Skin Functions and Structure

Skin - The Jack of All Trades

• Skin is the largest organ, making up 15% of an adult's body weight.
• It's the outermost layer, forming a protective barrier.

Functions of Skin

• Protection:

  • Shields underlying tissues from impacts.
  • Prevents water loss through evaporation.
  • Blocks harmful substances and germs.
  • Protects against excessive UV light.

• Sensation:

  • Detects touch, pain, pressure, and temperature.

• Temperature Regulation:

  • Prevents heat loss in cold environments.
  • Facilitates heat loss in warm environments.

• Storage:

  • Stores fat in specialized cells.

• Excretion:

  • Eliminates water, salts, and urea through sweat.

• Synthesis:

  • (Not further detailed in provided text)

• Grip:

  • Ridges and grooves on palms and fingers enhance grip.

Structure of Skin (Epidermis)

• Cornified Layer (Stratum Corneum):

  • Outermost layer of flattened, dead cells.
  • Made of keratin.
  • Protects against damage, infection, and water loss.

• Granular Layer (Stratum Granulosum):

  • Middle layer.
  • Contains cells that produce keratin.

• Malpighian Layer (Stratum Malpighi or Germinative Layer):

  • Innermost layer.
  • Active cell division produces new skin cells.
  • Contains melanin which determines skin color.

Skin Structure (Dermis)

• Dermis:
  • Thick layer of connective tissue.
  • Contains nerve fibers, blood vessels, sensory receptors, hair follicles, and sweat glands.
  • Contains elastic fibers for flexibility.
• Subcutaneous Layer:
  • Layer below the dermis containing fat.
  • Provides insulation, shock absorption, and energy storage.

Abnormal Skin Conditions

• Leucoderma/Vitiligo:

  • Loss of skin pigmentation in patches.
  • Cause unknown.

• Albinism:

  • Complete loss of pigmentation.
  • Genetic trait.