26 Brain Controlled Vomiting Reflex
Vomiting is controlled by a specialized “vomit center” in the brain that coordinates a complex chain of reactions throughout the body. When the body detects something harmful, the digestive system slows or shuts down, and signals trigger the stomach muscles to contract forcefully, pushing contents back up through the esophagus. This reflex acts as a protective mechanism to expel toxins or irritants before they can cause further harm.
27. According to the largest study on human penis size, an erect penile length of 6 inches places a man around the 90th percentile. This means he is longer than roughly 9 out of 10 men measured in the study.
28. The philtrum, the groove in the middle of your upper lip, exists in all mammals but serves a more functional role in many animals than in humans. In non-primates like dogs, it is narrower and helps channel saliva from the mouth to the nose through capillary action, keeping it moist. A wet nose improves the ability to trap scent particles, which enhances smell, showing that this small feature plays a key role in animal sensory function.
29. The human skull is one of the least deformable structures in the body and is remarkably resistant to compression. It can require roughly one ton of force to reduce its diameter by just one centimeter, a strength that helps protect the brain from everyday impacts.
30. Many of Leonardo da Vinci’s drawings of the female reproductive system contained major inaccuracies. Because female cadavers were rare in his time, he often studied animals and then extrapolated their anatomy to humans. As a result, some of his illustrations resembled animal reproductive organs more than those of actual human females.
31 Ondine Curse Stops Breathing
Ondine’s curse, also known as central hypoventilation syndrome, occurs when damage to the brain disrupts the automatic control of breathing. Patients can breathe consciously while awake, but when they fall asleep, the subconscious drive fails, causing breathing to slow or stop. This makes the condition potentially fatal without medical support such as ventilators or assisted breathing devices.
32. Ketone bodies can cross the blood-brain barrier, unlike most fats, allowing them to serve as an alternative energy source for the brain. During prolonged starvation, the liver produces ketones from fat stores, which then supply energy to the brain when glucose levels drop. This metabolic shift helps humans survive for weeks, even over 40 days, without food.
33. The older we get, the brain area responsible for filtering background noise and helping us concentrate becomes weaker. This affects tasks like driving, where elderly people may focus too much on irrelevant background movement instead of important objects in the foreground. The result is reduced focus and slower reactions in complex environments.
34. Bones generate piezoelectric signals when mechanical stress is applied, creating tiny electrical charges within the tissue. These signals attract osteoblasts, the cells responsible for building bone, to the stressed area. The osteoblasts then deposit calcium and other minerals there, increasing bone density and strengthening the structure over time.
35. Tampon companies test the absorbency of their products with a device called a Syngyna, a synthetic vagina designed to simulate real use under controlled conditions. Manufacturers run fluid through it to measure how much a tampon can absorb before approving it for sale and labeling.
36 Brain Specialized for Detecting Snakes
The human brain has a specialized region within its visual processing system that reacts strongly to snakes. Studies show this pathway detects snake-like shapes faster than other objects, suggesting an evolved survival mechanism. Researchers believe this sensitivity developed because snakes posed a major threat to early humans.
37. Before modern CPR was developed in the mid-20th century, the primary treatment for cardiac arrest was open cardiac massage, which involved surgically opening the chest to manually compress the heart. Physicians used their hands to keep blood circulating when the heart stopped, a method that was invasive and only possible in clinical settings. The introduction of closed-chest CPR later made life-saving resuscitation faster, safer, and possible outside operating rooms.
38. Studies suggest men process male voices in brain regions associated with simple sounds like machinery, while female voices activate areas linked to music and complex sound patterns.
39. Blood flows through the kidneys at a rate of about 1.1 liters per minute, while the human body contains roughly 5 liters of blood. This means your entire blood supply passes through the kidneys about once every five minutes.
40. People with early Alzheimer’s disease may lose their ability to smell certain odors, including peanut butter. Researchers found that this decline often appears first in the left nostril, leading to a simple “Peanut Butter Test” as a potential early indicator.
41 Humans Retain Ear Wiggle Muscles
Some humans can still voluntarily wiggle their ears using vestigial muscles that once helped our ancestors move their ears toward sounds.
42. A blocked nose is not caused by mucus plugging the passage but by swollen blood vessels inside the nasal tissues. During a cold or irritation, these vessels become inflamed and expand, narrowing the airway and restricting airflow. This is why blowing your nose often does little to relieve congestion.
43. Modern humans carry about 2.5 to 4 percent Neanderthal DNA, but no known Neanderthal Y-chromosome genes have survived. One hypothesis suggests that when modern human women conceived male fetuses carrying Neanderthal H-Y antigens, their immune systems may have recognized those proteins as foreign and ended the pregnancies. If that happened repeatedly over many generations, Neanderthal Y chromosomes could have disappeared even while other Neanderthal DNA remained in the human gene pool.
