments that influence skin color?
    Melanin and Carotene

    • orange-yellow pigment (like a carrot)
    • found in orange vegetables (carrot)
    • accumulates in epidermal cells and fatty tissues of the dermis
    • can be converted to vitamin A

    • yellow-brown or black pigment
    • produced by melanocytes in stratum germinativum
    • manufactured from amno acid TYROSINE
    • package and store in transport vesicles
    • melanosomes transferred to keratinocytes
  62. What cells produce melanin?
  63. Melanocytes produce melanin in what layer of the epidermis?
    Stratum germinativum
  64. What amino acid manufactures melanin?
  65. Function of Melanocytes:

    Melanin protects skin from UV sun damage
    Ultraviolet radiation causes DNA mutations and burns that lead to cancer and wrinkles
  66. Skin pigmentation varies on individual based on location
    • 2 times more melanocytes on cheeks, forehead, nipples, genitalia
    • Can have increased rate of melanin production (eg freckles on light skin mean larger than average production)
  67. People of different races have essentially SAME NUMBER of MELANOCYTES but amount of melanin produced varies
    eg Albino individuals have a normal number of melanocytes but can't produce melanin
  68. Abnormal: VITILIGO
    loss of melanocytes (like MJ) ... theory is that it is an autoimmune disorder
  69. UV is good for the production of which vitamin?
    VITAMIN D!!!!
  70. Vitamin D production: UV (the good)
    • 1. Skin exposed to UV light produces cholecalciferol, which is modified in the liver and then in the kidneys to form calcitriol (active vitmin D)
    • 2. Vitamin D increases blood calcium levels by promoting calcium uptake from the small intestines, calcium released from bone and reduction of calcium loss from the kidneys
    • 3. Calcium functions from bone homeostatis ie. bone formation, growth, repair, and also nerve and muscle formation
  71. Rickets
    • Abnormal bone development in children & insufficient Vitamin D
    • Results if low sun exposure and or Vit D3 in diet
  72. Calcitrol can be absorbed through the intestinal walls, what are some of the sources?
    Dairy, liver, egg yolks, supplements (yay for ppl who live in cold climates or cover themselves)
  73. Accessory Skin Structures
    Sebaceous Glands (oil)
    • Located in Dermis
    • Holocrine glands (i.e. lysis and death of secretory cells
  74. Sebum:
    • an oily white substance rich in lipids (+ electrolytes+ proteins)
    • Most sebaceous glands empty into hair follicles (ie. connected by a duct to upper part of hair follicle.
    • Sebum lubricates hair and protects eidermis.
    • It functions to prvent drying (by conditioning skin) and may inhibit bacteria growth
  75. Exceptions to Sebacious Glands:
    • Some open directly to skin ie those located on lips, glands of eyelid, genitalia
    • Not associated with hair
  76. T/F Sebaceous Glands are MEROCRINE glands
    FALSE (they are holocrine-the secretory cell becomes swollen with vesicles and then ruptures)
  77. Accessory Structures:

    Sudoriferous (Sweat Glands) (MEROCRINE)
    • Merocrine (Eccrine) sweat glands; MOST COMMON
    • simple, coiled, tubularglands that open directly onto skin surface through sweat pore at surface
    • Widely distributed on body surface (more numerous than apocrine)
    • Especially on palms and soles (but absent from parts of lips and certain genital areas)
  78. T/F The skin contains TWO types of sweat (sudoriferous) glands
    TRUE (apocrine and merocrine)
  79. Aporcrine or Merocrine? Most common sweat gland
  80. T/F Aprocrine sweat glands rely on merocrine secretion method
    TRUE (doesnt make sense I KNOW)
  81. Accessory Structures:

    Sudoriferous Sweat Glands (APOCRINE)
    • Associated with hair
    • Ducts terminate in hair follicles
    • Help reduce friction between hair follicles and skin
    • Respond to stress/ emotions
    • Begin to function in purberty & continue throughout life
    • Located in arpits and groin
    • SMELLY!!!
  82. Aprocrine Sudoriferous Glands

    Produce organic substances that when fresh secretions are odorless but when acted upon by bacteria and becomes odiferous (rancid odor stinky)
  83. Merocrine/Apocrine? Produce a nutrient source for bacteria which intensify odor
  84. Merocrine Suoriferous Glands

    • 1. Cools skin surface (lowers body temp)
    • 2. Excretes water and elecrolytes
    • 3. Flushes micororganism &(has a peptide w/ antibiotic properites dermicidin) dilutes harmful chemicals from skin
  85. Merocrine Sudoriferous Glands

