Friday, October 25, 2013

A Bloody History

Halloween is upon us. The sweltering summer is slowly waning, the humidity is inching downward, and the first hint of cooler weather is creeping in. Those annoying little creatures (children) have returned to school, football and hockey are underway (finally!), and pumpkins are popping up all around town.
So to usher in the spooky season and to get everyone in the mood, we’re going to explore the history of one of our most essential bodily fluids. Join me as we take a bloody journey through time…

Long before human dissection was an accepted practice, the inner workings of the body were a mystery. Can you imagine the perplexity of our ancients as they sustained bloody injuries, yet had no idea what that red fluid was, how it was made, or what purpose it served within the body? It’s no wonder they ascribed spiritual and magical explanations to bodily functions…

Although the Egyptians didn’t understand blood’s basis, they, like many throughout history, thought the secret to curing illness was to bleed the patient. The practice of bloodletting persisted for over four thousand years and was believed to rid the body of impurities. It was also believed to restore balance of the “humors,” the four elements, according to Hippocrates, that made up the body: blood, phlegm (a personal favorite), and black and yellow bile. Our first president’s death was hastened, thanks to this ancient treatment.

It wasn’t until the dissections of Galen almost two thousand years after the Egyptians that we began to understand the body's plumbing (although he worked solely on apes). Galen recognized the fact that arteries and veins carried blood and that the blood circulated via vessels. But he mistakenly believed blood formed in the liver and passed from one side of the heart to the other. Hey, you can’t win 'em all.
By the 1500s, scientists and physicians concurred that the heart was involved in circulation (video!), although the exact mechanism still escaped them. Spaniard Michael Servetus refuted Galen’s theory about the flow of blood through the heart and, although he was correct about circulation, he was later burned at the stake for criticizing the Holy Trinity. 

In 1628, the British physician William Harvey correctly explained the role of the beating heart in his oh-so-popular text, Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus. A real page-turner…
Thirty years later, the up-and-coming Dutchman, Jan Swammerdam, (only twenty-one at the time!) was the first to describe red blood cells. I consider his discovery one of the truly missed nomenclature opportunities in science. Think how much more colorful biology would be if our circulatory system relied on "swammerdams" to oxygenate the body!

By the late 1600s, the concept of blood transfusion was still a work in progress. The first to attempt it was Parisian Jean-Baptiste Denis, and the experiments soon spread to England. Unfortunately, they chose to transfuse their patients with the blood of animals and after multiple failed attempts, the practice was kicked to the curb where it languished for almost 150 years. Finally, by the mid-1800s, docs had worked out the kinks, mainly by sticking to species-specific blood. They found human-to-human worked best, although even transfusions between peeps had problems. Sometimes the blood would clump, and it wasn’t until blood groups were identified that the mystery was finally solved.
In 1901, Karl Landsteiner identified three different types of blood: A, B, and O, and received a Nobel Prize for his efforts. A year later, Decastello and Sturli added a fourth type - AB, and the modern era of hematology was underway.

Today, we know an awful lot about blood. It is comprised of several crucial components. Red cells contain a protein called hemoglobin, which binds with oxygen, enabling blood to transport that essential gas throughout the body. White cells fight off infection, platelets form lifesaving clots, and plasma is the fluid in which the other components are suspended. Together, these constituents make up one of the most important fluids in the body.
The average adult contains about five liters. Blood is oxygenated in the lungs, pumped out by the heart, and circulated via the arteries. Veins return the oxygen-depleted blood to the heart, where it is then pumped back into the lungs, returned to the heart, and the cycle starts all over again (although within the pulmonary circulation, the roles of the veins and arteries are reversed). 

So as Halloween draws near, take a moment to appreciate the blood coursing through your veins. Place your finger against your carotid artery and relish the beautiful beat of your heart, knowing that with every pulse, every throb, that life-sustaining liquid is delivering its fragile cargo to your hungry tissues. I’ll leave you with the lovely words of Georg Büchner:

            The death clock is ticking slowly in our breast, and each drop of blood measures its time...”

Here's a great read on the history of transfusion:


Friday, October 18, 2013

Something smells...

