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Integumentary System


Integumentary System This body system connects to the other systems in many ways!! See handout pg 45. This system consists of the skin and its accessory organs, hair ... – PowerPoint PPT presentation

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Title: Integumentary System

Integumentary System
  • This body system connects to the other systems in
    many ways!! See handout pg 45.
  • This system consists of the skin and its
    accessory organs, hair, nails, and cutaneous

Functions of the Integumentary System
  • 1. Resistance to trauma and infection
  • (epidermal cells have lots of KERATIN (protein)
  • 2. Barrier to liquids
  • 3. Vitamin D synthesis
  • 4. Sensation
  • Thermoregulation
  • 6. Social functions ?

Layers of the skin
  • Epidermis is the top five layers of skin, and
    contains five different types of cells
  • 1A. Dead cells (keratinocytes)
  • 1B. Living Keratinocytes most of the epidermal
    cells, they
  • produce keratin and use UV light to
    convert a steroid to pre-vitamin D
  • Stratum Corneum
  • 2. Dendritic cells (Langerhans cells)
    microphages that fight
  • toxins, microbes, and other pathogens that
    penetrate the
  • skin, (Immune alarm) Stratum Spinosum
  • 3. Tactile cells (Merkel cells) are receptors
    for touch Stratum Basale
  • 4. Stem Cells they go through mitosis to
    produce keratinocytes
  • Stratum Basale
  • 5. Melanocytes produce melanin that reacts to
    sun light to increase
  • sun burn protection Stratum Basale
  • See table 6.1 on page 194

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2nd layer of skin Dermis
  • Dermis lies below epidermis, has large amounts
    of fibrous connective tissue.
  • Composed mainly of collagen, elastic, and
    reticular fibers.
  • The connective tissue in this layer contains
    blood vessels, sweat glands, hair follicles, nail
    roots, sebaceous glands, smooth
    muscles,(Piloerector), pressure receptors and
    nerve endings

3rd Layer of the Skin Hypodermis
  • The hypodermis is often called the superficial
  • The fascia contains large amounts of adipose
  • ( subcutaneous fat), connective tissue, blood
  • Adipose tissue pads the body, is a thermal
    insulation and energy store and is the preferred
    injection site due to it vascular rate
  • Connective tissue binds the skin to the
    underlying tissues

Skin Color
  • Skin color is determined by amount of
  • melanin produced by melanocytes.
  • There are basically 2 colors
  • Eumelanin Brown Black
  • Pheomelanin Red/Yellow (sulfur containing)
  • Other factors are hemoglobin (red/pink hues) and
  • carotene
    (yellow/orangein veggies)

Skin Color can indicate disease or disorders
  • 1. Cyanosisblueness due to O2 deficiency
  • 2. Erythemabnormal redness, blush, sunburn
  • 3. Pallor---- ash, pale, too little blood flow,
    dermal collagen shows through
  • 4. Albanismlack of melanin..genetic recessive
  • 5. Jaundice yellowing of skin due to high
    levels of billirubin, hemoglobin break down
  • 6. Bronzinggolden brown, Addison Disease, lack
    of glucocorticoid hormone.
  • 7. Hematomabruising, purplish, clotted blood
    showing through.

Types of Skin Markings
  • Friction Ridges markings on fingertips, form
    during fetal development
  • Flexion Lines Lines on digits, palms, wrists,
  • Freckles flat melanized patches of skin that
    vary with heredity and sun exposure
  • Moles same as freckle but elevated
  • Hemangiomas birth marks caused by begnin tumors
    of dermal blood capillaries

Accessories of the skin Hair, Nails, and
  • Hair and Nails are composed of mostly dead
    keratinized cells.
  • Skin (stratum corneum has soft keritin)
  • Hair and Nails made of more compact, hard
    keritin, cross linked between keritin moelcules.

Cross section of a hair
Structures of hair
Basis of hair color and texture
  • See page 199
  • Hair grows from the hair matrix just above the
    hair bulb.
  • The hair bulb is near vascular connective tissue
    which provides hair with its nutrients.