    Sensible Perspiration
    • Sweat is 99% Water, Salts (NaCl) and organic cmpd
    • Small amts of ammonia, urea, uric & lactic acid
  86. Quick Accessory Structure (GLANDS) summary:

    Merocrine sweat glands widely distributed across the body surface
    Sebaceous glands are located wherever there are hair follicles
    Apocrine sweat glands located in relatively restricted areas
  87. Mammary Glands
    • Modified apocrine sweat glands
    • Produce milk & function during lactation & pregnancy
  88. Ceruminous Glands
    • Modified swat glands
    • Location: external ear canal
    • Their secretion combines with sebum to produce EAR WAX (aka cerumen)
    • Function in combination w/ hair to prevent dirt & insects from entry
    • Also keep eardrum supple/flexible
  89. Hair is composed of keratinized dead cells that have been pushed to the surface
  90. Accessory Skin Structures: HAIR
    • -Produced by cells @ base of structures called hair follicles
    • -Hair follicles are tube like pockets of epidermal cells that extend into the dermis
    • -Individual hairs are actually large colums of dead cells that have filled with keratin
    • -Rapid growth at the base of the hair follicle in the hair root cause hair to grow longer
    • -Hair gets its color from melanin
    • -Hair follicles are in close contact w/ sebaceous glands (conditon hair)
    • -Hair protects and insulates body
    • -Most individual hairs grow for several years and then fall out
  91. HAIR

    Location: found EVERYWHERE except palms, soles, lips, nipples, & parts of the genitalia
    Function: Protects & insulates, Guard openings against particles & insects, sensitive to light touch
    Structure: Shaft protudes above skin surface: base of root is the hair bulb (internal matrix is source of hair)
  92. Hair

    3 Concentric layers
    • Medulla- central axis
    • Cortex- Forms bulk of hair
    • Cuticle- foms hair surface
    Arrector pili muscle contracts, pulling on the follicles and forcing the hair to stand erect
  94. Hair Growth
    • The hair bulb produces the hair in cycles w/ a growth stage and a resting stage
    • Growth: Cells added at base as hair elongates
    • Rest: Follicle shortens and holds hair in place
    • Rest, then hair falls out of follicle, new hair begins.
  95. Why is overheating a greater concern the older you get?
    • You have decreased sweat gland activity
    • Decrease vasularity of dermis
  96. Effects of aging
    Integument damage, infection, and cancer is a greater concern because:
    • Epidermal Thinning
    • Decreased # of langerhans cell
    • Decreased vitamin D3 production
    • Decreased glandular activity (oil and sweat)
    • Decreased melanocytes activity
    • Reduction in elastic fibers
    • Reduced blood supply & WBCs and other repair cells less active/responsive
  97. Dermatitis

    cause: inflmmation due to allergen or an irritant or toxin or may result from unknown immune problem.
    • Inflammation of Skin
    • Primarily involves papillary layer
    • Typically begins in part of skin exposed to infection or irritation
    • Maybe no discomfort or itchy or painful
    • Inflammation can spread amound integument
  98. Eczema (aka ATOPIC Dermatitis)
    Allergy: Overactive immune system: Recognizes something on skin as foregin, and immune cels destroy skin (eg pool water may cause a flare up)

    Triggers: Temperature changes, fungi, chemical irritants, grease, detergent or stress

    Treatment to prevent flare ups:
    • Create a barrier between skin and enviroment
    • ANTIhistamines to relieve itch
    • Hydrocortisone
    • Antibiots to get rid of bacteria
    • Emollent (VASELINE) or rich creams
  99. Eczema (aka ATOPIC DERMATITIS)

    Chronic Inflammatory Disease that needs to be managed. VERY itchy, known as the MESSY rash b/c its so itchy you SCRATCH.

    Up to 40% of all kids in US have eczema at some point
    NOT contagious
    Keep skin moist because dry skin cause flares
  100. Eczema:

    Hereditary or eviromental factors or BOTH

    Sebborheic dermatitis/eczema (cradle cap)
    • Particulary affects the sebum gland rich areas of skin
    • Dandruff common symptom
    • Strongest link: allergic response to yeast or other allergen
    • Shampoos with antifungals: Zinc pyrithione (head & shoulder), Selenium sulphide (selsun blue), ketoconazole (nizoral)
    • Tacroliumus inhibits T cells
    • Corticosteriods inhibit creation of inflammator mediators *prostaglandins
    • Antihistamine relieve itching
  101. Psoriasis
    • Chronic skin Disease/Inflammatory Disease
    • Stem cells in the stratum germinativum are unusually active&divide more frequently that normal
    • Skin cells multiply so fast (eg skin sheds every 3-4 days)
    • Strong genetic/hereditary component
    • Can be aggravated by stress and anxiety
    • Characterized by inflamed red areas, often develop silvery scales on places like elbows, kness, and lower back (keratinization is abnormal)
  102. Psoriasis

