The Organisation of Cells

• Specialised cells


  Cells that are adapted for specific functions in multicellular organisms
• Specialised cells


  • Epithelial cells in the small intestine
  • Red blood cells
• Tissue


  A group of cells that work together to perform a particular function
• Tissues


  • Epithelial tissue
  • Muscle tissue
• Organ


  Different tissues working together
• Organs


  • Heart
• Organ system


  Different organs working together
• Xylem vessel cells


  • Lose top and bottom walls to form continuous tubes for water transport
  • Cell contents broken down, walls thickened with lignin for support
• Phloem vessel cells


  Tubular cells that transport dissolved sugars and amino acids, retain some subcellular structures and are living
• Muscle cells


  • Contain layers of protein filaments that can slide over each other to cause contraction
  • High density of mitochondria to provide energy
  • Skeletal muscle cells fuse together during development
• Ciliated epithelial cells


  • Have cilia that beat in a coordinated way to move substances across the surface
  • Goblet cells secrete mucus to trap dust, dirt and microorganisms
• Squamous epithelial cells


  • Form a single flattened layer that reduces diffusion distance and is permeable
• Cartilage


  Strong and flexible tissue that provides support, found in rings along the trachea
• Specialised cells organised into tissues, tissues into organs, and organs into organ systems

  • Epithelial cells into epithelial tissue, into stomach organ, into digestive system organ system
  • Muscle cells into muscle tissue, into bladder organ, into urinary system organ system
  • Neurones into neural tissue, into brain organ, into central nervous system organ system
  • Rod and cone cells into retina tissue, into eye organ, into visual system organ system