Organization of the Body


The cell is the basic functional unit of all known living organisms. The cell is the smallest unit of life that can replicate independently.

Cells group to form tissues. Tissues have a specialized functions. Examples of tissues include blood, muscle and bone.

Different tissues group to form organs. Examples of organs include stomach, liver, heart and brain.

Organs form organ systems which perform a particular function which maintains homeostasis and maintains normal health.

The digestive system is an example of an organ system. It is responsible for digesting and absorbing food. It consists of a number of organs including the stomach and intestines.

Topics in this Section

  • The cell: structure and functions
    • Plasma membrane
    • Organelles
    • Cell division
    • Mutation
    • Transport of substances across cell membranes
  • Tissues
    • Epithelial tissue
    • Connective tissue
    • Muscle tissue
    • Nervous tissue
    • Tissue regeneration
    • Membranes
    • Glands
  • Organization of the body
    • Anatomical terms
    • The skeleton
      • Axial skeleton
      • Appendicular skeleton
    • Cavities of the body
      • Cranial cavity
      • Thoracic cavity
      • Abdominal cavity
      • Pelvic cavity
  • Disorders of cells and tissues
    • Neoplasms or tumors
      • Causes of neoplasms
      • Growth of tumors
      • Effects of tumors
      • Causes of death in malignant disease