The Basic Facts

Human Skin - The Basic Facts

human skin cross-section diagram


  • what is skin? (Latin - cutis)
    • is your body's largest organ
    • covers your entire body
    • has a total surface area of about 1.5 - 2 m2 (depending on your body's size)
    • makes up about 7% of your body's total weight
    • weighs about 4 kg
    • suffers the most wear and abuse of any part of the human body

  • composition of your skin:
    • two (2) distinct main layers: the EPIDERMIS and the DERMIS
      • nature of:
        • the thinner of the two main skin layers
        • made up of many cell layers
        • has no blood vessels of its own
        • the most inner cell layer provides cells for the outer cell layers, by having its cube-shaped cells divide quickly
        • new cells push older cells toward the surface
        • as epidermal cells move toward the surface, they become enriched in keratin (a fiberous protein - also found in hair and nails)
        • upon reaching the surface, these cells have died and become flat
        • at the surface, these dead cells "slough-off"
        • Epidermis is replaced every few weeks
        • in a lifetime the average person will shed about 18 kg of skin
      • structure of (from surface inward):
        • Stratum Corneum (outer most layer) - horny layer - accounts for up to 75% of the Epidermis' thickness
        • Granular layer (stratum granulosum)
        • Spinous layer (stratum spinosum)
        • Basal layer
    • DERMIS:
      • nature of:
        • the thicker of the two main skin layers
        • is protected by the Epidermis
        • made up of connective tissue - with elastin fibers (to keep it flexible and pliable) and collagen fibers (for strength and resilience)
        • rich in blood vessels and nerve endings
        • feeds the Epidermis with nutrients and oxygen
        • contains the structures of the intergumentary system (hair follicles, oil and sweat glands)

this informational service is brought to you by Nancy K. Brown Aesthetics, Inc.