Skin structure, functions & dermatomes

*Read from lecture notes

Important key points

• Epidermis (ectoderm)
  • Stratum corneum
  • S. lucidum
    • only in thick skin (sole, palms)
  • S. granulosum
    • 1st layer that has nuclei
    • cuts off nutrition to cells above
  • S. spinosum
    • thickest layer
    • together with S. basale = Malpighian layer
  • S. basale
    • cell renewal
• Dermis (mesoderm)
  • Papillary layer
    • Collagen type 3
    • Meissners’s corpuscles: touch
    • Krauses’s end bulb: cold
    • Free nerve endings: pain
  • Reticular layer
    • Collagen type 1
    • Muscle cells
    • Pacinian corpuscles: pressure
    • Ruffini end organ: heat
• Hypodermis
  • Loose connective tissue
  • Fat

Langerhan’s : Immune

Merkel: Mechanoreceptors (touch, fingers)

Sweat

• Eccrine
  • cholinergic innervation
  • watery secretion
  • thermoregulatory
• Apocrine
  • sympathetic control
  • viscous secretion

Langer’s line: crease line, minimal scar

Dermatomes

• C6: thumb
• T4: nipple
• T10: umbilicus
• L5: dorsum of foot
• S1: sole of foot
• S2-S4: perineum