> > On 16 Feb 2011, at 15:20, Lux, Jim (337C) wrote: > > > <biologist mode on> > Actually, I'd quibble with that statement about redundancy. On the > system level, there's very little redundancy in most [animal] > organisms. You only have one heart. You only have one aorta, stomach, > oesophagus and so on. Even when some things are paired, the loss of > either one (such as severing a carotid or femoral artery) can in many > cases result in total organism failure. :-)
Re. carotid arteries, that is not actually true. Back when I was but a cub HPC type, working in medical imaging, a colleague was doing MRI Angiography studies of the Circle of Willis. This is a 'ring main' at the base of the brain, where the carotids connect in a ring. Biology has built in redundancy there, and so if you lose a carotid your brain will continue to get blood (assuming you don't bleed to death). Some people have a congenital malformation in the circle of Willis, and it is not complete. Brain surgery for such people is very risky, so finding this out is important. Re. hearts, there was a fascinating documentary in the Horizon series on Monday (Vaelntine's day). A lab somewhere has managed to remove all the cells from a heart, leaving the connective tissue and valves making what they call 'ghost heart'. They are experimenting with repopulating the heart tissue with stem cells, so your transplant heart would be effectively your own, and not rejected. Moving this back on topic, as usual there were a lot of whizzy visualisations, it s a pity that documentaries like these show the cpictures but don't explain in depth what the colour scales mean. The contents of this email are confidential and for the exclusive use of the intended recipient. If you receive this email in error you should not copy it, retransmit it, use it or disclose its contents but should return it to the sender immediately and delete your copy. _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
