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1,016 cards. Each one is a 40-second story with a five-minute read behind it. Page 10 of 17.

  1. Brain swelling is deadly because the skull has no room to spareMost swollen tissue can simply expand. The brain cannot, because the skull is a rigid box. When fluid builds up inside it, something else has to give, so blood vessels, spinal flu…
  2. Chest pain in adults is more often the gut than the heartChest pain sends about 8 million Americans to emergency departments every year, costing more than $8 billion. Heart disease is behind roughly 31% of adult cases, but digestive pro…
  3. Modern chewing gum began as a failed Mexican substitute for rubberIn the 1860s the exiled Mexican general Antonio López de Santa Anna brought chicle, a tree gum, to New York and handed it to Thomas Adams to try as a rubber substitute. As rubber …
  4. Chiropractic's founder said he learned it from a long-dead doctorD. D. Palmer, a spiritualist, founded chiropractic in the 1890s and claimed the method came to him from the other world, passed on by a physician who had died 50 years earlier. Th…
  5. The first antipsychotic drug is still on the WHO essential medicines listChlorpromazine, developed in 1950 and sold as Thorazine and Largactil, was the first antipsychotic to reach the market, and its arrival is counted among psychiatry's great advance…
  6. Carpal tunnel syndrome may be written into your wrists at birthCarpal tunnel syndrome is often blamed on typing or repetitive work, and those strains do count as risk factors. But genes appear to be the biggest factor: one large genetic study…
  7. Adrenaline, noradrenaline and dopamine are built on one production lineYour fight-or-flight chemicals are siblings made in sequence. Cells turn the amino acid tyrosine into L-DOPA, then dopamine; add one enzyme and dopamine becomes noradrenaline, add…
  8. Textbooks once said carbonic acid couldn't exist on its own. They were wrongFor much of the twentieth century chemists believed carbonic acid lived only fleetingly in solution. Pure, it turns out to be surprisingly durable; it is water that tears it apart…
  9. Business Insider began as a blog about Manhattan's tech sceneBusiness Insider started in 2007 as Silicon Alley Insider, a single blog about New York's tech scene. Within eight years a German publisher paid $343 million for most of it. Along…
  10. A missing safety interlock on a North Sea rig rewrote diving rulesIn November 1983, a clamp on the Byford Dolphin drilling rig opened while its diving chambers were still pressurised at nine atmospheres. Five men died in an instant. Norway made …
  11. Camphor flavoured Tang ice cream, made early plastics and sparked a bombardmentA waxy crystal distilled from Asian laurel wood, camphor has perfumed Arab courts, flavoured one of the earliest recorded ice creams, embalmed Egyptian mummies and served as the k…
  12. The curved bacterium hiding on nearly half of packaged Canadian chickenCampylobacter is one of the world's commonest bacterial causes of stomach upsets, and raw or undercooked poultry is a major route in. Canadian testing found it on nearly half of p…
  13. Better scans can make cancer survival statistics improve without anyone living longerDoctors grade how far a cancer has spread from stage I, a tumour confined to one spot, to stage IV, where it has reached distant organs. That number steers treatment. But when sca…
  14. Chilli heat is a weapon aimed at mammals that birds cannot feelCapsaicin, the molecule behind chilli burn, grips a pain receptor that mammals have and birds effectively lack. That suits the plant perfectly: birds swallow the seeds whole and s…
  15. Bell peppers and fiery chiltepins belong to one and the same speciesA sweet bell pepper scores zero on the Scoville scale; a wild chiltepin can reach 200,000. Both are Capsicum annuum, a plant Mesoamerican farmers domesticated about 6,000 years ag…
  16. Women in one study ranked a partner's smell above his looksAsked what mattered for attraction, women in one study put body odour ahead of appearance. A leading explanation lies in immune genes: people often prefer the scent of partners wh…
  17. Your bone marrow makes about 500 billion blood cells every dayTucked inside spongy bone, marrow makes up roughly 5% of an adult's body mass, around 3.7 kg in a 73 kg person. It turns out some 500 billion blood cells a day. A newborn's bones …
  18. Every movement of your arm runs through one tangled nerve junctionFive nerve roots leave the spine at the base of the neck, merge, split and merge again before reaching the arm. This braid, the brachial plexus, wires almost every muscle and patc…
  19. Your brain moves by releasing a brake, not by pressing an acceleratorDeep in the forebrain, the basal ganglia keep the body's motor systems under constant restraint. Their output neurons fire steadily at high rates, suppressing movement, and an act…
  20. Blue-and-yellow macaws blush when they interact with peopleThe blue-and-yellow macaw can flush the bare white skin of its face and fluff its cheek feathers while dealing with humans, possibly a sign of its mood. It is the most commonly ke…
