[⪠INTRO] The human body is an incredibly complex machine
made up of systems of organs all working together to keep things humming along smoothly. So youâd think that taking anything out
would make the whole thing break down. But of course, lots of people live without
some of their organs. Like, youâre better off without an appendix
if itâs giving you a problem, for example. And you can afford to lose all kinds of more
important organs, too, like a giant chunk of your liver or even an entire lung. Because yeah, your body is a finely tuned
machine â if you donât mind me saying so â but it also has a bunch of redundancies
that allow it to adapt to some pretty extreme changes. So here are just a few of the bits you can
live without. Number one, the brain. You didnât think we were gonna go there! Of all of the organs in the human body to
lose, even partially, you would think that the brain would be a total dealbreaker. I mean, it controls or coordinates basically
everything else. But it turns out that sometimes, itâs better
to live with just one hemisphere â half a brain, in other words. Like when people have a kind of epilepsy where
seizures stem from one side of the brain. This can happen with some developmental brain
disorders, or with rare conditions like when one brain hemisphere is abnormally large. One-sided seizures are often difficult to
treat, and they can be debilitating. So sometimes doctors recommend a hemispherectomy:
the removal of some or all of the half of the brain thatâs affected. Itâs a very rare, extreme operation, obviously,
but when itâs successful, it can result in a relatively normal life. After a hemispherectomy, between 50-90% of
patients become completely seizure free. They do experience some paralysis in the half
of the body normally controlled by the missing brain hemisphere, but most are still able
to walk if they could before the procedure. And the surgery doesnât usually result in
cognitive deficits, either. Younger patients tend to have fewer side effects
because the remaining healthy hemisphere is still developing, allowing it to compensate
for whatâs missing. Still, itâs a difficult procedure with major
risks, so doctors donât just chop out half of somebodyâs brain without carefully weighing
other options. But the idea that you can lose half of your
brain and still be alive at all is pretty incredible. You might even say itâs ⌠mind-blowing. Breathing is another thing thatâs kind of
essential for human life, so you would think that losing a lung would cause a lot of problems. But you can get by just fine with just one
lung. Lung diseases like chronic obstructive pulmonary
disease, cancer, or tuberculosis can wreck someoneâs lung tissues. So in some cases, part of a lung or even the
entire lung will be removed in a surgery called a pneumonectomy. When one lung is removed, the extra space
allows other organs to shift a bit, giving the remaining lung some more room to expand. Studies have shown that in some animals like
dogs and rats, the remaining lung can actually grow new alveoliâthe little sacs where gas
exchange happens. Itâs thought that children who get a pneumonectomy
might also do this since their lungs are still developing. But in adults, itâs more likely that the
alveoli just stretch and expand a little to move more air through. Ultimately, one lung is able to do about 70-80%
of what two lungs can, and that is usually enough. Depending on age and other health factors,
it might be a bit more difficult to do strenuous activities, but some people who have had this
surgery go on to run marathons, which is more than I can say for me. Your stomach has to be tough enough to mush
around your meals in gastric acid before passing them along to the small intestine. So itâs fairly resilient. But it can still become impaired or diseased
to the point that the patient needs surgery to redirect the digestive tract around their
stomach or to remove part of it. And in some cases, surgeons perform a total
gastrectomy to take out the whole thing and just connect the esophagus directly to
the small intestine. Oddly enough, this doesnât really affect
the overall process of digestion since most of it occurs in the small intestine anyway. But since there is no stomach to store food
in, patients often need to eat smaller, more frequent meals. Sometimes they also need additional vitamin
supplements for things that arenât absorbed well by the small intestine, like vitamin
B12 or vitamin D. And some patients might develop a side effect
called dumping syndrome, which, no, does not refer to the âdumpingâ that you may be
thinking of right now. Sugars and starches are usually digested in
the stomach, but after a gastrectomy, they âdumpâ straight into the small intestine. Since the intestine isnât used to that,
it recruits water to help break those things down, and a lot of that water comes from your
blood, causing a drop in blood pressure. With dumping syndrome, that can cause all
kinds of unpleasant symptoms after a meal: cramping and bloating, nausea, weakness, dizziness,
and low blood pressure. But generally, dietary changes are enough
to overcome these issues, and people without a stomach get enough calories to go back to
their lives. The spleen, which sits to the left of the
stomach, is also a pretty useful organ. Itâs involved in filtering blood, including
removing and breaking down old red blood cells, and itâs one of the places where infection-fighting
white blood cells are produced. But when bad things happen to someoneâs
abdomenâlike if they get shot or stabbed or get in a motorcycle accident like my father-in-law,
the spleen can rupture. Thatâs super dangerous because it can result
in internal bleeding that could be fatal. The spleen can also cause problems if it becomes
enlarged from an infection, because the swelling can trap and destroy healthy blood cells,
