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Tunicate – Part 1

By Jon Zahourek

We vertebrates depend on our anatomy to be alive. Once our ancestral fish developed jaws and fins, our anatomy can be described as composed of five functional organ systems.

First, our digestive system, contained in its own sac within our bodies, digests food to fuel our metabolism.

Second, our lungs, also contained in its own separate sac, extracts oxygen from our environment in exchange for carbon dioxide.

Third, our heart circulates the energy through tubing to every cell in our bodies.

Fourth, the bones of our musculoskeletal system house and protect our internal organs. Bones are the levers—each joint a fulcrum that provide all vertebrates the means of biomechanics in movement. Muscles biomechanically pull the levers of the skeleton into movement and mobility.

Fifth, networks of our nervous system not only coordinate the functions of our muscles, they also regulate our internal organs. Our central nervous system of spinal cord, brain, and proprioceptors collaborate in mind through which we comprehend the world around us.

Nevertheless, 40 years ago my first insight into anatomy was only concerned with the human skeletal system. I realized that the human body is less a catalog of parts, it is a cooperative of subsystems: axial, branchial, pectoral, and pelvic.

The sheer variety of vertebrates makes it easy to assume that these different species of animals are unrelated. In mammals like us, though, the anatomy of our shoulder and of our hip appear to be quite different from one another. However, in anatomical form and biomechanical function, they are strikingly similar.

Intrinsic & Extrinsic

When a muscle’s attachment sites are exclusively within a single subsystem, I call them “intrinsic” to that subsystem. In other words, they belong only to a single subsystem itself. Some muscles are “extrinsic.” These muscles cross from one subsystem to another.

I first set out, in forming clay muscles one-at-a-time onto my early Maniken® model, to shape the functional musculoskeletal anatomy that’s intrinsic within each subsystem as well as the extrinsic muscles between the subsystems. These two components add up to a simple logic of the whole system.

There is logic in how these subsystems work. There is also logic in how the subsystems relate to each other, too, of course.

The logic is the result of evolution. And it can be traced all the way back to our ancestral, jawless fish. All the way back to the tunicate.







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