  21. Sweat barely smells; armpit bacteria turn it into body odourFresh sweat is not what you smell. Apocrine glands, which switch on at puberty, release compounds that skin bacteria digest into pungent molecules. Different microbes dominate in …
  22. Kolkata's Great Banyan is one tree standing on 2,880 extra trunksA banyan often starts life high in another tree, dropping roots to the ground that thicken into trunks. Given time it can smother its host and keep spreading sideways indefinitely…
  23. Barbed wire began with a county-fair display and a coffee millAt a DeKalb, Illinois, fair in 1873, a farmer named Joseph Glidden saw a wooden strip studded with metal points meant to stop cows. He went home, made barbs with his coffee mill, …
  24. How a false death report split an ancient Christian church in twoIn 1553 Roman officials were told, wrongly, that the elderly patriarch of the Church of the East had died. The pope appointed a rival, Yohannan Sulaqa, and centuries of competing …
  25. Star-shaped brain cells once dismissed as packing turn out to talk backAstrocytes, named for their star shape, were long seen as scaffolding for neurons. Since the mid-1990s researchers have watched them pass calcium waves across long distances and r…
  26. Every meal you eat started with an organism that feeds on light or rockAutotrophs build their own food out of carbon dioxide, powered by sunlight or by chemical reactions with minerals. Plants, algae and vent-dwelling microbes sit at the base of ever…
  27. You can be aware without being awake, and awake without being awareAwareness feels like the simplest fact of life, yet scientists and philosophers still argue over what it is. Dreamers are aware while asleep, some brain-damaged patients seem awak…
  28. Every land plant descends from a cell that swallowed a cyanobacteriumGreen algae, red seaweeds, tiny grey algae and every tree and flower belong to one proposed lineage, the Archaeplastida, meaning ancient plastid. Its founding ancestor engulfed a …
  29. Why aspartame keeps getting cleared and questioned at the same timeAspartame is roughly 200 times sweeter than table sugar, so a pinch replaces a spoonful and adds almost no energy. Over 100 regulators have judged it safe within set limits. Yet i…
  30. A priest named this mold after a holy water sprinklerPeering through a microscope in 1729, the Italian priest Pier Antonio Micheli saw spore heads shaped like the aspergillum used to scatter holy water, and named the genus Aspergill…
  31. The black mold on your onions also makes most of the world's citric acidThe sooty fungus that spoils grapes, apricots and peanuts is also a factory workhorse. Fed sugar in acidic tanks, Aspergillus niger turns out more than a million metric tons of ci…
  32. Your two amygdalae keep separate memories and may handle emotions differentlyDeep in each temporal lobe sits an almond-shaped cluster of thirteen nuclei that tags experiences with fear, pleasure and meaning. Electrically stimulating the right one tends to …
  33. Under polarised light, the proteins behind amyloidosis glow apple-greenAmyloidosis happens when proteins fold the wrong way, stack into rigid fibres and pile up in organs the body cannot clean. Its early signs are vague, like tiredness, swollen ankle…
  34. Why doctors say biceps brachii: anatomy's dead languages exist to stop mistakesTell someone you have a scar above the wrist and they might picture your forearm or the heel of your palm. Anatomists avoid that ambiguity with a vocabulary drawn from Greek and L…
  35. On a horse, front and back become cranial and caudal, because anatomy depends on postureIs your back posterior or dorsal? For a human it is both, but on a dog those words point in different directions. Anatomists anchor every direction to a fixed reference pose, and …
  36. An aortic aneurysm is usually silent until it bursts, which is why screening mattersThe body's largest artery can quietly balloon to over one and a half times its normal width without causing a single symptom. The first sign is often a rupture, with sudden agonis…
  37. Aragonite shouldn't exist at Earth's surface, yet it builds almost every seashellChemically, aragonite is just calcium carbonate, the same stuff as chalky calcite. Physically it is the version that ought to form only under crushing pressure. Yet corals and nea…
  38. Kevlar and Nomex differ by where one chemical link sits on a carbon ringThe fibre in bulletproof vests and the fabric in firefighters' suits are close chemical cousins. Both are aramids, chains of six-carbon rings joined by amide links. Attach those l…
  39. The strawberry tree flowers and ripens last year's fruit at the same timeIts red berries look like strawberries but the tree belongs to the heather family. Arbutus unedo takes about a year to ripen each crop, so every autumn it carries white bell flowe…
  40. Elephants are closer kin to golden moles than to rhinos or hipposElephants, manatees, aardvarks, hyraxes and tiny golden moles look nothing alike, yet they share one family tree. Nobody recognised it until DNA studies in 1998. The group, Afroth…
