The integumentary system is a dynamic continuous body covering composed of:

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Chapter 4
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Overview

• The integumentary system is a dynamic continuous
  body covering composed of
• Blood vessels
• Connective tissue structures
• Glands
• Hair
• Nails
• Skin

Chapter 4 The Skin and Its Parts
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The Integumentary System
The skin has three distinct layers the
epidermis, the dermis, and the hypodermis (or
subcutaneous layer).
Chapter 4 The Skin and Its Parts
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The Integumentary System
Epidermis Outermost layer, where new skin cells
are continually produced
Chapter 4 The Skin and Its Parts
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The Integumentary System
Dermis Middle layer composed mostly of
connective tissue
Chapter 4 The Skin and Its Parts
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The Integumentary System
Hypodermis (also called the subcutaneous
layer) Innermost layer, composed of loosely
arranged elastic fibers that anchor the skin to
underlying tissue
Chapter 4 The Skin and Its Parts
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The Integumentary System

• The four main functions of the integumentary
  system are
• Protection against environmental damage
• Heat regulation maintain a constant internal
  temperature
• Sensation receiving stimuli from the
  environment
• Waste excretion

Chapter 4 The Skin and Its Parts
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GLANDS

• 3 types of glands commonly found in the skin
• Ceruminous glands
• Produces a waxy secretion called cerumen
• Found in the lining of the ear canal
• Sebaceous glands
• Produce an oily secretion called sebum
• Secreted into hair follicles moves to the
  surface of the skin
• Sweat glands

Chapter 4 The Skin and Its Parts
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SWEAT GLANDS

• 2 Types
• Apocrine sweat glands
• Secrete odorous sweat into the hair follicles of
  the armpits, navel, and groin regions
• Inactive until puberty
• Usually tapers off in the elderly

Chapter 4 The Skin and Its Parts
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SWEAT GLANDS

• Apocrine sweat glands contain chemicals called
  pheromones, which are believed to play a role in
  courtship and social behavior
• ex.) dogs sniffing people
• Why does your sweat smell so bad?
• The secretions are easily broken down by
  bacteria, which creates body odors.

Chapter 4 The Skin and Its Parts
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SWEAT GLANDS

• Eccrine Sweat Glands
• Found mostly on the skin of armpits, forehead,
  palms, and soles
• Eccrine sweat gland activity is genetically
  determined
• Human eccrine sweat is composed primarily of
  water with various concentrations of salts,
  organic compounds, and wastes, including urea.

Chapter 4 The Skin and Its Parts
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Interesting Fact
Antiperspirants can be used to reduce the amount
of sweat (from both gland types), thereby
reducing odors and dampness. How do
antiperspirants work? There is an electrical
repulsion between a negatively charged ingredient
and the negatively charged sweat molecules.
Chapter 4 The Skin and Its Parts
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NAILS

• Fingernails toenails are nothing more than a
  keratin secretion.
• Keratinocytes at the base of the nail root
  gradually move up to the surface of the skin.
• The cells closest to the surface die, flatten,
  press tightly together, disintegrate to form
  the nail body.
• Fingernails of a healthy person typically grow
  1/8th an inch per month (slightly faster than
  toenails)

Chapter 4 The Skin and Its Parts
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Wellness and Illness over the Life Span

• Aging is due to
• Intrinsic factors
• aging caused by the natural decline of cells
• OR
• Extrinsic factors
• aging caused by environmental factors (disease,
  pollution, sun exposure)
• Ones lifestyle can accelerate aging.

Chapter 4 The Skin and Its Parts
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Wellness and Illness over the Life Span

• Pathology can be categorized as
• Degenerative
• refers to diseases that progressively
• deteriorate tissues
• examples include skin cancer, moles,skin tags
• Genetic
• includes acne, psoriasis, spider veins
• Infectious
• diseases including impetigo, ringworm, warts

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DISORDERS HOMEOSTATIC IMBALANCES

• Skin cancer can be caused by excessive exposure
  to sunlight.
• Risk factors for skin cancer include skin type,
  sun exposure, family history, age, and
  immunological status.

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Skin disorders

• Basal cell carcinoma
• 30 of Caucasians get this type of skin
• cancer. Does not metastasize.
• Squamous Cell carcinoma arises from the
  keratinocytes in the stratum spinosum. May
  metastasize (spread to other body parts).
• Melanoma arises in the melanocytes. Rapidly
  metastasizes.

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Melanocytes

• Produces melanin for protection from UV
  radiation.
• Responsible for skin color.
• Melanoma.

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Melanoma
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ABCD Rule
Asymmetry, Border irregularity, Color, Diameter
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Burns

• Denaturation of cell proteins.
• Dehydration, protein loss, and infection.
• First degree burns only the epidermis (sunburn).
• Second degree burns epidermis and upper dermis.
  May include fluid-filled blisters that separate
  epidermis dermis. Heals without grafting in 3
  to 4 weeks may scar

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• Third degree burns full thickness burns
• destroy epidermis, dermis epidermal
  derivatives
• damaged area is numb (not painful at all) due
  to loss of sensory nerves
• -- Skin grafting is almost always necessary.

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Types of Burns
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Tattoos

• Tattooing is a permanent coloration of the skin
  in which a foreign pigment is injected into the
  dermis.

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Possible Dangers of Body Tattoos

• Infection, allergic reaction to the ink,
  psoriasis, and dermatitis
• Diseases such as HIV, AIDS, Hepatitis B and C,
  and even syphilis
• Body tattoos can also cause tumors