 “Anatomy is destiny,” Sigmund Freud once said. Then again, Siggy also opined that “time spent with cats is never wasted,” so perhaps he should’ve stuck to pondering the psychosexual ramifications of kielbasa. Nevertheless, he was onto something: The human body is a marvel yet to be equaled in nature or a Japanese robotics lab. Your 206 bones, 600 muscles, 100,000 miles of blood vessels, and assorted innards—all laboring in harmony—enable you to pursue the full spectrum of human endeavor. Of course, the typical guy treats his body like a rental car, filling it with garbage and dinging the chassis with no regard for what lies down the road. Luckily, your vessel is more resilient than a Taurus. The damage inflicted by most of your bad habits starts healing the moment you put down that bacon, rum, and tobacco sandwich. Since the dawn of the human race, we’ve been studying the mystery of our bodies, and in the past few years scientists have made incredible discoveries that help us further understand who we are. To quote another great thinker, your body is a machine, a chemical laboratory, a powerhouse. So get ready—we’re going in.
 The Heart
It weighs less than a pound and thumps 100,000 times a day.
Lowdown: About the size of a clenched fist and located in the center of your chest—not on the left side—your heart has four chambers made of muscle that form a squishy pump. It beats about 100,000 times and processes 2,000 gallons of blood daily. “The heart makes the Energizer Bunny look like a wimp,” says Dr. Clyde W. Yancy, chief of the cardiothoracic transplantation program at Baylor University Medical Center. “It goes on and on.” Unless, that is, you treat it like a garbage disposal. “I’ve opened up blood vessels that look like congealed cheese,” says Dr. Yancy. “I haven’t eaten pizza in 15 years.”
Destress for success: Scientific big-brains have yet to figure out the exact connection between stress and heart disease, but research indicates that the surge in adrenaline produced by stress causes the blood to clot more readily. On a behavioral level, mortgage payments and work deadlines tend to make us scarf cheesesteaks and skip Tae Bo class. “If you’re a 30-year-old male and you don’t have stress, either you’re a bum or independently wealthy,” diagnoses Dr. Yancy. “And if you hang on to stress, it will end up becoming a physical issue.” So go for a swim or jog through a grizzly den while smeared with honey—whatever helps you blow off steam.
Cutting edge: Stem cells, those multipurpose little miracle organisms that scare President Bush more than a whole library of books, may be coming to a heart attack near you. Doctors intend to direct stem cell therapy to damaged areas of a diseased heart at the time of bypass surgery in hope of revitalizing tissue and improving overall heart function, says Dr. Yancy: “We could very well prevent the development of heart failure, or 10 to 15 years from now, actually reverse the effects of a heart attack.” We’ve got an even bolder idea—inject stem cells directly into cheeseburgers! Bonus: New research on intuition demonstrates that the heart may keep us alive in more ways than one. When subjects were shown random images, their heart rates increased five to seven seconds before seeing an emotionally charged image such as a car crash or a coiled snake. Researchers propose that the heart’s central role in “intuitive perception” may influence decision making in everything from defensive driving to high-stakes business meetings. In other words, yes, you have ESP.
 The Brain
All you need to know about man’s second-favorite organ.
Lowdown: Inside your quarter-inch-thick skull, wrapped in three layers of gooey membranes, your brain weighs in at about three pounds—roughly the same as a bottle of scotch. Made of soft, squeezable flesh deepred in color, the human brain contains more than 100 billion neurons, cells that process and transmit information back and forth. Not only is the organ the center of information processing and consciousness, but it also controls body temperature, pulse rate, and sex drive.
Cutting edge: New studies are solving the most intriguing human mysteries—how we feel love, what happens when we sleep, even the design of bionic limbs that’ll be controlled by thought. In the hunt to cure diseases and injuries, scientists are focused on neurogenesis, the brain’s ability to grow new neurons. But some of the most interesting research has nothing to do with our well-being. Take the dorsal striatum. Located in the center of the brain, it’s responsible for cravings. Research at the Brookhaven National Laboratory has proved that if it’s stimulated, cravings can occur when you’re not hungry. Thus the fetishized adverts for Taco Bell’s Cheesy Gordita Crunch, where hot sauce seems to ooze out of your TV screen. Those ads are designed to stimulate the same part of the brain that’s responsible for cocaine cravings in addicts.
