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8 Little Known Facts About the Temple

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The human body is an amazing thing. For each one of us, it’s the most intimate object we know. And yet most of us don’t know enough about it: its features, functions, quirks, and mysteries. Our series The Body explores human anatomy, part by part. Think of it as a mini digital encyclopedia with a dose of wow.

 

At the edges of the eyebrows, you’ll find the temple, the flat, tender side of the head where you often press your fingers to relieve a headache. In movies, one karate chop to this area can allegedly kill a person, but is this really true? What lies beneath that smooth surface of skin that’s so delicate? To learn more, Mental Floss spoke to Dr. Abbas Anwar, an otolaryngologist and head and neck surgeon at Southern California Head and Neck Medical Group in Santa Monica.

1. THE TEMPLE IS A JUNCTURE.

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It's technically where four skull bones—the frontal, parietal, temporal, and sphenoid—meet in the skull. This vulnerable juncture is called the pterion, which means "wing" in Greek but sounds like a kind of dinosaur.

2. IT REVEALS A DISTANT LINK TO REPTILES.

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The temporal bone itself is made up of five smaller parts, which fuse together before birth. One of these pieces, called the tympanic part, may be evolutionarily linked to the angular bone in the lower jaws of reptiles.

3. IT'S THE THINNEST PART OF THE SKULL …

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While these skull bones are "relatively strong," though thin, Anwar tells Mental Floss, the point at which they meet is the weakest point because there's no solid bone beneath them. "As such, this area is at risk with direct horizontal blows."

4. … WHICH IS WHY MAORI WARRIORS CRAFTED A SPECIAL WEAPON TO CRUSH IT.

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When Maori warriors of the first nations tribes of New Zealand and Australia went into battle, one weapon they took with them was the patu onewa, a flat, heavy club carved from stones such as basalt, and sometimes jade, for the specific purpose of delivering a fatal, crushing blow to the temple.

5. THE TEMPLE COVERS A MAJOR ARTERY.

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Running below these bones is a large artery known as the middle meningeal artery. It supplies blood to the outer covering of the brain, the meninges. "If hit hard enough, one of the four bones at this point can fracture inward and lacerate the middle meningeal artery," Anwar explains. This can cause an epidural hematoma, essentially "a collection of blood that builds up around the brain and compresses it."

Severe bleeding can cause "catastrophic consequences" if not recognized and treated promptly, including brain herniation (bulging brain tissue), hemiparesis (weakness of one side of the body), and death.

6. IS YOUR TEMPLE A SACRED SPACE?

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Etymologists don't entirely agree on the meaning of the word temple, which has multiple origins. It may derive from the Latin word for time, tempus, according to a Dartmouth Medical School anatomy course: "The connection may be that with the passage of time, grey hairs appear here early on. Or it may relate to the pulsations of the underlying superficial temporal artery, marking the time we have left here."

It could also possibly hail from the Greek word temenos, meaning "place cut off," which would explain the idea of a temple of worship as well as that juncture of bones at the side of the head. 

In Old English, tempel meant "any place regarded as occupied by divine presence," which might be code for the brain as the residence of consciousness or God.

More likely it's related to the Greek pterion, which as you'll recall means "wing." In Greek mythology, Hermes, messenger of the gods, wore a helmet with wings, which were positioned over the temples.  

7. IT'S PRONE TO SKIN CANCER THAT'S HARD TO REMOVE.

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Surgeon Gabriel Weston writes in The Guardian that skin cancers frequently turn up in this area from over exposure to the Sun, which makes for a challenging surgical procedure. "It is often not possible simply to sew up the hole in the skin after cutting a cancer out, since doing so can easily distort the contour of the eye," he writes.

To get around the problem, Weston uses a special technique called a Wolfe graft. After cutting away the cancerous lesion, "I measure out a circle of equal size in the skin above the collar-bone (where the skin is similar) and remove it." He grafts this skin patch to the patient's temple "with tiny silk sutures." 

8. BRAIN FREEZE ISN'T IN YOUR BRAIN.

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Sometimes when you eat or drink something cold too quickly, you get brain freeze, which can feel like someone has taken knives to your temples. But the pain isn't actually in your brain at all, as brains have no pain receptors. While researchers haven't been able to determine a cause of what's technically called sphenopalatine ganglioneuralgia, or sometimes HICS ("headache attributed to ingestion or inhalation of a cold stimulus"), they theorize that the painful freeze you experience is likely caused by a quick cooling of the blood in the back of your throat at the juncture your internal carotid and anterior cerebral arteries, which can cause spasms or constrictions of the arterial branches.