  41. A scientist's wife suggested the seaweed jelly that transformed microbiologyIn 1882 Walther Hesse, working in Robert Koch's lab, needed a better surface for growing bacteria. His wife Fanny suggested agar, a jelly made from seaweed and long used in Asian …
  42. Agnosia lets you see a face perfectly and still not know who it isPeople with agnosia have working eyes, ears or noses and intact memories, yet the brain fails to turn the signal into recognition. One patient, asked about breakfast, said the wor…
  43. A swelling in the body's main artery usually gives no warning before it burstsAn abdominal aortic aneurysm is a bulge in the aorta below the chest, wider than 3 cm. Most cause no symptoms at all until they rupture, and a rupture kills 85 to 90 per cent of p…
  44. The pretty red rosary pea hides a toxin deadlier than ricinRosary pea seeds, glossy scarlet with a black spot like a ladybird, are strung into bracelets and rosaries. They also contain abrin, lethal at roughly one seventy-fifth the dose o…
  45. Every voluntary movement you make starts with one small chemical messengerWhenever you lift a finger, motor neurons squirt acetylcholine onto your muscle fibres, opening channels that let sodium rush in and trigger contraction. The same molecule helps w…
  46. Your Achilles tendon may be the reason humans can run at allThe thickest tendon in your body takes loads of 7.7 times your body weight with every running stride and stores that energy like a spring. Computer models suggest it lifts top run…
  47. One anonymous author wrote over a quarter of the New TestamentThe Gospel of Luke and the Acts of the Apostles are two halves of one work, and together they make up 27.5 per cent of the New Testament, more than any other single writer. The au…
  48. Whiskers are touch antennas evolution bolted onto mammal facesVibrissae—whiskers—are specialized sensory hairs that let most mammals detect air currents and objects for navigation, hunting, and spatial sense. They cluster above eyes, on chin…
  49. White cells live in the buffy coat between reds and plasmaLeukocytes—white blood cells—defend against infection and foreign matter, generally larger than red cells, in three main groups: granulocytes, lymphocytes, and monocytes. All aris…
  50. Seeing is the brain inventing a world from bouncing lightVisual perception is the knack of detecting light and building an image of the surroundings—more than bare light sensing. In most vertebrates it runs in photopic daytime and scoto…
  51. Your visual system is a layered machine that predicts motionThe visual system is the physiology behind visual perception: it detects, transduces, and interprets visible light to build images and a mental model of space. Tied to the eye and…
  52. Leaf mouths trade carbon dioxide for precious waterA stoma is an epidermal pore edged by two guard cells that meter gas exchange in most land-plant sporophytes—liverworts excepted. Daylight carbon dioxide at about 425 ppm enters w…
  53. Your stomach is a stretchy acid mill between gullet and gutThe stomach sits in the left upper abdomen as a hollow muscular bag between esophagus and duodenum. After the cephalic phase of smell and chewing, its gastric phase uses acid and …
  54. Five basic tastes are only the opening act of flavourTaste begins when chemicals meet receptor cells in buds clustered on tongue papillae—and also on palate, cheeks, and throat. Humans host roughly two to five thousand buds, each pa…
  55. Tendons are living ropes that turn muscle pull into bone motionA tendon is dense fibrous connective tissue linking muscle to bone, transmitting contraction while enduring tension. Ligaments join bone to bone; both rely on collagen, yet adults…
  56. Testes make sperm and testosterone inside a cooled scrotal pouchA testis is the male gonad, homologous to the ovary, charged with producing sperm and secreting androgens—chiefly testosterone. Two similar glands hang in the scrotum, an abdomina…
  57. The thorax is a bony cage that keeps heart and lungs workingBetween neck and abdomen, the thorax—named from a Greek word for breastplate—houses heart, lungs, and thymus behind a rib cage braced by spine and shoulder girdle. In arthropods t…
  58. A butterfly gland in the neck meters metabolism with iodineThe thyroid is a vertebrate endocrine organ that in humans forms a butterfly or H below the Adam's apple. Two lobes join by an isthmus; follicles lined by thyrocytes store colloid…
  59. Tissue is the woven middle layer between cell and organIn biology, tissue means similar cells plus their shared extracellular matrix, born from the same embryonic stock and cooperating on one job. Organs are coalitions of tissues; the…
  60. The tongue is a boneless hydrostat that tastes and talksIn tetrapods the tongue manipulates food, hosts taste buds on its dorsum, cleans teeth, and—in humans—shapes speech. Average length from oropharynx to tip is about ten centimetres…

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