Close your eyes and breathe deeply through your nose. What do you smell? Depending on where you are while you’re reading this, the range of odors may be vast. Sitting in your office? Perhaps you smell the ink from the copy machine or a pot of coffee brewing down the hall. At home, as I am at this moment? Perhaps you smell fresh laundry tumbling in the dryer or the wonderful attic smell of an old house. If you’re sitting on the john, we’d rather not know what you’re smelling at the moment.
Smell is one of our most important senses, although we rarely give it much thought. When I lived in London, my morning commute on the underground was a banquet of human odors. The diversity of people on the subway meant a broad swath of scents: spices, fragrances, and body odor. A veritable smorgasbord of aromas.

For firefighters, smell is part of the toolkit. Ask any firefighter and I bet they can describe the acrid odor of car fires, the earthy scent of a brushfire, or the stomach churning stench of burnt flesh. The smell of the smoke at times can indicate precisely what’s burning.
So today, in honor of our snouts, I’m paying homage to this vital link to the world around us.

First, let’s discuss the nuts and bolts of smell. Our noses serve as conduits for odor molecules that are drawn into our bodies as we inhale. Those odor molecules attach to chemoreceptors that line our noses, which, when stimulated, send signals to our brains. The brain then interprets these signals and voilà! A smell!
Humans can distinguish over ten thousand different odors. Amazing! Also amazing is that each of the hundreds of receptors lining the nose is controlled by a single gene! If you’re missing that gene, you miss out on that particular odor.

The olfactory bulb – that part of the brain that transforms smell sensation into perception – is part of the limbic system, a primitive region of the brain that regulates behaviors related to survival. Even in our distant reptilian relatives, the alligators, the limbic system processes smell, which allows gators to successfully hunt and defend their territory.
But it’s the amygdala and hippocampus, the parts of our limbic system responsible for emotion and memory, that draw the connection between smell and memory. The olfactory nerves run in close proximity to these vital areas, thus providing associated links between smells and the memories they trigger.

As our species evolved, our sense of smell would have played a crucial role in survival. Finding food and avoiding danger are two of our most fundamental behaviors that rely on smell. The smell of fresh dung can mean meat on the hoof. The smell of a rotting carcass can indicate predators nearby. Our ancestors were keen observers, as are today’s hunter/gatherers.
Even finding a mate may be entwined in smell. The role of pheromones (chemicals released by our bodies) in sexual attraction is still unclear, but research is uncovering some of the strange ways scent alters behavior.

For example, newborns are guided to a mother’s breast by scent. It turns out the mother’s nipples give off odorous molecules that allow the baby to home in on its food source. And here’s another nippily fact: odors given off by breast-feeding women can actually stimulate their childless female friends, although the exact “randy” chemical has yet to be identified (to the dismay of all you males).
As impressive as our sense of smell may seem, it pales in comparison to the majority of our faunal friends. Bears have the most impressive sniffers. Black bears have been known to hoof it eighteen miles to track down prey. Grizzlies can smell a carcass even if it’s underwater. And male polar bears will trek a hundred miles if they catch a whiff of a receptive cow. That’s a long way to go for some tail…

And here are a few other samplings from the animal kingdom: elephants can smell water from as far away as twelve miles, even if it’s underground; snakes smell via their tongues, catching scent molecules and processing them via specialized organs in their mouths; and finally, the most impressive of all, the male silk moths, who can detect as few as two pheromone particles exuded from the female from six miles out!
Although our noses don’t measure up to our critter counterparts, we corner the market on smelly sexual fetishes. I present to you “eproctophilia.” Believe it or not, there are folks out there turned on by the smell of farts. Eproctophilia is another form of paraphilia (which we discussed last week in Dead and Lovin’ It). It’s a crazy, crazy world out there…

Smelling is part of our evolutionary heritage. It is hardwired into our brains and is one of five primary senses that allows us to navigate our world (along with sight, hearing, taste, and touch). And it’s the direct association to the emotional centers of the brain that makes smell such a powerful trigger. Think about some of your favorite smells. What do they remind you of? A scene from your childhood? A long-dead relative? A favorite place? Smell can instantly transport us to a time and place far removed from the present. So take a deep breath and lose yourself in a memory.

As for my favorite smells… a windswept beach, a wood fire at night, and bacon!!