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12 Fantastic Facts About the Immune System
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The human body is an amazing thing. For each one of us, it's the most intimate object we know. And yet most of us don't know enough about it: its features, functions, quirks, and mysteries. Our series The Body explores human anatomy, part by part. Think of it as a mini digital encyclopedia with a dose of wow.

If it weren't for our immune system, none of us would live very long. Not only does the immune system protect us from external pathogens like viruses, bacteria, and parasites, it also battles cells that have mutated due to illnesses, like cancer, within the body.

Here are 12 fighting facts about the immune system.

1. THE IMMUNE SYSTEM SAVES LIVES.

The immune system is a complex network of tissues and organs that spreads throughout the entire body. In a nutshell, it works like this: A series of "sensors" within the system detects an intruding pathogen, like bacteria or a virus. Then the sensors signal other parts of the system to kill the pathogen and eliminate the infection.

"The immune system is being bombarded by all sorts of microbes all the time," Russell Vance, professor of immunology at University of California, Berkeley and an investigator for the Howard Hughes Medical Institute, tells Mental Floss. "Yet, even though we're not aware of it, it's saving our lives every day, and doing a remarkably good job of it."

2. BEFORE SCIENTISTS UNDERSTOOD THE IMMUNE SYSTEM, ILLNESS WAS CHALKED UP TO UNBALANCED HUMORS.

Long before physicians realized how invisible pathogens interacted with the body's system for fighting them off, doctors diagnosed all ills of the body and the mind according to the balance of "four humors": melancholic, phlegmatic, choleric, or sanguine. These criteria, devised by the Greek philosopher Hippocrates, were divided between the four elements, which were linked to bodily fluids (a.k.a. humors): earth (black bile), air (blood), water (phlegm) and fire (yellow bile), which also carried properties of cold, hot, moist, or dry. Through a combination of guesswork and observation, physicians would diagnose patients' humors and prescribe treatment that most likely did little to support the immune system's ability to resist infection.

3. TWO MEN WHO UNRAVELED THE IMMUNE SYSTEM'S FUNCTIONS WERE BITTER RIVALS.

Two scientists who discovered key functions of the immune system, Louis Pasteur and Robert Koch, should have been able to see their work as complementary, but they wound up rivals. Pasteur, a French microbiologist, was famous for his experiments demonstrating the mechanism of vaccines using weakened versions of the microbes. Koch, a German physician, established four essential conditions under which pathogenic bacteria can infect hosts, and used them to identify the Mycobacterium tuberculosis bacterium that causes tuberculosis. Though both helped establish the germ theory of disease—one of the foundations of modern medicine today—Pasteur and Koch's feud may have been aggravated by nationalism, a language barrier, criticisms of each other's work, and possibly a hint of jealousy.

4. SPECIALIZED BLOOD CELLS ARE YOUR IMMUNE SYSTEM'S GREATEST WEAPON.

The most powerful weapons in your immune system's arsenal are white blood cells, divided into two main types: lymphocytes, which create antigens for specific pathogens and kill them or escort them out of the body; and phagocytes, which ingest harmful bacteria. White blood cells not only attack foreign pathogens, but recognize these interlopers the next time they meet them and respond more quickly. Many of these immune cells are produced in your bone marrow but also in the spleen, lymph nodes, and thymus, and are stored in some of these tissues and other areas of the body. In the lymph nodes, which are located throughout your body but most noticeably in your armpits, throat, and groin, lymphatic fluid containing white blood cells flows through vein-like tubules to escort foreign invaders out.

5. THE SPLEEN HELPS YOUR IMMUNE SYSTEM WORK.

Though you can live without the spleen, an organ that lies between stomach and diaphragm, it's better to hang onto it for your immune function. According to Adriana Medina, a doctor who specializes in hematology and oncology at the Alvin and Lois Lapidus Cancer Institute at Sinai Hospital in Baltimore, your spleen is "one big lymph node" that makes new white blood cells, and cleans out old blood cells from the body.

