Integumentary System

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Chapter 6

• Integumentary System

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Membranes

• Four Major types of membranes
• Serous Lines body cavities that lack openings
• Mucous Line cavities and tubes that open to the
  outside
• Synovial inner lining of joints
• Cutaneous skin

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Skin Organs

• Skin Largest organ of the body
• Skin derivatives
• Hair follicles
• Nails
• Sweat glands
• Sebacious glands

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Functions

• Protection
• UV radiation
• Barrier to keep outside things out and inside
  things in
• Cushions of fat to protect bones
• From water loss
• Regulation
• Body temperature
• Water balance
• Electrolyte balance
• Sensory and communication to alert us to the
  environment
• Excretion
• Absorption
• Energy storage
• Synthesis of Vitamin D and calcium metabolism
• Small blood reservoir
• Immunity and Defense

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Structure of the Skin
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Structure of the Epidermis

• Basement Membrane seperates Epidermis from Dermis
• Stratum Germinativum (Basale)
• Mitotic Cells that push cells up and away from
  blood supply
• Stratum Spinosum
• Living skin cells active
• Some mitosis
• Stratum Granulosum
• Keratin production
• Cell begin to die
• Stratum Lucidum
• Found only on soles of feet and palms of hands
• Stratum Corneum
• Mechanical barrier region
• Sluffed off

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Skin Color

• Largely due to Melanin which is produced by
  melanocytes located in connective tissue below
  the epidermis.
• Melanocytes transfer pigment to epidermal cells.
  (cytocrine secretion)
• Differences in skin color result from differences
  in the amount of melanin produced and in the size
  and location of pigment granules
• Sun can influence skin color along with UV lamps
  and xrays
• Blood in the dermis can make a person look
  pinkish in color when it is oxygenated.
  (blushing)
• Cyanosis blood oxygen concentration low and skin
  appears bluish.

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Skin Color Disorders

• Vitiligo not enough melanin is produced in
  certain areas of the body. Results in patches of
  white skin showing through

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Skin Color Disorders

• AlbininismInherited disorder in which a person
  lacks pigmentation.
• White hair
• Pink eyes
• Pale white skin
• Problems with vision

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Structure of the Dermis

• Function is to bind epidermis to underlying
  tissues.
• Dense connective tissue
• Dermal blood vessels supply skin with nutrients
  and regulate body temperature
• Nerve fibers and receptors are found throughout
  the dermis to detect changes in environment

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Structure of the Dermis

• Two Layers
• Papillary Layer
• Creates Finger Print
• Contains sensory receptors for light touch
  meissners corpuscles
• Reticular Layer
• Hair
• Exocrine Glands
• Oil
• Sweat
• Sebacious

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Skin Derivatives

• Hair Follicle
• Hair is found everywhere except for palms of
  hands and soles of feet
• Congenital generalized hypertrichosis
• Hair Shaft exits pore
• Hair bulb vessels found in this region
• Papilla brings nerves to hair
• As cells in root divide older cells are pushed
  out, die and are keratinized
• Arrector Pili Muscle pulls hair up and causes
  goose bumps
• Hair color melanin

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Skin Derivatives

• Types of Hair
• Lanugo
• Fine silky, fetal hair,
• Usually seen on premature babies
• Angora
• Grows continuously
• Scalp
• Face of male
• Definitive
• Grows to a certain length
• Most common type of hair
• Eyelashes, pubic region, eyebrows, and armpit
  hair.

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Hair Testing for Drugs

• Drugs taken in by a person are metabolized and
  broken down.
• After 5 days the hair will contain trapped broken
  down forms of the drugs in the hair
• Can be detectable for at least 90 days.
• Can be used to test for marijuana, cocaine,
  heroin, and PCP as well as prescription drugs

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Skin derivatives

• Nails
• Formed from compressed outer layer of stratum
  corneum
• Hardness due to keratin
• Function protect fingers and toes
• Consists of body, free border and attached border
• Nail Bed where the nail rest is stratum
  spinosum
• Lunula half moon shaped region near base of
  nail.

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Accessory Structures of the Dermis

• Exocrine Glands
• Modified Sweat Gland
• Mammary glands for secretion of milk
• Three Types
• Sebacious Glands
• Sebum oily material that to waterproof hair and
  skin
• Bacteria love to feed on sebum
• Apocrine Glands
• Associated with hair
• Appear during puberty
• Found in axillary and pubic regions
• Produces white material called Malodorous
• Eccrine Glands
• Not associated with hair
• Not malodorous

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Acne

• When the trapped sebum and bacteria stay below
  the skin surface, a whitehead is formed.
• A blackhead occurs when the trapped sebum and
  bacteria open to the surface and turn black due
  to melanin, the skin's pigment.
• Can last for long periods of time because it
  takes awhile to get to the surface

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ACNE
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Bed Sores

• Pressure Ulcers
• Develop in people who have been confined to bed
  for extensive periods of time
• Skins blood supply in certain areas is cut off
  causing death of cells

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Skin Cancer

• Actinic Keratosis Precursor to skin cancer
• Appears as a scaly and crusty and often
  recognized by touch
• Treatments cryosurgery, topical medications, or
  chemical peels

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Skin Cancer

• Caused by sun exposure or exposure to UV
  radiation (tanning beds)
• Forms of Skin Cancer
• Basal Cell Carcinoma
• Squamous Cell Carcinoma
• Melanoma
• Early warning signs (ABCDs)
• A Asymmetry
• B Border unevenness
• C Coloration
• D Diameter (larger than pencil eraser)