A man gets shot in the heart. He has very little time to get a new one.
If he had a backup heart linked up to the correct arteries, then failure of the primary, the real heart, could trigger the auxiliary, the artificial one.
Blood loss could still be a problem because a backup 2L of blood might be difficult to carry with you at all times. A better solution to blood loss might be a kind of patch that bonds to skin.
I also want a backup oxygen exchanger, since even a small impact or puncture renders lungs inoperative. People who don't want to carry around the general-system large network of artificial vessels and fans could opt for a smaller dedicated-system unit for brain oxygen only, since cell death elsewhere is more tolerable.
Attaching enough equipment to backup every organ system (except the brain, of course) would probably require a powered exoskeleton among other things. As long as you have the metal frame, you could add armor plates and other vehicle-type features.
Auxiliary Body Systems of the exoskeleton variety become facultative; you can leave your exoskeleton and aux systems behind by unplugging the connections, which have appropriate valves to prevent your insides from spilling out. That way you can perform activities that would be otherwise impeded by wearing a large metal body suit.-- Ketchupybread, Apr 04 2009 Space Marines details http://warhammer40k.../wiki/Space_MarinesSection 1.3 details back-up and augmentation implants. [Aristotle, Apr 07 2009] /I've long wondered how much gas exchange could occur across the intestinal mucosa./ Bung_20LungBUNGCO has a place for you in our Bung Lung Division! [bungston, Apr 10 2009] next up: ammunition that takes care of both primary and backup systems.-- loonquawl, Apr 07 2009 Certainly imaginative enough although I seem to recall that Games Workshop's Space Marines seem to have some or most of these back-up systems for when they are involved in future warfare.-- Aristotle, Apr 07 2009 Space Marines came to my mind too..."the Space Marines (or Adeptus Astartes) are elite soldiers enhanced to superhuman levels through brain therapy, surgical modifications, and hypnotic indoctrination. "([Aristotle] beat me to the link.)-- Jinbish, Apr 07 2009 Blood could be stored in a larger but less active spleen. However, the "less active" bit is crucial. A larger spleen is automatically more active, which leads to problems. There's a lot of room for it to enlarge into though, as it can be quite a bit bigger without being noticeable. That would also make it a bigger target. I've long wondered how much gas exchange could occur across the intestinal mucosa. Maybe you could breathe through your anus if you had COPD, or have a sterile oxygen supply in the peritoneum.The other thing is, certain sea cucumbers defend themselves against predators by literally puking their guts up over them. Some of these then grow a new set, but others have a spare one for that purpose. If people could be persuaded to have a separate set of organs, they could maybe defend themselves in a combat situation by chucking up a few kidneys and a couple of metres of colon on their assailant. If they also everted their stomachs, they could also dump hydrochloric acid on them, which might be quite an effective deterrent.-- nineteenthly, Apr 07 2009 It's more memorable than the rest, [Bigsleep].-- nineteenthly, Apr 07 2009 Although [nineteenthly]'s idea of being able stun someone with a well-aimed projectile kidney, sacrificed in order to defend yourself, certainly has some merit.-- Aristotle, Apr 08 2009 Thanks, [Aristotle]. It's sort of like overcompensating, like "Wanna see some blood then, do you? RIGHT!"I thought this was more about biological replacements than bionics. Then again, a biological exoskeleton woud be Kafka-esque.-- nineteenthly, Apr 08 2009 Now I see the idea has already been better thought out in Space Marines.
I reject the claim that these systems are magic. Some artificial organs do exist.
Finally, Nineteenthly's comment and the Space Marines link are so useful and interesting that I won't delete this idea.-- Ketchupybread, Apr 10 2009 Thanks!-- nineteenthly, Apr 10 2009 You got a backup lung. It is the other one.-- bungston, Apr 10 2009 You can't easily wurp them at other people in an emergency though.-- nineteenthly, Apr 11 2009 random, halfbakery