Integumentary System

• The integumentary system is the largest organ system, consisting of skin, hair, nails, glands, and sensory receptors.
• What epithelial membranes are in the integumentary system? (2)

  • Cutaneous
  • mucous
  • serous
• What/where are serous membranes?

  lines the body cavities
• What is the function of serous membranes?

  Secretes slimy fluid to help reduce friction and allow organs to slide freely over one another
• What are serous membranes made up of?

  • superficial layer of simple squamous epithelium
  • deeper layer of loose connective tissue
• Where are mucous membranes?

  line the tubular structures that open to the outside of the body
• What are mucous membranes made of?

  • layer of epithelium
  • layer of loose connective tissue
• What is an example of the cutaneous membrane? 


  Skin
• What is the function of the skin?

  • protects body against infections
  • Regulates temperature
  • maintains a balance of fluids
  • synthesizes vitamin D
  • contains sensory functions
• What are the three layers the skin is made of?

  1. Epidermis (superficial layer)
  2. Dermis
  3. subcutaneous layer (deepest layer)
• What is the epidermis made of?

  stratified squamous epithelium tissue arranged is layers called strata
• What is the dermis made of?

  -loose connective tissue

  -fibroblasts

  -white blood cells

  -accessory structures
• What is the subcutaneous layer of the skin made of?

  • loose connective tissue
  • adipose tissue
  • blood vessels
  • nerves
• What are the layers of the epidermis?

  1. Stratum corneum
  2. stratum lucidum
  3. stratum granulosum
  4. stratum spinosum
  5. stratum basale
• What is the most superficial layer in the epidermis?

  Stratum cornuem
• What is the hypodermis made of?

  • adipose connective tissue
  • blood vessels
  • nerve fibers
• What do keratinocyes do?

  secrete keratin which hardens and waterproofs cells
• What do melanocytes do?

  secretes melanin which provides skin pigment
• What does the stratum corneum contain?

  cells that have been hardened by keratin
• Where can the stratum lucidum be found on the body?

  • palms of hands
  • soles of feet
• what does the stratum granulosum contain?

  • Cells that lost their nuclei, but remain active and secrete ketain
  • cells contain granules in the cytoplams that have keratin
• What does the stratum spinosum contain?

  prickle cells
• what do prickle cells do?

  small radiating processes that connect with other cells
• What is synthesized in the spinosum?

  Keratin
• What does the stratum basale contain?

  epidermal stem cells

  melanocytes
• What is the deepest layer of the epidermis?

  stratum basale
• Vitamin D synthesis

  1. 7-dehydrocholesterol absorbs ultraviolet radiation

  2. Molecule travels to liver

  3. Molecule converted to active form of vitamin D (1,25 hydroxycholecalciferol) in kidney
• Vitamin D


  Also known as cholecalciferol
• Vitamin D

  • Helps the body absorb calcium
  • Works to help in calcium transport in the intestines
• The skin helps to synthesize vitamin D
• Psoriasis

  An abnormality of keratinocytes
• Keratinocytes in psoriasis

  1. Abnormally divide rapidly

  2. Migrate from stratum basale to the stratum corneum

  3. Many immature cells reach the stratum corneum

  4. Producing flaky, silvery scales (mostly on knees, elbows and scalp)
• Epidermis

  Responds to the environment
• Friction

  • Causes the formation of corns and calluses
• Melanocyte


  A cell found in the epidermis that produces the pigment melanin that gives skin its color
• Melanocytes

  • Located in the deepest portion of the epidermis and superficial dermis
• The color of the skin results from the activity of the melanocytes, not the number
• Melanocytes respond to ultraviolet radiation

  1. Produce more melanin pigment

  2. Turns skin a darker color
• UVB radiation

  Wavelength of approximately 320 nm
• The hair and middle layer of the eye contain melanocytes