If the Heart Is a Muscle, Why Doesn’t It Get Tired?

iStock/magicmine
iStock/magicmine

You’re on the weight bench. 18. 19. 20! You couldn’t lift that barbell again if someone had a gun to your head. Your arms and your chest are sizzling with a dull burn. Your muscles are fatigued, and as you try to put the bar back, your arms give out.

Then there's a crash.

Dropping a barbell on yourself is one thing, but imagine if your heart just up and stopped whenever it got tired of beating. It would be disastrous and defibrillator makers would rule the world. We, and every other thing with a heart, would be extinct in no time.

Unlike the rest of your muscles, your heart expands and contracts, non-stop, all day and all night for your entire life without a break. How does it do it?

Your heart might be a muscle, but it isn’t quite like your biceps or your abs or your pecs. Those are all “skeletal muscles” and they’re attached to your bones. Your heart, meanwhile, is made of “cardiac muscle.”

Both of these types of muscles need energy to contract, and they both get it from mitochondria, the so-called “cellular power plants" that generate adenosine triphosphate (ATP) for the transfer of chemical energy. Cardiac muscle resists fatigue so well because it’s got more mitochondria than skeletal muscle. With so many power plants at its disposal, the heart doesn’t need to stop and chill out. It also has a steady supply of blood bringing it oxygen and nutrients.

The Unkindest Cut: The Chainsaw Was Invented to Assist With Difficult Childbirths

viafilms/iStock via Getty Images
viafilms/iStock via Getty Images

There’s always a price to be paid for innovation. Usually that amounts to some sleepless nights and lots of trial and error. But sometimes it means attempting to deliver babies with a chainsaw.

This dark chapter in agricultural history comes from Popular Science, which recently detailed how the motorized cutting tool populating Home Depot shelves came to be. In the 18th century, two Scottish surgeons named John Aitken and James Jeffray devised a solution they could employ when faced with difficult childbirths. Rather than use a knife to widen the pelvic area by slicing through cartilage and bone to extricate a stuck baby, the two developed a chainsaw to make cutting easier.

While this sounds ghastly, the doctors were actually trying to lessen the agony endured by women who needed their pelvic bone separated. The knife took a long time, while their device—a modified knife with serrated “teeth” on a chain—could cut through bone and tissue more quickly.

If circumstances warranted it, the doctor would grab the saw, which had a handle on both ends, and wrap the chain around the pelvic bone, pulling each handle so the chain would cut into the bone. Later, the device was outfitted with a hand crank. Thanks to this innovation, difficult births could be described as merely agonizing as opposed to extended torture.

The procedure was dubbed a symphysiotomy and remained in use in the medical field as surgeons noticed how efficiently it could work in other circumstances, like amputations. It lasted through much of the 19th century as part of a surgical toolbox until C-sections grew in popularity. In the 20th century, the principle was commandeered for less disturbing purposes like logging, with two-person saws weighing more than 100 pounds each. By the 1950s, those gave way to lighter models.

For all its discomfiting history, at least the chainsaw proved to be useful—which isn't something that can be said for all inventions purporting to aid in childbirth. In 1965, George and Charlotte Blonsky patented a device that acted as a human turntable, spinning so quickly it might induce the patient (or victim) into delivering their baby via centrifugal force.

[h/t Popular Science]

Kane Tanaka, World’s Oldest Living Person, Just Celebrated Her 117th Birthday

Ruletka, iStock via Getty Images
Ruletka, iStock via Getty Images

Less than a year after being named oldest living person in the world, Kane Tanaka has reached a new milestone. As Reuters reports, Tanaka celebrated her 117th birthday on January 2, 2020, extending the Guinness World Record-winning streak she set in March 2019.

Kane—the seventh of eight siblings—was born on January 2, 1903 in Fukuoka, Japan. She married Hideo Tanaka in 1922, and the couple had five children. Today, she is a grandmother to five and a great-grandmother to eight.

Tanaka celebrated her birthday at the Fukuoka nursing home where she resides, surrounded by friends and family. After taking a bite of her birthday cake, she reportedly said, “Tasty, I want some more." On a typical day, Tanaka spends her time studying math, practicing calligraphy, and beating the nursing home staff at board games.

The 117 club is an exclusive group only a handful of women has entered in recent history. In the last few years, Emma Morano of Italy, Violet Mosse Brown of Jamaica, and Nabi Tajima and Chiyo Miyako of Japan all reached age 117 and were each the oldest person alive for a brief period. If Tanaka celebrates another birthday next year, she will be the first person since the 1990s to live to 118.

[h/t Reuters]

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