The messy, organic self

[elfs]

areitu recently snarked (at least I think it was snark):

I didn't realize the heart was that haphazardly assembled. Maybe the hobbled together nature of the heart is why nobody can figure out how to make a machine pump do the simple job of pumping fluid.

Well, certainly nobody in his right mind would design a pump quite like the heart.

I mean, consider that the heart is a bellows. A flexible membrane constantly stretches and contracts, suffering mechanical stress with each and every beat, prematurely aging.

To counter that premature aging, every cell of the heart (hell, the human body) has an independent mainetence system, one which does not cross-check with its neighbors in any sort of reliable way. Instead, they all monitor one another and, when threatened by a neighboring cell, go into a destructive, predatory mode, crowding out the problem via inflammation; a response that's a leftover from millions of years ago when our ancestors were barely multicelled organisms. Our body is a colony of cells. Evolutionary success has tamed those cells to stop being quite so competitive, but the body's response to lots of stresses are those that have emerged from co-opting the competitive mechanisms of monocellular existence, and often those responses are worse than the original problem. Cardiac inflammation is a serious disease in its own right.

Scaling up, the kind of infrastructure that supports the heart is insanely overcomplex, the kind of thing that scares the willies out of engineers. It's the sort of thing one sees only in nature, because evolution just layers stuff on top of more stuff.

Watching my heart on the monitor, watching the "valves" and the "pump," I saw that they were nothing of the sort at all. The valves are chunks of flesh, with little fleshy bits here and there, not entirely smooth and simple, but messy, organic, grown, evolved. It's remarkable that it works as well as it does, but one shouldn't consider the layout of the heart and the design of a mechanical pump as analagous.

Comments

[hydrolagus.livejournal.com]

A recent essay (http://www.sciam.com/article.cfm?id=this-old-body) in Scientific American had some notes on the fascinating kludge that is human anatomy.

[areitu.livejournal.com]

After seeing Dr. Jarvik was selling Lipitor on TV and began to wonder why it was difficult to perform the conceptually simple task of pumping blood. It was my colorful way of saying, "You gave me an epiphany about hearts."

[resonant.livejournal.com]

Oddly, we don't really need a centralized heart. Our blood vessels already have the ability to constrict and relax, and some of the vessels also already have one-way valves. With a little genetic engineering to add more valves and to get the epithelial cells contracting in phase, we could have a completely peristaltic circulatory system.

[resonant.livejournal.com]

Also, if I was designing the human body, I'd change the respiratory system from batch mode to continuous flow. If the digestive system worked the same way as our lungs, we'd have to vomit out poo afer eating each meal.

It'd be more efficient to genetically engineer the body so that air would go into the top of one lung, pass into the bottom of the other one, and then exit out through the top. Less dead air space at the bottom, more efficient transfer of gases to and from the bloodstream. If the interlung passage clogged, or if the necessary valve failed, the lungs would just return to normal batch-mode operation.