44. Babies born vaginally tend to develop gut microflora that closely resembles the mother’s vaginal bacteria, while babies born by cesarean section usually acquire microbes that more closely match the mother’s skin. This happens because a baby’s first major exposure to bacteria comes from the body surfaces it contacts during birth.
45. Paraplegics and quadriplegics often lose the ability to sweat below the level of their spinal cord injury. Because sweating is controlled by nerve signals that no longer reach those areas, the body cannot regulate temperature effectively on its own. As a result, they must actively manage heat and cold exposure to avoid dangerous overheating or hypothermia.
15 Most Controversial & Costly Blunders in History
46 Lack of Erections Shrinks Tissue
Without regular erections, penile tissue can lose elasticity and begin to shrink over time. Reduced blood flow and oxygenation cause the tissue to stiffen, which can shorten the penis by about 1 to 2 centimeters.
47. In 1974, a 48-year-old health food advocate named Basil Brown from Croydon, England, died after consuming about 10 gallons, or 37.85 liters, of carrot juice over 10 days. The extreme intake led to a vitamin A overdose, causing severe liver damage that ultimately proved fatal.
48. Studies have found that singers in a choir unconsciously synchronize their breathing patterns while performing together. During slow, structured chanting, this shared breathing rhythm can align their heart rates, causing them to rise and fall in unison.
49. Human eyes have unusually small irises compared to other primates, making the white of the eye more visible. This contrast makes it easier for others to track gaze direction, which supports social communication and cooperation. Researchers link this trait to the cooperative eye hypothesis, suggesting it evolved to help humans share attention and intentions more effectively.
50. Smell is the only sense that does not pass through the thalamus, the brain’s main sensory relay center. Instead, odor signals travel directly to the primary olfactory cortex and limbic areas linked to memory and emotion, often without conscious processing. This direct pathway explains why certain smells can suddenly trigger vivid memories or emotions without a clear reason.
RE: Fact #31 (Ondine Curse Stops Breathing) – That is easily the worst thing to read right before going to bed. Seriously.
RE: Fact #13 (Prometheus and Liver Regeneration Myth) – That’s also because the liver was considered the seat of the soul, life, and intelligence in ancient Greece. It was really all about the intensity of the punishment.
RE: Fact #37 (Open Chest Heart Massage Before CPR) – It’s still done as a last resort sometimes, and it is absolutely wild to watch.
This method is actually preferred during open-chest surgeries because it’s much better at circulating blood, and well, the chest is already open anyway.
RE: Fact #27 (Six Inches Is 90th Percentile) – Yeah, but where do they measure from? The base or the balls? TMI feels a lot more reliable.
If you want to know how it’s measured in these studies, it’s from the base on top.
RE: Fact #18 (Genetic Loss of Wisdom Teeth) – Funny how genetics works. My mom had all four wisdom teeth, my dad had none, and then it’s split between me and my brother. Just luck of the draw, I guess.
RE: Fact #27 (Six Inches Is 90th Percentile) – The average is barely over 5.5 inches, but everyone you talk to claims they’ve got at least 6. It’s confusing because you hear people complain that larger sizes are uncomfortable, but then you see people specifically asking for 7 inches plus. Most guys spend their whole lives worrying if they’re too small, even when they’re told otherwise. I have no idea who is actually telling the truth.
Memory and fantasies play a big role here. I remember reading about a study where women were asked to guess their partner’s size; they consistently remembered current boyfriends or husbands as being an inch or two bigger than they really were, but remembered exes as an inch or two smaller. It seems like women talk up their current partners to make others jealous, which makes everyone think they need to be bigger. It just leaves everyone unhappy.
RE: Fact #1 (Misplaced and Fused Human Kidneys) – Here is another weird kidney fact: when you get a transplant, they don’t bother taking out the original ones if they’re still working at all. They just tuck the new one in there. My dad has three now, and a friend of his actually has four.
RE: Fact #4 (Man With Donor DNA Body) – “Honey your c*m tastes exactly like Dan’s.” “Well it might have something to do with the bone marr-wait what?”
RE: Fact #27 (Six Inches Is 90th Percentile) – I don’t buy it. It feels like every 12-year-old on the internet claims they’re way above that size, so that’s got to be more than 10% of the population.
RE: Fact #4 (Man With Donor DNA Body) – Has anyone used this for a plot yet? The investigators were shocked that the donor DNA had basically taken over his system. It brings up a huge issue where, if someone like this committed a crime, the forensic evidence could completely mislead the police.