For your entertainment, here is a video of a couple of lemurs in a "stink fight," where they smear their tails with scent to ward off rivals. 

Friday, October 11, 2013

Dead and Lovin' It

Have you ever seen a dead body? By the time we’re adults, most of us have attended a funeral or two. It’s a select few who go through life without actually viewing a corpse.
I’ve always had a fascination with death. From the time I was very young, I wondered about that thin line separating the living from the dead, and how, in an instant, life can be extinguished, leaving behind the shell of an individual.

I saw a lot of death as a medic. From homicides to suicides, accidents to natural causes, death was pervasive. And now, as a bioarchaeologist, I’m pretty much dependent upon the dead, since I rely on their skeletons to provide information about the past. I guess death and I are forever in collusion…
So it’s only natural for me to be curious about customs surrounding the dead. I’ve already touched on the theme of death in July’s Dead and Buried, where I ruminated over the concept of burial. However, the range of funerary treatments is as vast and varied as culture itself, for death is the one aspect of life that demands universal participation. It’s gonna get us all.

When the body dies, decomposition sets in, unless, of course, you’re lucky enough to croak on a glacier. In forensics, decomp is broken down into two general stages. Autolysis occurs when fluids that normally reside in the intestinal tract are released and start digesting the body. Putrefaction follows as bacteria within the body reproduce unhindered. As the bacteria work, they release gases; thus the characteristic bloating. This is also the stage where insects descend, since they find the gases irresistible.

It’s the messy process of decomposition that has compelled most cultures to devise elaborate means of slowing or halting the process. Embalming, mummifying, and torching are all methods of avoiding a stinking corpse.

But I’ll save funerary customs for another week. Today, let’s talk sex. Not just your average, everyday sex - I’m talkin’ sex with the dead.
Known formally as necrophilia, sex with the dead is not a modern construct. Even the ancient Egyptians knew to guard the bodies of beautiful women. They’d hold onto them for a few days until decomp set in, just to ensure the bodies weren’t diddled during embalming.

Today, psychologists identify three types of necrophilia. First, there is the harmless practice of fantasizing about the dead. These individuals typically don’t act on their desires; they’re usually satiated by deadly daydreams. Second are those who have access to a corpse and simply go for it. Makes you wonder about the quizzical grins of morticians… Third are the hardcore necros. These are the ones who kill in order to have a corpse at their disposal. I advise you to steer clear of these guys (or girls!).
Necrophilia is a form of paraphilia: a condition where a person’s sexual arousal and gratification are tied to abnormal or extreme behaviors. Think of them as the skydivers of sexual dysfunction. Paraphilias also include pedophilia, voyeurism, and S&M, among others. As prevalent a role as sex plays in culture, it’s no wonder we have a whole slew of deviancies associated with it.

On rare occasions, necrophilia is partnered with other dysfunctions. Take Jeffrey Dahmer, for example. Not only did Mr. Dahmer kill, mutilate, and violate his young male victims (typically in that order), he also served them up for dinner. Jeffrey was indicted on seventeen counts of murder after one of his potential victims made a hasty escape. The boy managed to flag down a few officers, whom he then led back to Dahmer’s lair. There they discovered human heads scattered throughout the apartment, a plethora of body parts in the fridge, and a photo montage depicting his gruesome hobby. His arrest brought an end to his grisly pastime, but you can imagine what the cleanup entailed...
Fun fact: the term for ingesting the flesh of the dead is necrophagia… Cannibals, on the other hand, tend to prefer fresh meat.

Psychoanalyst Erich Fromm mused on the character traits of necrophiliacs in his book, The Anatomy of Human Destructiveness. He viewed these individuals as products of social evolution and listed their personality traits as follows: Use of language that includes numerous death-related words, dreams involving death or dead parts, and an interest in sickness. Holy S!#t!! He just described the entire audience at our last bioarchaeology conference!
To avoid being labeled a necrophiliac and to assure you I have no intention of “digging up” my next date, I’ll close by saying that necrophilia encompasses a wide range of dysfunction, but not necessarily those of us in the skeletal biz. I’ve never been sexually aroused by the dead, despite being surrounded by an abundance of bone.

