- Routing of nerves and fluid pathways in the human body resembles the tangle of wiring and pipes in an aging house, a heritage from fish and amphibian ancestors.
- The tube through which sperm passes forms a roundabout loop that can lead to hernias, a result of major anatomical changes that occurred as we evolved from fish.
- Nerves that are inherited from fish and travel from the brain to the diaphragm can become irritated and trigger hiccups, a closing of the entryway to the windpipe, an action that itself is a hand-me-down from amphibians that breathe with both lungs and gills.
I started teaching human anatomy at the same time my university renovated my laboratory. As it turns out, this coincidence could not have been more propitious. Teaching anatomy for the first time can be a struggle, and it is not just because there are an enormous number of names to learn. A glimpse inside the body reveals structures left inside of us during the course of evolution, which often seem a confused jumble, with arteries, nerves and other structures taking odd paths to get from one part of the body to another.
While I was struggling to understand the body’s internal structures, I was given space in a 100-year-old building that needed to be renovated into a modern laboratory. When we opened the walls to look at the plumbing, wiring and other mechanicals, we saw a tangle that made no apparent sense; cables, wires and pipes took bizarre loops and turns throughout the building. Nobody in their right mind would have designed my building to conform to the snarled mess we saw when the wall was removed. Constructed in 1896, the utilities reflect an old design that has been jury-rigged for each renovation done over previous decades. If you want to understand the twisting pathways for a cable or a pipe, you have to understand their history and how they have been modified over the years. The same is true for structures in the human body.