RE: Fact #43 (Missing Neanderthal Y Chromosome Mystery) – There is a much grimmer possibility. The humans moving into Neanderthal territory during the time they went extinct could have involved mass rape, which is unfortunately common in warfare.
RE: Fact #12 (Depression Beyond Chemical Imbalance) – It’s still a helpful thing to say if you’re dealing with people who just try to tell you that depression is a sign of being weak or immoral.
RE: Fact #26 (Brain Controlled Vomiting Reflex) – Understanding the science behind this has honestly helped my emetophobia so much. Dealing with that fear for 30 years was exhausting, especially having to explain it to doctors while having a panic attack. To anyone else struggling, it gets better once you learn to rationalize the physical symptoms. I’ve worked really hard to manage it.
RE: Fact #5 (Sunlight Triggers Sneezing Reflex) – I honestly thought everyone sneezed when looking at the sun. I’ve gotten so many confused looks when I mention it, so it’s a relief to know it’s actually a thing.
RE: Fact #19 (Virus Enabled Human Placental Birth) – It’s wild to think that part of what makes human placental birth possible might be ancient viral DNA. The way that protein allowed cells to fuse and keep the mother and fetus from reacting to each other is basically the foundation for how we exist today.
RE: Fact #34 (Stress Generates Bone Growth Signals) – One big issue with using steroids or growth hormones to gain strength quickly is that your bones, tendons, and ligaments don’t get stronger at that same speed.
RE: Fact #5 (Sunlight Triggers Sneezing Reflex) – Yes! Finally, I have proof that I’m not crazy and that light really does trigger my sneezing.
RE: Fact #30 (Da Vinci Female Anatomy Errors) – Da Vinci was a genius, but anatomy wasn’t his strong suit. He wasn’t exactly a pioneer there. A good understanding of surgery had been around since 150 AD; a famous anatomist named Galen was performing brain surgery and removing cataracts back then. By the time Da Vinci was doing dissections, experts were already putting together manuals like De Fabrica that were light-years ahead of his work. It is a mistake to think he was brilliant at everything. He was a great artist and very curious, but not every project he touched was a success.
Virgin Da Vinci vs. Chad Galen: Da Vinci: Has never seen a woman’s insides, has to guess based on animals. Sketches mechanical devices because they don’t judge him. Designs a tank that never actually sees combat. Galen: Lives in 150 AD and has to be tough every single day to survive. Operates on live patients and writes books to share knowledge with his bros. Has worked on an open brain, knows exactly how it works, and gets any woman he likes.
Da Vinci didn’t know much about women, that’s for sure. He was nearly put on trial for sodomy and never married. Instead, he spent his adult life with his very special friends Salai and Melzi, two handsome young men who inherited most of his wealth. Totally not gay, right?
RE: Fact #45 (Spinal Injuries Disable Sweating Control) – True. I once had a customer who was severely paralyzed and had to steer his chair with his mouth. One hot day, he came into my shop and asked if I could spray him down with water to help him cool off. It was a bit awkward at first, but I realized it was a huge help for him. Honestly, the whole setup felt like something straight out of a bizarre movie.
RE: Fact #33 (Aging Brain Loses Focus Filtering) – I’m an older guy, and playing video games helps a lot. You have to pay attention or you die in-game, and my driving has definitely improved since I started gaming.
I’m also an older guy who has gamed his whole life, and this is 100 percent accurate. Games help with problem-solving, but the boost to spatial awareness is huge.
RE: Fact #41 (Humans Retain Ear Wiggle Muscles) – My mom and I can both do this. Whenever I wiggle my ears, it causes a lot of vibration and a loud rumbling sound that only I can hear.
That’s interesting. I can wiggle and rumble, but they’re two totally different things for me. I can do both at once, but doing one doesn’t trigger the other.
RE: Fact #10 (Black Cab Drivers Brain Changes) – I read something years ago about how being a cab driver is one of the most mentally demanding jobs because you’re constantly using all your senses to learn the city.
RE: Fact #1 (Misplaced and Fused Human Kidneys) – Some people are born with only one kidney and don’t even realize it until there’s an actual problem.
RE: Fact #35 (Syngyna Device Tests Tampon Absorbency) – Jeez, next thing you know there’ll be a fact about how toilet paper companies test absorbency with a Synasshole.
RE: Fact #22 (Gunshot Victim Revealed Digestion Science) – They actually still do this for research sometimes. They use rumen fistulas to study cow nutrition. It looks like a little porthole on the side of the cow.
