Skin structure and function

• Skin tissue types


  • Epidermis
  • Dermis
  • Hypodermis
• Epidermis


  • Keratinised stratified squamous epithelium
  • Avascular (lacks blood vessels, receives nutrients via diffusion)
  • Stratified (multiple cell layers for protection)
• Epidermis structure


  1. Stratum basale (basal layer)

  2. Stratum spinosum (spiny layer)

  3. Stratum granulosum (granular layer)

  4. Stratum lucidum (clear layer)

  5. Stratum corneum (horny layer)
• Keratinocytes


  Primary cell type in epidermis, produces keratin for strength and waterproofing
• Melanocytes


  Cells that produce melanin, responsible for skin colour and UV protection
• Langerhans cells


  Immune cells that help fight pathogens
• Merkel cells


  Sensory cells associated with touch reception
• Epidermis structure and function

  Protection, waterproofing, UV protection, immune defense, sensation
• Dermis


  • Mix of loose areolar and dense irregular connective tissue
  • Vascularized (contains blood vessels)
  • Innervated (rich in nerve endings)
• Dermis structure


  1. Papillary layer

  2. Reticular layer
• Fibroblasts


  Primary cells in dermis that produce collagen, elastin and extracellular matrix
• Macrophages


  Immune cells involved in defense and repair
• Mast cells


  Cells important in inflammation and allergic responses
• Dermis structure and function

  Structural support, nourishment and waste removal, sensation, thermoregulation, immune defense, hair and gland function
• Hypodermis


  • Mix of areolar and adipose connective tissue
  • Contains larger blood vessels and nerves compared to dermis
  • Thickness varies widely depending on body location
• Adipocytes


  Primary cells in hypodermis, specialized for storing fat
• Hypodermis structure and function

  Energy storage, insulation, cushioning and protection, anchoring the skin, blood supply and thermoregulation, hormone production and metabolism