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shadows of echoes of memories of songs
Is it a bird? Is it a badger?
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jinty From: jinty Date: November 13th, 2010 05:12 am (UTC) (Link)
Actually the foetal heart works differently to the adult heart, so the flow of blood is definitely different - whether the structure is visibly different I'm not sure off-hand. In the foetus, the blood doesn't need to go through the lungs as it's already oxygenated by the mother, so although the baby *has* a four-chambered heart I think the blood only *flows* through two of them in utero. Then when the baby's born, things need to change in the heart - physically! - super-fast in time for the first breath. Pretty awesome! I'll see if I can find a link. Here's one that looks good...

Edited at 2010-11-13 05:19 am (UTC)
aldabra From: aldabra Date: November 13th, 2010 08:58 am (UTC) (Link)
Wow. I don't think I knew that.
k425 From: k425 Date: November 13th, 2010 10:09 am (UTC) (Link)
k425 From: k425 Date: November 13th, 2010 10:06 am (UTC) (Link)
I think it's the first breath that actually initiates the physical change, but it's a long time since I studied neonatal heart problems!
jinty From: jinty Date: November 13th, 2010 11:44 am (UTC) (Link)
The link above says that cutting the cord precipitates various changes in pressure. I must admit that when I wrote the comment I didn't know as much as I did after I read the link properly - I had this vague idea of valves slamming shut on birth, somehow!
julietk From: julietk Date: November 13th, 2010 02:17 pm (UTC) (Link)
I read that and thought "that implies that cutting the cord is *required*, which is not the case (as per various forms of natural third stage including lotus birth). But I guess that if you *do* cut the cord, that precipitates the pressure change; and otherwise when the cord stops pulsing by itself that'll do it.

Thank you for the link!
j4 From: j4 Date: November 13th, 2010 10:24 am (UTC) (Link)
Crikey, that's incredible! Thanks for the link.

I am starting to wish I'd actually listened in biology classes at school. :-}
jinty From: jinty Date: November 13th, 2010 11:47 am (UTC) (Link)
Ah but you will learn all sorts of cool things that they never covered in biology anyway - I liked finding out that the umbilical cord contains something called "Wharton's Jelly" which sounds very much like a Victorian brand to me!
shermarama From: shermarama Date: November 13th, 2010 08:34 pm (UTC) (Link)
There's a problem that some scuba divers can suffer from, where the shunt hole didn't grow over; it doesn't necessarily cause a problem in adults depending on the size of the remaining hole, but once you start messing around with breathing at several times normal atmospheric pressure, it can cause decompression sickness. I know a couple of divers who have had to have surgery to have the hole patched...
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