RE: Fact #13 (Prometheus and Liver Regeneration Myth) – Prometheus was an immortal titan, which is why his liver grew back. The Greeks didn’t know about biological regeneration; they were just creating a brutal punishment for him. Plus, the liver held a lot of spiritual significance back then.
RE: Fact #44 (Birth Method Shapes Baby Microbiome) – People have started using vaginal swabbing to transfer that bacteria directly to babies born by C-section to try and address this.
RE: Fact #18 (Genetic Loss of Wisdom Teeth) – I’m one of those mutants! I love bragging about it, honestly. Feels like I definitely got lucky.
Me too! Although some people act like it’s impossible to be born without wisdom teeth when I tell them.
RE: Fact #3 (The Rare Condition Hematidrosis) – Pretty sure this is what happened to Jesus in the Bible. I’m not a believer, but it was cool to learn that this is actually a real thing that can happen.
RE: Fact #34 (Stress Generates Bone Growth Signals) – This is why impact exercises are so important. There was a story about a top cyclist who broke his hip from a minor fall and realized his bones were like those of an 80 year old even though he was in peak shape, just because he only cycled. He started cross-training with high-impact stuff and his bones thickened up.
RE: Fact #9 (Daily Production of Stomach Acid) – I got sick once and my intestines stopped moving everything through, so my stomach would completely fill with gastric juice in like two hours. I’d throw up, and then it would just start all over again. After doing that five times, I had to hit the ER. It was miserable, I was on a stomach pump for two days until it finally cleared up.
RE: Fact #47 (Carrot Juice Vitamin A Overdose Death) – “He was also consuming vitamin tablets by the handful and was found to have taken 70 million units of vitamin A in 10 days.”
RE: Fact #46 (Lack of Erections Shrinks Tissue) – Periodic erections and emissions while you sleep are totally normal, so don’t worry about it. It is just your body keeping things healthy by cycling blood and oxygen through those tissues. If you are really curious if it is happening, you can test it by wrapping a roll of postage stamps around the base and taping the ends. If the perforation is torn when you wake up, you know it worked.
RE: Fact #7 (Diaphragm Singing Caused Vocal Damage) – The research on this is really interesting. They found that the shift in vocal technique forced by heavy operatic roles caused a lot of damage. They observed a legendary soprano whose diaphragm movement was super quiet and efficient, which was the opposite of how modern singers are taught to push for power.
RE: Fact #22 (Gunshot Victim Revealed Digestion Science) – That would drive me insane. Wouldn’t having a literal hole in your stomach make you super prone to infections?
I’d think so, but apparently the stomach acid helped keep the area around the fistula relatively sterile. Still, definitely more of an infection risk than a normal stomach.
RE: Fact #15 (Opposite Sex Heart Transplant Risk) – I wonder if the size difference is the main reason. Men are usually larger, so maybe it’s just that putting a heart meant for a larger person into a smaller one, or vice versa, causes issues with how it fits in the chest cavity.
It’s not just size. Men’s and women’s hearts are biologically different when it comes to tissue density, heart rates, and even how symptoms for heart attacks manifest. You can actually tell if a heart is male or female just by looking at the organ itself.
Whenever the Grinch’s heart grew three sizes, he dealt with a lot of fluid retention and trouble moving around, for what it’s worth.
RE: Fact #23 (Danger Triangle Deadly Infections) – You’d think they could come up with a more scientific name than The Danger Triangle.
RE: Fact #25 (Armstrong Limit Boils Lung Fluids) – Your blood doesn’t actually boil because your circulatory system is under pressure from your heart. Eventually, though, the vacuum would pull your blood into your lungs, which would definitely cause major issues.
RE: Fact #23 (Danger Triangle Deadly Infections) – As someone who has dealt with acne for 15 years and has popped plenty of pimples in that danger triangle area, I’m glad to report I’m still alive and kicking.
Yeah, kind of like how everyone says reading in the dark ruins your eyes or masturbation makes you infertile. But who knows if the danger triangle thing is actually a legitimate threat?
RE: Fact #18 (Genetic Loss of Wisdom Teeth) – Basically, every trait humans have or don’t have is the result of some random mutation from thousands of years ago.
RE: Fact #20 (Morning Erections Maintain Penile Health) – Scientists studying boners must have the most awkward time at conferences. Imagine explaining that your big research breakthrough is just monitoring men while they sleep.
RE: Fact #42 (Nasal Congestion Caused by Blood Vessels) – Tell that to the times I’ve blown my nose and had a booger explosion that finally cleared everything out.
