ANA1 L4 Integumentary

• What is another name for the skin?

  Integument
• What is the primary function of the skin?


  To provide a tough, protective covering for the body
• With which body structures is the skin continuous?

  Mucosa of the mouth, nose, anal canal, genital openings, and eyes
• What are the functions of the skin?

  1. Prevent entry of pathogens and loss of body fluids
  2. Excrete waste
  3. Regulate body temperature
  4. Sense organ
  5. Immune function
  6. Production of vitamin D
• What are the two layers of the skin?

  Epidermis and dermis
• What type of epithelium is the epidermis made of?


  Keratinized stratified squamous epithelium
• How thick is the epidermis?


  0.1 mm
• What type of connective tissue is the dermis made of?


  Dense irregular connective tissue
• How thick is the dermis?


  0.6 – 4 mm
• What is the subcutaneous tissue also known as?


  • Hypodermis
  • Superficial fascia
  • Loose connective tissue
  • Not part of the skin
  • Allows skin to slide over underlying tissue
• What are the layers of the epidermis?


  1. Corneum – horny
  2. Lucidum – clear
  3. Granulosum – granular
  4. Spinosum – thornlike
  5. Basale – germinative
• What is the function of the basal layer of the epidermis?


  It includes stem cells and produces keratinocytes
• How many rows of keratinocytes are in the spinosum layer?


  1. 10 rows
• What do the granules in the granulosum layer contain?


  Keratohyalin and lamellar granules
• Where is the lucidum layer found?


  In the palms and soles
• What is the function of the corneum layer?


  It consists of dead, flat keratinocytes that protect the underlying layers
• What are the dermal layers?


  1. Papillary – nipple-like
  2. Reticular – net
• What is the function of the papillary layer?


  It contains dermal ridges that house capillaries and sensory receptors
• What is the thickness of the papillary layer?


  1/5 of the dermis
• What is the function of the reticular layer?


  It provides toughness and strength to the skin
• What are the two types of skin?

  Thin skin and thick skin
• What is the thickness range of thin skin?

  0.10-0.15 mm
• What features are absent in thin skin?

  Stratum lucidum and epidermal ridges
• What features are present in thick skin?

  Stratum lucidum and numerous sweat glands
• What are the types of cells in the skin?

  1. Keratinocytes
  2. Melanocytes
  3. Langerhans cells
  4. Merkel cells
• What is the function of keratinocytes?


  To produce keratin and lamellar granules
• What is the role of melanocytes?


  To secrete melanin that contributes to skin color
• Where are Langerhans cells located?


  In the stratum spinosum
• What is the function of Merkel cells?


  To act as touch receptors
• What are the types of sensory nerve endings in the skin?


  1. Simple

  • Free nerve ending (pain receptor)
  • Hair follicle nerve ending (hair motion receptor)

  1. Expanded-tip

  • Merkel disc (touch receptor)

  1. Encapsulated

  • Krause endbulbs (touch receptor)
  • Meissner corpuscles (touch receptor)
  • Ruffini corpuscles (stretch)
  • Pacinian corpuscles (pressure and vibration)
• What pigments give skin color?

  1. Melanin – brown to black shade
  2. Carotene – yellowish
  3. Hemoglobin – red
• What are the appendages of the skin?


  1. Hair

  • Vellus hair (short, fine, pale)
  • Terminal hair (long, coarse, pigmented)

  1. Nail
  2. Sweat glands

  • Eccrine
  • Apocrine

  1. Sebaceous glands
• What is the structure of hair?

  It consists of three layers: medulla, cortex, and cuticle
• What is the function of the arrector pili muscle?


  It causes hair to stand on end and produces goosebumps
• What are the components of nails?

  • Nail body (visible portion)
  • Free edge (extends past distal end)
  • Nail root (buried in skin fold)
  • Nail matrix
  • Lunula (small part of matrix)
  • Nail bed (secures nail to fingertip)
  • Cuticle (stratum corneum extending to nail body)
• What is the function of eccrine sweat glands?


  To regulate temperature and respond to emotional stress
• Where are eccrine sweat glands located?


  Throughout the skin, especially on the forehead, palms, and soles
• What is the function of apocrine sweat glands?


  To respond to emotional stress and sexual excitement
• Where are apocrine sweat glands located?


  In the axilla, groin, areola, clitoris, labia minora, and beard
• What is the function of sebaceous glands?


  To prevent water loss and inhibit bacterial growth