Integumentary System

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Integumentary System

• A Brief Overview

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Integumentary System

• Skin, hair and nails

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Skin Layers

• Epidermis, dermis, hypodermis

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Epidermis

• Outer layer
• Thin
• Made of epithelial cells
• Constant cell division pushes cells upwards.
  Cells die off in 2-4 weeks
• Keratin (protein) enters and hardens
• Palms, soles of feet have lots!!

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Skin Colors

• Skin color variations result from proteins in the
  epidermis
• Melanin
• Carotene
• Hemoglobin

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Skin Colors

• Melanin produced by melanocytes
• Melanocytes about equal in all people
• Greater melanin results in darker skin color
• Absence of melanin referred to as albinism

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Skin Color

• Carotene
• from beta-carotene
• Gives skin a yellowish color
• Color lightens as carotene breaks down

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Skin Color

• Hemoglobin
• Protein in blood
• Capillaries in skin dilate allowing more blood to
  flow to surface
• Gives skin a pinkish/reddish appearance
• Goes away when capillaries contract

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Dermis

• Below epidermis
• Thicker
• Contains blood vessels, nerves
• Connective tissue
• Has projections into epidermis to anchor it
  causes spiraling patterns
• fingerprints

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Hypodermis

• Below dermis
• (also called subcutaneous layer)
• Fat stored in adipose tissue
• Provides protection from shock
• -noticeable near kidneys

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Accessory Organs

• Hair
• Covers most of body
• Grows from hair follicle
• Life span is about 3-5 months
• Erector muscle makes hair stand up when cold

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Accessory Organs

• Nails
• Keratinized cells
• Parts of nail
• Nail bed
• Nail plate
• Lunula
• White portion

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Accessory Organs

• Glands
• Sebaceous Glands
• Secrete sebum (oil) into hair follicle
• Lubricates and waterproofs hair and skin
• When these glands dont work
• Whiteheads and blackheads form
• Bacteria in follicle produces red pimple

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Accessory Organs

• Glands
• Sweat Glands
• Large numbers all over body
• Two types
• Apocrine excrete sweat into hair react to
  stress
• Eccrine excrete sweat onto skin cooling
• Mammory glands are modified sweat glands located
  within the breasts produce milk

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Skin Model Showing Glands
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Skin Functions

• Protection
• From trauma
• From bacterial infection
• From pathogens (killed by acidic sweat)
• From dehydration and over hydration
• Skin retains and repels water

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Skin Functions

• Sensory Reception
• Receptors in dermis for
• Heat
• Cold
• Pain
• Pressure

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Skin Functions

• Synthesis of Vitamin D
• Molecules exposed to UV rays turn into vitamin D
• Vitamin D converts into a hormone (calcitronin)
  in kidneys
• Regulates calcium and phosphate levels
• Prevents rickets

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Skin Functions

• Regulation of Body Temperature
• Too Hot!!
• Blood flow through dermis increases
• More blood flows closer to skin and releases heat
  to environment
• Sweat glands produce more sweat
• Sweat evaporates cooling

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Skin Functions

• Regulation of Body Temperature
• Too Cold!!
• Blood flow through dermis decreases
• Heat is kept closer to internal organs
• Sweat gland production decreases

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Skin Disorders

• Acne, athletes foot, exzema, psoriasis,
  dandruff, moles, rosacia, warts
• Annoying, but not life threatening
• Treated with creams or antibiotics

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Skin Cancer

• Squamous Cell Carcinoma
• Basal Cell Carcinoma
• Can usually be surgically treated

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Skin Cancer

• Malignant Melanoma
• Serious- can lead to death
• Resembles a mole dark spot
• Occurs in light skinned people from constant
  exposure to sun

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Signs of Melanomas

• http//www.skincancerguide.ca/downloads/EarlySigns
  .mov
• ABCD method for pigmented skin
• A (most early melanomas are asymmetrical)
• B (borders of melanomas are uneven)
• C (color varied shades of brown, tan, or black
  are often the first sign of melanoma)
• D (diameter early melanomas tend to grow larger
  than common moles).

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ABCDs of Skin Cancer
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ABCDs of Skin Cancer
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Your Skin Phototype

• How likely are you to burn?
• Types I, II, and III have greater risk of
  developing skin cancers

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Burns

• Skin burns result from
• Heat- water, fire, surfaces
• Chemicals- acids, bases
• Electrical sources
• Radiation (UV and others)

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Skin Burn Severity

• 1st degree only epidermis is affected
• 2nd degree all of epidermis and part of dermis
  are affected
• 3rd degree all of the tissues (epidermis and
  dermis) are destroyed

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Rule of the Nines

• Body is divided into 11 sections
• Head, left arm, right arm, chest, abdomen, upper
  back, lower back, right thigh, left thigh, right
  leg below knee, left leg below knee
• Each section takes about 9 of bodys skin to
  cover it (totalling about 99)
• The other 1 of skin covers genital area

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Rule of the Nines

• Add up all areas of body that are burned badly
  enough to blister (2nd or 3rd degree burns).
• Ex If left arm and chest are burned badly, that
  equals 18. If face is the only part burned, it
  is about half of the head, so about 4.5.
• Used in the field to determine where to take
  patient for treatment (burn center or hospital)

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Healing

• Injured skin usually heals itself.
• Many events cascade to result in new skin
  formation
• Clotting, scabbing, new cells, scars
• Sometimes outside agents are needed
• Medicines, creams, etc.
• Skin grafts

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And now for your viewing pleasure!