a. Organisation

• Organelle → Cell → Tissue → Organ → Organ System
• Organelles


  Also known as subcellular structures, the parts that make up a cell, including the nucleus, ribosomes, and mitochondria
• Cells come in all sorts of shapes and sizes and contain different combinations and numbers of the organelles
• Specialized cells

  • Epithelial cells
  • Muscle cells
  • Different types of glandular cells
• Tissues


  A group of similar cells that work together to carry out a particular function
• Tissues

  • Epithelial tissue
  • Muscle tissue
  • Glandular tissue
• Organ


  A group of different tissues that work together to perform a particular function
• Organ system


  A group of organs that work together to perform a particular function
• Organism


  The highest level with multiple organ systems working together to form the organism