Vanderzyden

MrD,

Despite your endorsement by Rick, your "improvement" fails a preliminary, superficial design review:

Major problem right from the start, as I explained in my first response. How are you going to negotiate the breastbone, ribs, pericardium, lungs and/or diaphragm in order to make this attachment robust and yet easily disconnected? How will you redesign these other organs/components to accomodate this new plumbing?

Also, with this configuration, how will you accomplish the management of fluid pressure, before and after the baby is born? In particular, how will you prevent the higher pressure of the umbilical flow from inflating the lungs? Since you have placed the junction downstream of the heart, how will you redesign the heart so that it (1) handles the significantly different (reverse) pressure load and (2) adjusts properly when the baby begins to breathe for himself?

Higher velocity, relatively lower pressure blood flow to the various regions of the lungs, perhaps?

Yes, there would potential for fewer defects associated with the ductus arteriosis. But you have introduced significantly greater complications. And, despite my explicit mention of it, you have not avoided the mixing of oxygenated and deoxgenated blood, which still occurs in many places in your "redesigned" system.

Vanderzyden

lpetrich

I don't see how Vanderzyden's "problems" are big disasters, because the existing arteries and veins already go through the pericardium, and umbilical blood vessels can easily attach to the pulmonary vessels once they are past the pericardium.

As to getting past the ribcage, the navel could be at the lower end of the breastbone, meaning that the umbilical blood vessels could follow the breastbone to it.

And this does not address such questions as:

Why the heart starts out with only a single blood path instead of two; it has to internally split into two sub-hearts.

Why the initial embryonic circulation is the fishlike arrangement of
heart -> ventral aorta -> aortic arches -> two dorsal aortas
and why it has to be extensively rearranged

Why jaws are made from the frontmost gill bars

Jack the Bodiless

Vanderzyden:
I think this remarkable claim deserves its own thread. Shall I start one to discuss this?

Or will you run away again?
He will never have to. There is no God. Period.

MrDarwin

No time to address this in depth today, so perhaps you, with your apparently vast knowledge of this topic, can tell me why blood coming from the placenta is under "higher pressure"? Higher than what? Precisely where and how is this pressure being generated?

Again, could you please point out precisely where this mixing will occur?

BTW you didn't answer my question about childbirth and doctors. Will you depend on this system running smoothly and optimally when the time comes, or will you prepare for possible problems, just in case?

[ October 18, 2002: Message edited by: MrDarwin ]

[ October 18, 2002: Message edited by: MrDarwin ]</p>

MrDarwin

I think a better position would be just above the collarbone, preferably on the left side, which would provide a direct route to the heart. A secondary benefit of this position is that it would also reduce the risk of herniation, which occurs because the bellybutton (a weak point between the muscles) is low on the body and subjected to pressure from the weight of internal organs.

Dr Rick

You definitely should have spent more time analysing it to avoid posting the mistakes you made.

<strong> This isn't even a minor issue; we doctors routinely and easily access the thoracic vasculature with trocars and catheters above and below the clavicles. The thorax is not solid, there are lots of avenues to access the vasculature, the heart and the lungs through it, including between the ribs and above the sternum.

<strong> We doctors don't have to redesign the thorax every time we insert a central line or catheter into the heart, lungs, subclavian vessels, or aorta; MrDarwin's intelligent design would not require any such reconfiguration, either.

<strong> Infant lungs are inflated by negative inspiratory pressure just as yours are, not by blood flow.

<strong> The pressures would not be reversed.The direction of blood flow is maintained by the heart valves, not the placement of the umbilical blood vessels.

<strong> Nope

<strong> MrDarwin's design is more better than the one we acquired through evolution.

Vanderzyden

Rick,

Your reply doesn't really address what I said, and it is merely a collection of claims. Care to explain in detail, as I have done?

Anyway, before I go to the trouble of responding in kind, I'd like you to also respond to this:

More better? We doctors? You are making claims about surgical arts. Aren't you a physician?


Vanderzyden

Kevin Dorner

This from a theologian who has just spent the last several months telling several real scientists how incorrect they are.

Dr Rick

You have not explained anything in detail. You have merely posted easily refuted nonsense about non-extant and totally imaginary difficulties over accessing the very readily accessed thoracic viscera and vasculature in an ignorant attempt to discredit a genuinely intelligent fetal circulartory design that is superior to the evolutionarily-driven one we humans actually have.

<strong> I am.

I'm also on-call this weekend or else wouldn't be wasting a beautiful Colorado day responding to creationist drivel.

Rick

[ October 19, 2002: Message edited by: rbochnermd ]</p>

Vanderzyden

So, you're not a surgeon, correct? Then why do you spout off as you do?

Tell me, if you and MrD are so capable of improving the design of the CV system, then why haven't you shared your ideas with the bioengineering community. I'm sure they'd love to hear from you.


Vanderzyden