So on behalf of all bioarchaeologists, I proudly proclaim that, although we are fixated on the dead, we're not out there lookin’ to get lucky.
Didn't get enough? Here's a great article on necrophilia by Rosman and Resnick.
Catch you next Friday and don't forget to share!

Friday, October 4, 2013

Below the Equator...


I brushed the dark earth aside and the first glimpse of a skull appeared. Slowly, a delicate profile emerged from the grave. I lay beside her – my arm extended, brush in hand, as I worked to expose her torso. She had been buried over thirteen hundred years ago, in a cemetery tucked among the dunes along the North Sea, in the shadow of the medieval castle, Bamburgh. I was midway through my PhD and had travelled to northern England to hone my skills as an archaeologist. Her cemetery was my classroom.

The shape of her bones indicated she was female: the high arch of her forehead, the slender angle of her jaw, and especially her pelvis, which exhibited the telltale architecture of a body designed for childbearing. In bioarchaeology, where we read the past through the skeletons left behind, the pelvis is one of the most effective means of assessing the sex of an individual. But it’s the fleshed pelvis that really marks the difference between males and females. Let’s explore…

We’ve already covered the male anatomy (see A Natural History of the Penis), so today we’re zoning in on the female form. The subject is long overdue, for the female anatomy, though frequently splashed across screen and page, is the more mysterious of the sexes. Perhaps this will clarify things.
Although men and women look very different, they actually possess some of the same private parts. In fact, during certain stages of development, our genitalia are indistinguishable. Like men, women have a pair of gonads (ours are called “ovaries”), although unlike men, ours don’t swing between our legs. The ovaries are tucked in the abdomen and connect to the uterus via the fallopian tubes.

The uterus is a flexible, muscular pouch that can expand to accommodate a growing fetus. It’s also the source of those miserable cramps women suffer each month, as it sheds its inner lining (a.k.a., menstruation). The uterus tapers downward into the cervix, which is connected to the outer world via that magical passageway, the vagina.
During the reproductive years, an egg is released each month by one of the ovaries. The egg enters the fallopian tube, makes its way toward the uterus and the countdown begins. The egg has a seventy-two-hour window during which it can be fertilized. Sperm can survive for several days once they’ve been deposited – something to keep in mind for all you daredevils practicing the “rhythm” method of birth control.

Side joke: What do they call people who practice the rhythm method? Parents!!

But back to the female anatomy…
Since most women understand the fundamentals of their inner anatomy and most men couldn't care less, let’s concentrate on the outer parts, for this is where men can lose their way. So consider this as not just an anatomy lesson, but a means of improving your (and especially her) sex life.

It may come as a shock to you boys, but women actually have three holes down yonder and it behooves you to know the order in which they reside. The urethra sits just in front of the vagina, which in turn is positioned in front of the anus (another orifice you guys seem obsessed with). But most important for sexual arousal is the female version of the penis – the clitoris.
Pay attention!

The clitoris stands at the front of the line, just before the urethra (memorize the acronym CUVA: clitoris, urethra, vagina, anus). Like the penis, the clitoris contains erectile tissue and, like the penis, it becomes stimulated when stroked. Arousal of the clitoris is fundamental to a woman's achieving orgasm, so instead of being mesmerized by the boobies (although they require attention, too) or making a beeline for the vagina, you boys should be homing in on the “joy button.” Take your time, do it right and I guarantee you’ll receive your just rewards.
As a cultural side note, you’ll be amused to discover that for thousands of years, the vagina has evoked fear and intimidation, resulting in outlandish legends concerning its dangers. The myth of the vagina dentata – literally a “vagina with teeth” – dates back to the Greeks and is rooted in the belief that the female sex contains hidden perils. Succumb to our charms and risk castration – or worse! Obviously the stuff of fiction, but it pays to be careful.

I hope this little lesson has clarified that murky zone of the female genitalia. Yes, it can be tricky, but a little knowledge goes a long way. So I wish you a safe and fruitful journey, and should you have the opportunity to exercise your newfound knowledge, be meticulous and be sure to glove up!

PREVIEW: Since we now have a thorough understanding of both sexes, next we'll explore the bizarre and twisted world of necrophilia... If you're not familiar with the term, you will be next week! See you then and don't forget to share.