leading to anemia. In those cases, doctors will do a splenectomy,
where they remove part or all of the spleen. Itâs typically considered a safe procedure,
but because of its role in the immune system, people without a spleen are more prone to
infections, especially from certain bacteria. So for people without spleens, itâs important
for them to boost their immune system by taking preventative antibiotics and staying vaccinated. But the redundancy of the human body means
the immune system isnât completely destroyed. And the liver can pick up the slack when it
comes to filtering blood. Speaking of which⌠Your liver does a lotâit processes nutrients,
detoxifies your blood, and produces bile, a fluid that helps digestion. And yet, while you canât have your whole
liver removed, you can donate more than half of it to help someone whose liver is diseased. Whatâs really amazing, though, is that unlike
your other organs, your liver will grow back. Your liver is made of hepatocytes, specialized
cells that donât actively replicateâŚthat is, until some are missing. When a piece of liver is removed, hepatocytes
reactivate and start replicating again, growing new liver cells. Liver regeneration is so efficient that you
can lose up to 65% of your liver and itâll grow back within a year. Just a quarter of a liver can become a completely
new liver in a transplant recipient. Like any major surgery, there are risks and
potential complications. But if youâre in good health and feeling
altruistic, liver donation is a thing that you can do and probably be totally fine afterwards. Tucked underneath your liver is a small, pear-shaped
organ: the gallbladder. Its main job is to store the bile that the
liver produces until itâs needed for digestion. But sometimes, the components of bile harden
into small pebble-like stones, and if those stones become a problem, doctors just yank
out the whole thing. Bile is mostly made up of cholesterol, bile
salts, and a waste compound called bilirubin thatâs responsible for the color of your
poop. In the small intestine, bileâs job is to
help digest fats and break down fat-soluble vitamins like vitamin A and vitamin D. But for reasons that actually arenât well-understood,
the cholesterol and bilirubin in bile can harden into gallstones, which can cause blockages
in the bile duct, the tube that leads to the small intestine. Problematic gallstones are super painful,
and without treatment, they can lead to infections and inflammation and even be deadly. Unlike kidney stones, which can often be peed
out, gallstones donât exit willingly. Sometimes they can be dissolved with medication,
but usually they return after the meds are stopped. So in most cases, the treatment for gallstones
is to remove the gallbladder entirely by performing a cholecystectomy. This surgery was first performed in 1882. A German surgeon noted that other mammals
donât have a gallbladder, so he figured ours probably wasnât too important. And he was kind of right. The bile still gets to your small intestine
without it â it just doesnât get temporarily stored along the way. If your gallbladder is removed and the surgery
goes smoothly, usually all you have to show for it is a tiny scar and maybe a little bit
of extra indigestion. Each of your kidneys is made up of more than
a million filtering units called nephrons, which remove waste and excess fluid from the
blood. If that doesnât seem too important to you,
just imagine what would happen to your house if you couldnât take out the trash for a
couple months. In your body, increased levels of waste can
cause vomiting, diarrhea, dehydration... The whole body can swell, increasing blood
pressure and imparing breathing. And chemical imbalances from improper fluid
management can lead to serious issues like bone and muscle loss. Ultimately, kidney failure can be fatal. Yet, you only really need one of your kidneys. Each day, a pair of kidneys filters about
150 liters of blood to produce about a liter and a half of urine. But even one healthy kidney can do all that
work on its own, which is why live kidney donation is a thing. When one kidney is removed, the other kidneyâs
nephrons compensate by getting bigger so they can each do more filtering. It becomes just as effective as two kidneys
would be. And weirdly, leaving a bad kidney or even
two inside of you isnât a problem, either. Recipients donât always get their faulty
kidneys removed, so they actually end up living with a total of three kidneys, even though
only one is doing all of the work. Obviously, your body works best and is the
healthiest when all of the parts are present and functioning. But it is definitely possible to live a healthy
and relatively normal life without some organs, because the human body is incredibly good
at adapting to change. Remove an organ or two, and it just takes
it in stride, itâs like, âIâm gonna be one big lung now, Iâm fine!â I mean, it doesnât look that impressive,
I donât think, but it is pretty wonderful, thank you body! Thanks for watching this episode of SciShow. If you liked hearing about your various removable
body parts, you might also enjoy this episode on how some people have bits replaced with
animal parts. [⪠OUTRO]
Chronic alcohol consumption causes cirrhosis though. It's scarred meaning it won't regrow. You need someone else's liver if you don't wanna die in your own waste. Off note but I really wish the spleen was added to the game and functioned like the kidney now with the kidney taking up some other new role. I also wish there was organ rejection in the game.
It was never a matter of "need" :).
I'm a bot, bleep, bloop. Someone has linked to this thread from another place on reddit:
If you follow any of the above links, please respect the rules of reddit and don't vote in the other threads. (Info / Contact)