RE: Fact #31 (Ondine Curse Stops Breathing) – I dealt with that for a few weeks while I had Covid. For a few hours at night, my body just stopped breathing automatically. I had to sit there and consciously focus on every breath until morning so I could drive to the hospital. Luckily, it came back before sunrise. It happened in shorter bursts, too, but those few hours were intense. It was weird how relaxed I stayed; I have no idea why I didn’t panic, since I had no clue what was happening. I’m just glad it was temporary and not a permanent issue.
RE: Fact #22 (Gunshot Victim Revealed Digestion Science) – If you visit Mackinac Island, you can find a lot of history on these two. The doctor basically kept St. Martin as a slave, hunting him down when he tried to escape. He eventually got away, though, and ended up outliving the doctor by a good margin.
RE: Fact #1 (Misplaced and Fused Human Kidneys) – A friend who works as a surgical tech told me that one of the craziest parts of the job is how surgeons often have to hunt around to see where everything is located. When my dad had a major surgery, they shifted his organs around to help them heal better, and he ended up with what looks like a permanent beer belly from it. It makes you realize how much everything shifts, especially during pregnancy.
RE: Fact #50 (Smell Bypasses Brain Thalamus Filter) – I am usually pretty good at managing my PTSD triggers when it comes to things I see or touch. Sound is hit or miss for me. But smells hit me so fast before I even know what is happening. I have managed to get past some of them, but others are still really tough.
RE: Fact #32 (Ketones Fuel Brain During Starvation) – You can actually produce those without starving yourself, too, just by cutting out almost all carbs. A lot of people do it for weight loss because it essentially tricks your body into burning its own fat for fuel, just like fasting.
RE: Fact #48 (Choir Singing Synchronizes Heartbeats) – I am not sure about it being “unconscious” coordination. In every choir I have been in, the director specifically taught us to time our breathing for the breaks between lines. We were even told to stagger our breaths in large groups so we didn’t all inhale at once and ruin the sound. You can even see breath marks, like little apostrophes, on the sheet music telling you exactly when to do it.
RE: Fact #40 (Peanut Butter Test Detects Alzheimer’s) – This is a bit unsettling. I’m in my 80s and have lost most of my sense of smell; I only get faint hints of things that everyone else finds overwhelming. I’ve lost my sense of taste, too. Everything tastes the same unless it’s really spicy, which just registers as unpleasant. That’s why I keep going to McDonald’s; why pay for an expensive meal if it’s all going to taste the same anyway?
RE: Fact #6 (Bitter Drinks Boost Digestion) – The perfect way to ruin a romantic dinner: “I’ll be right there, honey, I’m just priming my body’s natural defenses to poison!”
RE: Fact #17 (Blind Man Navigates Without Sight) – Really interesting stuff. I work in neurology and we see this kind of thing all the time. Some patients develop a field cut, where they literally can’t see anything past a certain point. If you stand on their blind side, they won’t even realize you’re there because their brain isn’t processing that side of the world.
You really had to use the word see there, didn’t you?
RE: Fact #44 (Birth Method Shapes Baby Microbiome) – Does this actually change anything for the baby long-term? I wonder if there is a noticeable link to digestion issues or other health stuff.
RE: Fact #32 (Ketones Fuel Brain During Starvation) – It feels like every year around this time, we get a bunch of facts that line up with medical school curricula. I think we had a kidney transplant one yesterday too.
RE: Fact #39 (Kidneys Filter Blood Every Five Minutes) – That’s not quite right. It just means that within five minutes, your kidneys have processed a volume of blood equal to what you have. Some of it might have been processed a few times while other parts haven’t hit the kidneys yet.
RE: Fact #2 (Meat Fueled Human Brain Growth) – This is pretty controversial. Plus, why compare us to gorillas instead of chimpanzees? They are way closer to us genetically.
RE: Fact #7 (Diaphragm Singing Caused Vocal Damage) – It feels like this happens in all sports now. You’re expected to be at peak performance every single second or you’re done. If a singer like Adele isn’t hitting massive notes, people act like she should retire. It’s a sad, all-or-nothing mindset that just burns people out.
Welcome to the world of extreme competition. You either perform perfectly on command or get out.
RE: Fact #4 (Man With Donor DNA Body) – Bone marrow doesn’t actually create sperm. The person in this case had a vasectomy, so the donor DNA found in his semen came from other cells like lymphocytes and leukocytes. He can’t pass on donor genetics to his kids, but that won’t stop the clickbait headlines.
I thought something sounded off about that. My biology classes were a long time ago, but I’m fairly certain bone marrow is way too differentiated to produce sperm or eggs.
RE: Fact #24 (Dust Mites Cause Cleaning Sneezes) – I never realized sneezing was an allergic reaction. I just assumed it happened because I got some dust or foreign stuff stuck in my nose.