The patterns of exchange in our bodies are the same as those in a tree, a watershed, an ecosystem, or an economy. Understanding the patterns of how one of these systems works, we understand how all of them work, and how to work with them. This is why patterns are powerful: they enable us to understand and work in very different media and across vastly different scales.
Living (biological) systems work differently than purely physical systems. Being based on exchange rather than action and reaction they can only be understood as flows.
Flows are understandable only as patterns.
All living things, from the tiniest bacteria up through all the plants and animals, breathe in and out, eat and secrete waste, trade.
There must be some kind of difference for exchange to happen: something to exchange and a boundary to exchange across. Trees make exchanges across the earth/atmosphere boundary, rivers across the land/sea boundary, mosquitos across the human/mosquito boundary, international trade across international boundaries.
This is why trees, rivers, arteries, and trade networks all branch. Branching creates the greatest possible surface to volume ratio. This enables as much exchange as possible.
Financial, hydrological and circulatory systems all depend on the continuous cycling of resources to insure adequate supply. Pooling of all of the money or water or blood only happens when the system fails. It is only the continuous exchange of these resources that makes them valuable.
All living things are like a holiday meal, a farmer's market or a music festival. People, money, ideas, and food converge temporarily for exchange and enjoyment. Some thing comes into being for that time, but the exchange and relationships are the point. The same is true of my body, a tree, or a mountain range.