T3.1 organ systems

• Tissue


  Groups of associated cells that work together to perform a related function
• Tissue


  • Function determined by structure of cells
• Histology


  Study of tissues and how they are arranged into organs
• Four types of tissues

  • Epithelial tissue
  • Connective tissue
  • Muscle tissue
  • Nerve tissue
• Epithelial tissue


  • Closely packed cells with generally little intercellular space
  • Cells sit on basement membrane with their basal surface
  • Apical surface faces outside/body cavity; may contain cilia and microvilli
  • Avascular but have good nerve supply
  • Show rapid cell division
• Classification of epithelial tissue based on arrangement of cells in layers

  • Simple epithelium - single layer
  • Stratified epithelium - two or more layers
  • Pseudostratified epithelium - single layer but it appears stratified
• Classification of epithelial tissue based on cell shapes

  • Squamous (thin, flat with single nucleus)
  • Cuboidal (cells as tall as they are wide with single, centrally located nucleus)
  • Columnar (cells taller than they are wide)
  • Transitional (can change shape)
• Form = function


  Epithelial tissue that covers and lines
• Epithelial tissue that covers and lines

  • Epidermis of skin
  • Lining of blood vessels and ducts
  • Lining of respiratory, reproductive, urinary and gastrointestinal tracts
• Glandular epithelium


  Forms secreting proportion of glands
• Four types of body membranes

  • Mucous membrane
  • Serous membrane
  • Cutaneous membrane
  • Synovial membrane
• Connective tissue


  Comprised of cells, gels (ground substances) and fibres
• Cells that comprise connective tissue

  • Fibroblasts
  • Chondroblasts and chondrocytes
  • Adipocytes
  • Osteoblasts and osteocytes
• Gels (ground substance)


  Holds cells and fibres together, mainly made up of sugar and proteins
• Fibres that determine strength and/or stretchability of connective tissue

  • Collagen fibres
  • Elastic fibres
  • Reticular fibres
• Muscle tissue


  Comprised of elongated cells that are specialised to contract in response to stimulation
• Nervous tissue


  Comprised of specialised cells (called neurons) that allow for fast and direct communication around the body
• Neurons


  • Highly branched cells composed of body, dendrites (multiple short processes) and axon (single long processes)
  • Receive, send and process nerve impulses
• Glial cells


  Help nourish, support and protect neurons
• Integumentary system


  Skin composed of two layers: epidermis (outermost proportion) and dermis (deeper layering underlying the epidermis)
• Integumentary system


  • Provides first line of defence, sensory information, prevents fluid loss, helps generate and release heat (via sweating and vasodilation), works with other systems for excretion of waste products