It's also a place where immune cells congregate. "Because the immune cells are spread out through the body," Vance says, "eventually they need to communicate with each other." They do so in both the spleen and lymph nodes.

6. YOU HAVE IMMUNE CELLS IN ALL OF YOUR TISSUES.

While immune cells may congregate more in lymph nodes than elsewhere, "every tissue in your body has immune cells stationed in it or circulating through it, constantly roving for signs of attack," Vance explains. These cells also circulate through the blood. The reason for their widespread presence is that there are thousands of different pathogens that might infect us, from bacteria to viruses to parasites. "To eliminate each of those different kinds of threats requires specialized detectors," he says.

7. HOW FRIENDLY YOU'RE FEELING COULD BE LINKED TO YOUR IMMUNE SYSTEM.

From an evolutionary perspective, humans' high sociability may have less to do with our bigger brains, and more to do with our immune system's exposure to a greater number of bacteria and other pathogens.

Researchers at the University of Virginia School of Medicine have theorized that interferon gamma (IG), the immune cytokine that helps the immune system fight invaders, was linked to social behavior, which is one of the ways we become exposed to pathogens.

In mice, they found IG acted as a kind of brake to the brain's prefrontal cortex, essentially stopping aberrant hyperactivity that can cause negative changes in social behavior. When they blocked the IG molecule, the mice's prefrontal cortexes became hyperactive, resulting in less sociability. When they restored the function, the mice's brains returned to normal, as did their social behavior.

8. YOUR IMMUNE SYSTEM MIGHT RECRUIT UNLIKELY ORGANS—LIKE THE APPENDIX—INTO ITS SERVICE.

The appendix gets a bad rap as a vestigial organ that does nothing but occasionally go septic and create a need for immediate surgery. But the appendix may help keep your gut in good shape. According to Gabrielle Belz, professor of molecular immunology at the Walter and Eliza Hall Institute of Medical Research in Melbourne, Australia, research by Duke University's Randal Bollinger and Bill Parker suggests the appendix houses symbiotic bacteria that are important for overall gut health—especially after infections wipe out the gut's good microbes. Special immune cells known as innate lymphoid cells (ILCs) in the appendix may help to repopulate the gut with healthy bacteria and put the gut back on track to recovery.

9. GUT BACTERIA HAS BEEN SHOWN TO BOOST IMMUNE SYSTEMS IN MICE.

Researchers at the University of Chicago noticed that one group of mice in their lab had a stronger response to a cancer treatment than other mice. They eventually traced the reason to a strain of bacteria—Bifidobacterium—in the mice's guts that boosted the animals' immune system to such a degree they could compare it to anti-cancer drugs called checkpoint inhibitors, which keep the immune system from overreacting.

To test their theory, they transferred fecal matter from the robust mice to the stomachs of less immune-strengthened mice, with positive results: The treated mice mounted stronger immune responses and tumor growth slowed. When they compared the bacterial transfer effects with the effects of a checkpoint inhibitor drug, they found that the bacteria treatment was just as effective. The researchers believe that, with further study, the same effect could be seen in human cancer patients.

10. SCIENTISTS ARE TRYING TO HARNESS THE IMMUNE SYSTEM'S "PAC-MAN" CELLS TO TREAT CANCER.

Aggressive pediatric tumors are difficult to treat due to the toxicity of chemotherapy, but some researchers are hoping to develop effective treatments without the harmful side effects. Stanford researchers designed a study around a recently discovered molecule known as CD47, a protein expressed on the surface of all cells, and how it interacts with macrophages, white blood cells that kill abnormal cells. "Think of the macrophages as the Pac-Man of the immune system," Samuel Cheshier, lead study author and assistant professor of neurosurgery at Stanford Medicine, tells Mental Floss.

CD47 sends the immune system's macrophages a "don't eat me" signal. Cancer cells fool the immune system into not destroying them by secreting high amounts of CD47. When Cheshier and his team blocked the CD47 signals on cancer cells, the macrophages could identify the cancer cells and eat them, without toxic side effects to healthy cells. The treatment successfully shrank all five of the common pediatric tumors, without the nasty side effects of chemotherapy.

