Dermatology Nail PR1

• Fingernails and toenails


  Made up of heavily keratinized epidermal cells
• Keratinized cells


  Cells that were once alive but filled with the keratin protein as they matured, causing them to lose their organelles and dye
• Parts of a nail (from top view)


  • Free edge
  • Nail body
  • Lunula
  • Cuticle or eponychium
  • Nail root
• Parts of a nail (from side view)


  • Free edge
  • Nail body
  • Lunula
  • Cuticle
  • Nail root
• Nail bed


  Located under the nail body, composed of living cell layers
• Nail matrix


  The growing part of the nail, located toward the palm of the hand where the nail bed thickens
• Nail growth


  Mitosis, or cell division, from beneath the lunula and the root
• Hyponychium


  Thickened part of the skin where the free edge of the nail hangs over
• Fingernails grow about three millimeters per month
• Toenails grow about one millimeter per month
• It takes about six months for a fingernail to grow from the root to the free edge
• It takes twelve to eighteen months for a toenail to grow from the root to the free edge
• Nails grow slightly faster in the summer


  Caused by more exposure to the sun and increased circulation from being more active
• Functions of nails


  • Prevent damage to bones and underlying soft tissue
  • Help with digging, climbing, and scratching
  • Help with grasping things (fingernails)
• Hair structure consists of: 1. medulla (most inner layer) 2. cortex 3. cuticle (outer layer) and moreover, it also has additional layers when it goes into dermis becoming Hair follicle/bulb: 4. Inner root sheath 5. Outer root sheath 6. Hair matrix 7. Hair papilla(blood vessel)