Organs You Can Live Without: Could You Really Lose Half Your Brain?

Picture waking up on an operating table while the surgeon reads from a clipboard listing 12 of your organs, starting with the appendix and ending with half your brain. This post goes down that list one organ at a time: what it does, why people lose it and what living without it costs. Everyone here had a surgeon, a reason and a recovery team, so please don't try any of this at home, or anywhere else.

The appendix: a bunker for gut bacteria

The appendix is a finger-sized dead end on your gut, and its main hobby seems to be exploding on a Saturday night. You might already be without one, since one in eight American men and nearly one in four women lose theirs.

It may not be useless. Scientists think it's a safe house where good gut bacteria hide while a stomach bug flushes everything else out. If surgeons leave a stump behind, it can flare up again, and doctors really do call that stumpitis. Otherwise, people notice no difference. This one is free.

The tonsils: bouncers at the back of the throat

Your tonsils are two lumps at the back of your throat that check germs at the door. In 1959, America took out about 1.4 million of them, mostly from children, because doctors blamed tonsils for nearly everything. Today it's about half a million a year, for repeat infections or sleep apnoea, a breathing problem during sleep. Other immune tissue covers the shift. The cost is up to two weeks of whispering and all the ice lollies you want.

The gallbladder: the bile tank

The gallbladder stores the bile your liver makes and squirts it out the moment a burger lands. Gallstones can clog it, and up to one in five adults is carrying gallstones right now. One woman in India had 12,000 removed, which is less an organ and more a gravel driveway.

Without the tank, bile drips straight into your gut all day, like a leaky tap. That's fine for a salad. After a big greasy meal, though, your gut can complain for weeks or months. Doctors call the gallbladder a luxury rather than a necessity. The cost is going easy on the cheeseburgers.

The spleen: the blood recycler

The spleen is about the size of an avocado, tucked behind your ribs, where it filters old blood cells and makes germ fighters. It's wrapped in a layer about as tough as tissue paper, which makes it the organ most often hurt when your belly takes a hit.

Lose it and your liver covers many of its jobs, but your risk of a serious infection stays two to three times higher. The cost is vaccines, often daily antibiotics and a very serious attitude to fevers.

One kidney: the other one steps up

Your kidneys filter up to 150 quarts of blood a day. Lose one and the other simply grows bigger and does the work of both. That's why healthy people can give one away on purpose. About a thousand people in Britain donate a kidney each year, and fewer than one in 200 get serious kidney trouble later. The cost is more water, less salt and a yearly check-up.

The thyroid: a gland swapped for a pill

The thyroid is a butterfly-shaped gland in your neck that sets your metabolism, temperature and heart rate. It's your body's thermostat, so you'd expect the whole house to go cold without it. Instead, the fix is one small pill called levothyroxine, one of America's most prescribed, with about 81 million prescriptions in 2023. The cost is one pill a day, for life. Don't break the streak.

One lung: your organs move house

Your lungs aren't twins. The right one has three lobes and the left only two, because the heart called dibs on the space. When surgeons take out a whole lung, usually because of cancer, you'd expect a big empty hole. Instead, air fills the space first, then fluid, and then your heart and diaphragm slowly slide over into it. After months of puffing, people get back to normal life, just slower. The stairs win more often.

The stomach: six small meals a day

The stomach churns your food in acid. People mostly lose it to cancer, but one case is a warning. In 2012, an 18-year-old in England drank a liquid nitrogen cocktail. It burned through her stomach, and surgeons had to remove it.

Without a stomach, surgeons connect your food pipe straight to your small intestine. You can still eat normally, just in six small meals a day instead of three, which is a very hobbit way to live. Eat too fast and food lands in the intestine too early, which is called dumping syndrome. You also can't absorb vitamin B12 any more, so you need regular jabs.

The colon: losing the body's towel

The colon is five feet of tube that wrings the water back out of what's left of your food. Think of it as your body's towel. People can lose it to cancer or a bowel disease. Sometimes that means a bag. Other times, surgeons fold the small intestine into a J-shaped pouch, so you still go the normal way.

With no towel, things stay loose, which can mean five to ten trips to the toilet a day. The cost is knowing every toilet in town. And because the appendix hangs off the colon, its little bunker goes too.

The bladder: a new one made of gut

Your bladder holds up to about two cups. People usually lose it to cancer, and one option afterwards is a bag. The other is stranger. Surgeons sew about 40 cm of small intestine into a ball, making a brand new bladder out of gut.

It has no bladder nerves, so it never tells you it's full. People wee by the clock instead, every two hours at first and later up to every six. Wait too long and it can even burst. Still, over 90% get daytime control within 18 months.

Most of your liver: the organ that grows back

Every organ so far could go completely. The liver can't. It's about the size of a football, has over 500 jobs, and you can't live without it. But surgeons can remove up to 70% and it grows back. It's the only organ that regrows to full size.

In donors, the liver is back at work in about two weeks and back to 90% of its size in six months. A living donor gives away a piece, and both pieces grow into working livers. In Greek myth, an eagle ate Prometheus's liver every day and it grew back every night. The Greeks were weirdly onto something.

Half your brain: the other half rewires

Your brain is supposed to be you, so losing half of it sounds like losing half of yourself. Yet for children with seizures that nothing else can stop, surgeons remove or disconnect half the brain in an operation called a hemispherectomy. Of 111 children at Johns Hopkins, 86% ended up free of seizures, or nearly. In one study, all of them could walk.

The missing half doesn't regrow like the liver. The remaining half rewires instead. Caltech scanned six adults who'd had the surgery as children and found all the usual brain networks, packed into one half and wired even more tightly than normal.

Christina Santhouse had the operation as a child in 1996 and grew up to be a speech-language pathologist, teaching other people to talk. The honest cost is that one hand stays weaker and you lose half your field of view.

The short version

• The appendix and tonsils can go with almost no lasting difference, and losing the gallbladder mostly means easing off greasy food.
• One kidney or one lung can carry the load, and surgeons can build a new bladder out of small intestine.
• The liver can lose up to 70% and grow back, while after a hemispherectomy the remaining half of the brain rewires.
• Look after the parts with no backup, and tell your family if you'd want to be an organ donor.