Turbocharge your brain: No operation or syringeful will turbocharge your noggin better than a regimen of physical exercise. “Studies in both animals and humans show that exercise leads to a lot of changes in the brain: increase in blood flow, regulation of chemicals associated with brain plasticity—our ability to learn—and neurogenesis,” says Dr. Yaakov Stern, who heads the Cognitive Neuroscience Division at Columbia University Medical Center.
This is your brain on… Booze really does kill brain cells. “The threshold for neurotoxicity with alcohol is about one ounce a day,” says Dr. Kenneth Heilman of the University of Florida. While social drinkers rarely show signs of permanent neuronal damage, studies in rats have found that binge drinking in adolescence leads to memory loss in adulthood.
Frontal lobe: The largest section of the brain is responsible for voluntary movement, reasoning, and problem solving. It enables you to give someone the finger, tally the tip on a lunch check, and a host of other quotidian activities.
Prefrontal lobe: Controls judgment and inhibition. Bruise this part of the brain and you’ll be banging homeless chicks sans condom and betting your savings account on a craps game.
Hippocampus: Found in the medial temporal lobe, the hippocampus plays a critical role in long-term episodic memory, recalling experiences from your past. The memory of your first screw lives here. So does the memory of your first premature ejaculation.
Amygdala: Found in the frontal lobe, the amygdala tastes like chicken. Or so we’re told. It’s responsible for emotions such as terror and joy. Ever been so scared you wet your pants? That’s your amygdala at work.
Hypothalamus: Located just above the brain stem, this almond-size region controls all of the body’s metabolic processes. In other words, it’s the annoying voice in your head that says, “I’m
cold,” “I’m hungry,” “I’m thirsty”…
Temporal lobe: Critical for expressive speech, it commands the mouth to form sentences. Also plays a major role in memory retrieval. This is where all the lyrics from the Beatles’ White Album are archived.
Parietal lobe: A key center for sensory processing and body orientation. Say you’re in a bar and some dude throws a punch. While the frontal lobe says, “Get the screw out of the way!” the parietal lobe enables you to see where the punch is going and duck it.
Occipital lobe: This is where most visual input is processed and interpreted, enabling you, for example, to comprehend what you’re reading right now. It’s also the portal into your visual perception.
 The Blood
At all costs, keep this stuff on the inside of your body.
Lowdown: Since the beginning of recorded time, humans have worshiped blood—drunk it, painted with it, named their gangs after it. Technically, blood is a tissue, like muscle or skin. You have 5.6 liters of it pumping through roughly 100,000 miles of arteries, veins, and capillaries. Think of red blood cells, the key ingredient, as 18-wheelers moving around the superhighways and roads within your body, carrying oxygen and nutrients where they’re needed and carting away the garbage. Your network of blood vessels also functions as a liquid cooling system that keeps your organs from stewing in their own juices.
How much can you lose without dying? Estimates vary. The Nazis reportedly did experiments, results unknown. “Generally, if you’re athletic and healthy, you could lose maybe 40 percent of your blood and live, as long as you got a transfusion fairly quickly,” says James Louie, M.D., a VP at the New York Blood Center. By the way, red blood cells have a lifespan of about four months, meaning your entire supply turns over three times a year. The dead cells head for the spleen, your heart’s recycling dump.
Supercharge your blood: Blood doping is the process of adding more oxygen-carrying agents to the bloodstream through the injection of synthetic hormones (such as EPO) or blood transfusion. This practice can deliver up to a five-percent boost in your body’s athletic capabilities, says Michael Ashenden, who heads the Science and Industry Against Blood Doping consortium. “Compared with the one-percent improvement an elite athlete might hope for during an entire training season and the half-percent difference between winning and losing,” he adds, “it’s easy to recognize the enormous temptation to cheat, especially when the chance of being caught is minimal.”
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