When we think about structural integrity, we must consider what is necessary for repair and maintenance of structure, and even replication of tissue. In the intestines, it is structural integrity that creates the selectively permeable barrier that allows nutrients to enter the blood stream while excluding toxins and infections. When this selectively permeable barrier is disrupted the result is a “leaky gut,” or what is more properly referred to as “increased gut permeability.” In the cranium, there is the blood-brain barrier, analogous to the gut barrier. This structure prevents the unrestricted exchange of substances between the blood and brain tissue. Structural integrity can also refer to changes at the molecular level when transport proteins and receptors are altered in some way to affect their function.

Transport, beyond the blood circulation and lymphatic system, can encompass all aspects of biology from the whole organism to the individual cell and its subcellular organelles. Transport applies to situations where conveyance from one part to another part is required for function. While this can mean transportation of oxygen in the heme molecules of red blood cells, nutrients and hormones in the blood stream, it can also refer to transport of electrons through the electron transport chain of the mitochondria, the transport of messenger RNA into the cytoplasm where it is transcribed into protein, and the efficiency of transporter molecules in the blood and cell membranes for hormones, fatty acids, essential minerals, and glucose. The modifiable lifestyle factors of Sleep, Movement, Nutrition, Stress, and Relationships should be evaluated for areas of need and corrective measures taken to improve balance within structural integrity and transport in the functional medicine matrix.