INTEGUMENTARY SYSTEM

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INTEGUMENTARYSYSTEM
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• Integument skin
• Appendages hair, nails, glands
• The skin is the largest organ of the body

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Functions

• Protection
• Regulation
• Absorption
• Synthesis
• Sensory

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Protection

• Covers and protects the entire body from
  microorganisms
• Protects from UV rays melanin (pigment in the
  skin)
• Keratin a protein in the outermost layer of the
  skin waterproofs and toughens skin and
  protects from excessive water loss, resists
  harmful chemicals, and protects against physical
  tears

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Regulation

• Maintains normal body temperature by regulating
  sweat secretion and regulating the flow of blood
  close to the body surface.
• Evaporation of sweat from the body surface
• Radiation of heat at the body surface due to the
  dilation of blood vessels close to the skin

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• Excessive heat loss causes shivering (contraction
  of skeletal muscle) increasing heat production
  and goosebumps (contraction of arrector pili
  muscle) pulling hair shaft vertical, creating an
  insulated air space over the skin.

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Absorption

• Absorbs oxygen and carbon dioxide and UV rays
• Steroids (hydrocortisone) and fat-soluble
  vitamins (ie D) are readily absorbed
• Topical medications motion sickness patch etc
• Toxins and pesticides

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Synthesis

• Skin produces melanin, keratin, vitamin D
• Melanin protects the skin from UV rays
  determines skin color
• Keratin helps waterproof the skin and protects
  from abrasions and bacteria
• Vitamin D stimulated by UV light. Enters blood
  and helps develop strong healthy bones. Vitamin
  D deficiency causes Rickets

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Sensory

• Sensory nerve endings tell about environment
• They respond to heat, cold, pressure, touch,
  vibration, pain

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The skin is a membrane

• Membrane thin sheetlike structure has many
  varying important functions in the body.
• Membranes
• 1. Cover and protect
• 2. Serve as anchors
• 3. Secrete lubricating fluids

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2 Types of membranes

• Epithelial
• Connective

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Epithelial

• Cutaneous membranes skin
• Serous membranes lines body cavities and covers
  the surface of organs secretes watery fluid that
  helps reduce friction parietal vs. visceral
  pleura vs. peritoneum
• Mucous membranes line the respiratory,
  digestive, urinary, and reproductive tracts
  secrete mucus

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Connective

• Synovial membranes
• - line spaces between joints that move
• - secrete synovial fluid thick, colorless
• - line bursae (sacs that cushion joints)

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Types of body membranes
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Layers of skin

• Epidermis
• - outermost layer
• - layers of epithelial cells
• - cells are formed in deeper layers of epidermis
  and move toward the surface
• - outermost layer of epidermis dead cells
  continuously flake off

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Epidermis contd

• Keratin found in outermost layers of epidermis
• Melanin produced in deepest layers of epidermis
• Increased oxygen and blood flow to the skin
  causes a pink flush to appear
• Low blood oxygen levels and decrease blood flow
  causes cyanosis (bluish gray color)

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Layers of skin contd

• Dermis
• - deepest layer and thicker
• - loose connective tissue collagen fibers
  (toughness) and elastic fibers (elasticity)
• - dermal papillae fingerprints bind the
  epidermis to the dermis
• - contains nerves, muscles, hair follicles,
  glands, blood vessels, sensory organs

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Layers of skin contd

• Subcutaneous Tissue (hypodermis)
• - contains adipose tissue (fat) and loose
  connective tissue
• - fat insulates the body from heat and cold,
  stored energy, shock absorber, and protects
  underlying tissues

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Microscopic view of skin
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Appendages of the skin

• Hair
• - follicles are specialized structures required
  for hair growth
• - hair papilla cells at the base of follicles
  where hair growth begins
• - arrector pili muscle attached to the base of
  the papilla that contract when frightened or cold
• - sebaceous glands secrete sebum (oily)

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Hair follicle
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Appendages contd

• Receptors
• - sensory touch, pain, temp., pressure
• Nails
• - nail body visible part
• - root lies beneath skin
• - cuticle fold of skin hiding root
• - lunula nail body nearest the root white
  crescent shaped area

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Structure of Nails
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Structure of Nails
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Appendages contd

• Skin glands
• - sweat glands
• 1) eccrine numerous and widespread
• transport sweat
• 2) apocrine axilla and genital areas
• thicker secretions
• odor

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Appendages contd

• 4. Skin glands contd
• - sebaceous glands secrete oil (sebum)
• for hair and skin

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Skin injuries/conditions

• Burns
• - severity depends on total area depth
• - rule of nines
• - 1st, 2nd, 3rd degree

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2nd degree burn
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3rd degree burn
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Blisters

• Caused by burns, irritants, friction
• Usually occur between layers of epidermis and
  dermis

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Contusions - bruise

• Bleeding under the skin
• Ecchymosis - discoloration

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Subungual hematoma

• Pooling of blood under the nail

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Ingrown toenail
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Calluses

• Thickening of skin over pressure points

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Wounds

• 1. Abrasion (scrape)

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Wounds

• 2. Laceration (cut) sutures
• Avulsion (torn off)
• Puncture easily infected

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Wound healing

• Degree of injury
• Location blood supply
• Nutrition
• Illness
• Medications
• Infection
• Proximity of damaged tissue
• Stress placed on area