11. A NEW THERAPY FOR TYPE 1 DIABETES TRICKS THE IMMUNE SYSTEM.

In those with type 1 diabetes, the body attacks its own pancreatic cells, interrupting its normal ability to produce insulin in response to glucose. In a 2016 paper, researchers at MIT, in collaboration with Boston's Children's Hospital, successfully designed a new material that allows them to encapsulate and transplant healthy pancreatic "islet" cells into diabetic mice without triggering an immune response. Made from seaweed, the substance is benign enough that the body doesn't react to it, and porous enough to allow the islet cells to be placed in the abdomen of mice, where they restore the pancreatic function. Senior author Daniel Anderson, an associate professor at MIT, said in a statement that this approach "has the potential to provide [human] diabetics with a new pancreas that is protected from the immune system, which would allow them to control their blood sugar without taking drugs. That's the dream."

12. IMMUNOTHERAPY IS ON THE CUTTING EDGE OF IMMUNE SYSTEM RESEARCH.

Over the last few years, research in the field of immunology has focused on developing cancer treatments using immunotherapy. This method engineers the patient's own normal cells to attack the cancer cells. Vance says the technique could be used for many more conditions. "I feel like that could be just the tip of the iceberg," he says. "If we can understand better what the cancer and immunotherapy is showing, maybe we can go in there and manipulate the immune responses and get good outcomes for other diseases, too."

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Why Is Your First Instinct After Hurting Your Finger to Put It in Your Mouth?
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If you close your fingers in a car door or slam your funny bone into a wall, you might find your first reaction is to suck on your fingers or rub your elbow. Not only is this an instinctive self-soothing behavior, it's a pretty effective technique for temporarily calming pain signals to the brain.

But how and why does it work? To understand, you need to know about the dominant theory of how pain is communicated in the body.

In the 17th century, French scientist and philosopher René Descartes proposed that there were specific pain receptors in the body that "rang a bell in the brain" when a stimulus interacted with the body, Lorne Mendell, a professor of neurobiology and behavior at Stony Brook University in New York, tells Mental Floss. However, no study has effectively been able to identify receptors anywhere in the body that only respond to painful stimuli.

"You can activate certain nerve fibers that can lead to pain, but under other circumstances, they don't," Mendell says. In other words, the same nerve fibers that carry pain signals also carry other sensations.

In 1965, two researchers at MIT, Patrick Wall and Ronald Melzack, proposed what they called the gate control theory of pain, which, for the most part, holds up to this day. Mendell, whose research focuses on the neurobiology of pain and who worked with both men on their pain studies, explains that their research showed that feeling pain is more about a balance of stimuli on the different types of nerve fibers.

"The idea was that certain fibers that increased the input were ones that opened the gate, and the ones that reduced the input closed the gate," Mendell says. "So you have this idea of a gate control sitting across the entrance of the spinal cord, and that could either be open and produce pain, or the gate could be shut and reduce pain."

The gate control theory was fleshed out in 1996 when neurophysiologist Edward Perl discovered that cells contain nociceptors, which are neurons that signal the presence of tissue-damaging stimuli or the existence of tissue damage.

Of the two main types of nerve fibers—large and small—the large fibers carry non-nociceptive information (no pain), while small fibers transmit nociceptive information (pain).

Mendell explains that in studies where electric stimulation is applied to nerves, as the current is raised, the first fibers to be stimulated are the largest ones. As the intensity of the stimulus increases, smaller and smaller fibers get recruited in. "When you do this in a patient at low intensity, the patient will recognize the stimulus, but it will not be painful," he says. "But when you increase the intensity of the stimulus, eventually you reach threshold where suddenly the patient will say, 'This is painful.'"

Thus, "the idea was that shutting the gate was something that the large fibers produced, and opening the gate was something that the small fibers produced."

Now back to your pain. When you suck on a jammed finger or rub a banged shin, you're stimulating the large fibers with "counter irritation," Mendell says. The effect is "a decrease in the message, or the magnitude of the barrage of signals being driven across the incoming fiber activation. You basically shut the gate. That is what reduces pain."

This concept has created "a big industry" around treating pain with mild electrical stimulation, Mendell says, with the goal of stimulating those large fibers in the hopes they will shut the gate on the pain signals from the small fibers.

While counter irritation may not help dull the pain of serious injury, it may come in handy the next time you experience a bad bruise or a stubbed toe.

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