    Affects ~5% of ppl in US and ~2% of ppl worldwide
  103. Psoriasis: stem cells divide every 1.5 days
    Normal stem cells divide every 20 days

    Keritinization is abnormal & typically incomplete by the time outer layers are shed

    Affected areas: Red or Pink with losts of small silvery scales that continuously flake off
    20-30% of ppl have a genetic predisposition
  104. Dermatitis Psoriasis
    Caused by inflammation due to HYPERproliferation (due to Tcells)

    • Tcells migrate to epidermis
    • release cytokines (esp Tumor Necrosis Factor TNF)
    • TNF stimulates proliferation
    • Goal is to reduce inflammation and slow rapid growth and skin shedding:
    • Methotrexate: inhibits proliferation of keratinocytes, (anticancer drug that interrupts growth of cells, it is used for severe cases)
    • Immune suppressing meds such as topical corticosteroids
    • UV
    • Coal Tar makes skin more sennsitive to light
  106. SKIN cancer

    most common cancer in US
    Fastest increasing cancer in US

    3 main types:
    • Basal cell (most common)
    • Squamous cells
    • Melanoma (worst b/c mestastasize)
  107. The main difference between melanomas and other skin cancers is that melanoma can MESTASTASIZE (spread) to distant body sites including lungs, liver or brain
    • Melanoma most common cancer in young adults age 25-20
    • Among women age 30-35, incidence is exceeded only by breast cancer
    • Incidence increasing 4% annually, higher than any other cancer
    • On average, one melanoma death in the US per HOUR
  108. Skin Cancer:

    • Least malignant
    • Most common type
    • Arises from stratum baseal /straum germinativum
    • 2/3 appear areas receive chronic UV exposure
    • Genetic factors predispose
  109. Skin Cancer:

    Squamous cell carcinoma
    • Less common
    • Arises from stratum spinosum
    • Early removal allows a good chance of cure
  110. Squamous Cell Carcinoma

    Red or pink scaluy patches
    Sometimes wart-like that forms puss in middle
    Found on edge of ears, face, lips, mouth and hands
  111. Basal Cell Carcinoma

    Small, fleshy bumps
    Normally on ears, nose, neck, head
    Slow growing, doesnt mestastasize but can penetrate to bony areas that require more invasive surgery
    95% of patients with surgical removal live 5 years or LONGER
  112. Which of the following is the most common form of skin cancer?

    B. Basal call
  113. Which of the following is the least malignant form of skin cancer?

    B. Basal call
  114. Which of the following is the least common form of skin cancer?

    A. Squamous cell
  115. Which of the following arises from stratum spinosum?

    C. Squamous cell
  116. Malignant Melanoma
    • Most deadly of skin cancers
    • Cancer of melanocytes
    • New cases of melanoma has DOUBLED since 1973
    • 7th most common cancer in US
    • Begins in melanocytes
    • Metastasizes rapidly to lymph and blood vessels
  117. Malignant Melanoma

    Survival rate after 5 yr: 14% if found after metastasis
    99% if detected early
  118. Melanoma ABCDs
    • Asymmetry- 1/2 doesnt match the other 1/2 (irregular in shape, raised, may ooze or bleed)
    • Border- edges are ragged, notched, or blurred(border is indistinct&irregular)
    • Color- pigmentation is not uniform-shades of tan, brown or black are present (a mottled appearance)
    • Diameter- greater than 1/4 in. Any susdden or continuing increase in size is of special concern. (greater than 55mm isn diamter or area cover by eraser on a pencil is DANGEROUS)
  119. UV radiation can be dived into 2 ranges:
    • UVA (320-400nm)
    • UVB (290-320mm)
  120. UVA and UVB are both thought to initiate skin cancer

    Tanning salons advertise that UVA is safe (FALSE)
  121. Sunscreen

    As sale has risen so has skin cancer (protect again SUNBURN not skin cancer)
    Some protection against SCC but not BCC or Malignant Melanoma
    Ppl who use it have higher incidence of BCC
    Block or absorb UV
Card Set
The Integumentary System
Dr. Skacel IBHS The Integumentary System