Principles of organisation

• The bodies of large multicellular organisms are organised into different organ systems.
• Cell -> Tissue -> Organ -> Organ system
• Cells are the basic building blocks of all living organisms
• Examples of cells are muscle cells and secretory cells.
• Tissues are group of cells with similar structure and function. Some examples are muscular tissue , glandular tissue and epithelial tissue.
• Organs are combinations of tissues each with a specific function. Some examples are the heart , stomach , lungs and kidneys.
• Organ systems are two or more organs working together for example digestive system , circulatory system and the respiratory system.