Integumentary System

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Integumentary System

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Integumentary System

• Consists of two components
• Skin
• Skin Derivatives (accessory structures) sweat
  and oil glands hair nails

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Functions
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Integumentary System

• Skin has two layers a subcutaneous layer
• a. Epidermis
• b. Dermis
• c. Hypodermis

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Epidermis
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Dermis
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Dermal Layers

• 1. Papillary layer- loosely woven mat of fibers,
  rich blood supply, dermal papillae (fingerprints)
• 2. Reticular layer- dense irregular CT, dense
  bundles of collagen fibers, cleavage lines

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Subcutaneous Layer
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Skin Color

• Melanin- made from tyrosine, yellow ?
  reddish-brown?black, color differences due to
  type amount of melanin produced
• freckles moles local accumulation of melanin,
• protects DNA from UV photodamage, albino-
  individuals without tyrosinase

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Skin Color

• 2. Carotene- yellow to orange pigment, found in
  carrots etc, accumulates in fat and stratum
  corneum (palms and soles), seen when diet rich in
  carotene
• 3. Hemoglobin- RBCs in dermal capillaries shown
  in light skin

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Appendages of the Skin

• 1. Hair
• 2. Nails
• 3. Sudoriferous or sweat glands
• 4. Sebaceous (oil) glands

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Arrector Pili Hair Root Plexus

• Arrector pili- bundle of smooth muscle associated
  with each hair follicle, hair raising goose
  bumps
• Hair root plexus sensory nerve endings
  sensitive to touch

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So... do you know...
what causes goose bumps?
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Hair Functions

• Warms
• Senses-
• Protects- on head from trauma, sun
• 4. Shields- eyelashes
• 5. Filters- nose hair

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Nails

• Scale-like modification of epidermis hard,
  keratinized cells that form a clear protective
  covering
• 2. Act as tools, to help pick up objects

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(merocrine)
Modified sweat glands
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Functions of Skin

• 1. Protection
• 2. Temperature regulation
• 3. Cutaneous sensation
• 4. Metabolic Functions Excretion

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Cutaneous Sensation

• 1. Meissners corpuscles- light touch receptors,
  just below epidermis
• 2. Pacinian receptors- mechanoreceptors, deep
  pressure touch receptors deep in the dermis
• 3. Root hair plexi
• 4. Bare nerve endings- pain receptors

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Metabolic Functions

• 1. Break down carcinogens that penetrate skin
• 2. Collagenase- aids in turnover of collagen and
  helps prevent wrinkles

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Excretion

• 1. Limited nitrogen wastes in sweat

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Life-span changes

• Skin repair processes take longer due to reduced
  number and activity of stem cells.
• Skin forms wrinkles and becomes less resilient.
• Skins immune responsiveness is diminished.
• Skin becomes drier due to decreased sebaceous
  gland activity.
• Sweat production diminishes.
• Blood supply to the dermis is reduced --gt
  impaired thermoregulation.
• Hair thinning and loss.
• Development of skin cancers

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All this info is making ...
my epithelium crawl !