INTEGUMENTARY SYSTEM

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INTEGUMENTARY SYSTEM
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Terms to remember

• Tissue
• Organ
• Organ system
• Dermatology branch of science specializing in
  diagnosing and treating skin disorders.

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Integumentary System

• Skin accessory structures (hair, nails, glands,
  some receptors)
• System most widely exposed to trauma, infection,
  disease
• Skin is the largest organ in surface area and
  weight
• Adult skin 2 square meters (22sq.ft.)

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Components of Integumentary System

• Skin layers
• Epidermis (outer)
• Dermis (middle)
• Subcutaneous layer a/k/a hypodermis (inner)

• Accessory structures located in the dermis
• Nails
• Glands
• Pili (hair)
• Sense receptors

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Functions of the Skin

• Protection-of underlying tissues and organs
• Excretion-of salts, water and organic wastes
• Maintenance of normal body temperature
• Synthesis of Vitamin D
• Storage of nutrients
• Sensory function-detection of touch, pressure,
  pain and temperature.

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EPIDERMIS

• Outer layer
• Made of stratified squamous epithelium
• keratinocytes cells containing keratin (protein
  for waterproofing)
• Melanocytes cells containing melanin (pigment)
• Thick skin has 5 layers and thin skin has only 4

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EPIDERMAL LAYERS (STRATA)

• Stratum Germinativum (Basale)
• Single, bottom mitotic layer
• Stratum Spinosum
• 8-10 cell layers
• Stratum Granulosum
• 5 cell layers release lipids
• Stratum Lucidum
• 5 cell layers only present in thick skin
• Stratum Corneum
• 30 cell layers, dead calluses form here

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Skin Pigmentation

• Carotene, a yellow-orange pigment
• Melanin, a brown-black pigment protects against
  UV damage
• Hemoglobin, a red pigment
• These pigments are also responsible for the
  variety of hair colors.

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Pigment Conditions

• Albinism inherited disorder, where the
  individual is unable to produce melanin.
• Vitiligo irregular white spots due to lack of
  melanin.
• Freckles irregular dark spots due to
  concentrated areas of melanin
• Nevus birthmark or mole
• Cyanosis bluing of skin or nails due to hypoxia
  or anoxia
• Jaundice yellowing of skin or eyes due to
  build-up of bilirubin in blood
• Erythema reddening of the skin due to engorged
  capillaries (exercise, heat, infection)

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Albinism Vitiligo
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Nevus Cyanosis
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Jaundice Erythema
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DERMIS

• Below epidermis
• contains collagen and elastin fibers in outer
  regions
• Contains connective tissue, adipose tissue and
  sensory receptors in inner layer
• Surface area is increased by dermal papillae
  (which give us fingerprints)

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SUBCUTANEOUS / HYPODERMIS

• Also called the subQ layer
• Found below dermis
• Contains connective tissue, such as adipose and
  areolar

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Hair

• a/k/a pili
• Hair functions-protection from UV light, cushion
  a blow and insulate the head, prevent entry of
  foreign materials.
• Anatomy of hair (see p. 123)
• Shaft, root, follicle, bulb, matrix, papilla
• Normal hair loss 100 hairs/day
• Arrector pili muscles goosebumps

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Hair structure
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Glands

• Sebaceous Glands (oil)-secrete sebum. Provides
  lubrication and inhibits growth of bacteria.
• Sudoriferous Glands (sweat)- secrete
  perspiration. Functions to regulate body
  temperature and excrete waste.
• Apocrine concentrated in axilla genital
  regions
• Eccrine widely distributed on body
• Mammary Glands (milk)- modified sweat glands
• Ceruminous Glands (wax) secrete cerumen
  modified oil glands

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Glands
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Nails

• Tightly compressed cells packed with keratin.
• Know the parts (see p. 122)
• Free edge
• Nail body
• Lunula
• Cuticle
• Nail root
• Nail bed

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Nail structures
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Receptors

• Thermoreceptors temperature
• Meissners corpuscle fine touch vibration
• Pacinian corpuscle pressure
• Ruffinis corpuscle stretching
• Nociceptors itch, tickle, and pain
• Hair root plexus sensations on skin

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Receptor location
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Skin Damage

• Burns
• Caused by UV light, chemicals, abrasion
• 3 types
• 1st degree epidermis affected reddening of
  skin, but no blistering
• 2nd degree dermis affected blisters present and
  can be painful
• 3rd degree various layers of SubQ and lower are
  affected usually not painful require grafting
  dehydration probable

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1st degree burns
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2nd degree burns
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3rd degree burns
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REVIEW

• Skin Cross-Section
• Another Cross-Section
• Yet Another Cross-Section
• Burn Review