Nail structure
  • What are the Accessory Structures Nails?
  • Nail body
  • Dense mass of keratinized cells
  • Nail bed
  • Nail root
  • Cuticle (eponychium)
  • Lunula

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Glands of the skin
  • The skin has 5 types of Glands
  • 1. Merocrine Sweat Glands
  • 2. Apocrine Sweat Glands
  • 3. Sebaceous Glands
  • 4. Ceruminous glands
  • 5. Mammary Glands

Sweat Glands
  • Merocrine (eccrine)
  • Most numerous
  • Produces watery 99 perspiration for cooling
  • 3-4X106 all over
  • Palms, soles, forehead
  • pH 4-6
  • Tubular gland with twisted coil
  • Narrow lumen, opens at pore on skin
  • Apocrine
  • Occur in groin, anal, axilla, beard area.
  • Produces thicker soln. with fatty acids
  • Are scent glands
  • Large lumen, opens to hair follicle

Sebaceous Glands
  • Produce an oily secretion called SEBUM
  • Flask shaped, located higher up in dermis
  • Short ducts opening to hair follicles
  • Keeps skin and hair from becoming dry
  • (brushing hair spreads this)
  • Lanolin in moisturizers is sheep sebum

Ceruminous Glands
  • Found only in external ear canal
  • Secretion combines with sebum dead epithelial
    cells to make ear wax CERUMEN
  • Waterproofs the ear canal and is anti-bacterial

Mammary Glands
  • Milk producing glands in female breasts
  • Are modified apocrine glands which produce richer
  • For summary see chart 6.2 on page 203

Skin Disorderssee chart 6.3
  • What are the Effects of UV Radiation?
  • Beneficial effect
  • Activates synthesis of vitamin D3
  • Harmful effects
  • Sun burn
  • Wrinkles, premature aging
  • Malignant melanoma
  • Basal cell carcinoma

Skin Cancer
  • Cancer rapid mitotic division of cells caused by
    a trigger environmental, genetic
  • Skin cancer is caused by exposure to UV rays.
    There are three types named for tissue affected
  • 1. Basal carcinoma
  • most common,
  • easiest to remove.
  • Appears as a red shiny bump that enlarges with
    depressed center

  • 2. Squamous Cell Carcinoma
  • found usually on scalp, ears, lip, back of hands.
  • Has red scaly appearance with concave center.
  • High survival rate with early detection,
  • will metastasize to lymph nodes highly lethal

  • 3. Malignant melanoma
  • most deadly
  • arises in melanocytes in moles.
  • Fast to metastasize
  • lethal without immediate treatment

Recognizing Malignant Melanoma
  • A Asymmetry
  • B Border irregularity
  • C Color (brown, black, tan, red, purple)
  • D Diameter (6mm)

Burns and Healing
  • Burns Leading cause in accidental death, death
    results from fluid loss and the toxic effect of
  • First degree found in only epidermis, epidermis
    turns red, edema and pain, heals in a few days

  • Second degree or partial-thickness burns due to
    damage only in top of dermis layers, has blisters
    can scar and takes about 2 weeks to heal
  • Third degree or total thickness burns, turns
    black, skin can only grow from sides of damaged
    area so grafts are needed, debridement must occur
    in 24 hours, then toxic

Healing and Repair on injury to skin
  • What are the Four Stages in Skin Healing?
  • 1. Inflammation
  • Blood flow increases
  • Phagocytes attracted
  • 2. Scab formation
  • 3. Cell division and migration
  • 4. Scar formation

Bleeding occurs at the site of injury immediately
after the injury, and mast cells in the region
trigger an inflammatory response.
After several hours, a scab has formed and cells
of the stratum germinativum are migrating along
the edges of the wound. Phagocytic cells are
removing debris, and more of these cells are
arriving with the enhanced circulationin the
area. Clotting around the edgesof the affected
area partially isolatesthe region.
After several weeks, the scab has been shed, and
the epidermis is complete. A shallow depression
marks the injury site, but fibroblasts in the
dermis continue to create scar tissue that will
gradually elevate the overlying epidermis
One week after the injury, the scab has been
undermined by epidermal cells migrating over the
meshwork produced by fibroblast activity.
Phagocytic activity around the site has almost
ended, and the fibrin clot is disintegrating.
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