02.02 Levels of Structural Complexity

There are many levels of structural organisation within the human body. In our body the simplest building blocks are atoms which combine to form more complex molecules. Molecules connect to formorganelles, which work together to form cells, the smallest living units within the body. Cells may function individually but often group together to form structures called tissues. Complexity continues toincrease as different tissue types come together to form organs, leading to organ systems and eventually the most complex structure – a living organism. See Figure 2.1.

Figure 2.1 The levels of structural organisation within the human body (Copyright, QUT)