Anatomy of a Fire Truck

Fire trucks are so cool. The next time you hear the ear-piercing wail of a siren, the bone-rattling blast of an air horn, stop what you're doing and take a moment to appreciate their beauty.

Referred to as ‘engines’ by those in the biz, these high-tech monsters not only deliver personnel and equipment to emergency scenes, they can turn night to day via elaborate lighting systems, supply heavy extrication tools via powerful on-board generators, and, most importantly, deliver vast amounts of water to ripping house fires. They are mechanical marvels.

As a thirteen-year veteran of the fire service, I came to know these awesome machines intimately. As a firefighter, I rode backwards in a cramped jumpseat, sweating my ass off in summer, freezing that same tail in winter. As an engineer, I wove through the streets of downtown Orlando, barely missing the transients and tourists that leapt from my path. And as a lieutenant, I led an aggressive crew of professionals as we answered the endless emergency calls throughout the city.
Engines are the heart and soul of the fire service, and I can’t help liken them to the human circulatory system (indulge me for a moment).

Through an extensive network of hoses, an engine delivers vast amounts of vital water to awaiting crews, enabling them to extinguish flames, protect exposures, and prevent the spread of fire (you see where I’m going with this). In comparison, the human circulatory system moves blood throughout the body via its own extensive network, transporting oxygen and nutrients, fighting off pathogens, and regulating the body’s temperature.

An engine typically carries an impressive five hundred gallons of water in its tank.  An average adult totes around five liters of blood, depending on that person's size and weight. An engine depends on a centrifugal pump to move water. The pump is located beneath the engine mount and is controlled by a gauge located at the pump panel on the side of the truck. The engineer adjusts the truck’s RPMs to regulate the pressure within the hoselines. Too much pressure, the firefighters at the end of the hose become airborne. Too little pressure, their line goes limp.

Likewise, the heart, that fist-sized mass of striated muscle, pumps on average seventy beats per minute. That’s over four thousand beats per hour, over one hundred thousand beats per day. Many factors affect the pressure within the body’s vessels. Too much pressure can bring on stroke, heart attack, and internal damage to the system. Too little pressure and vessels collapse, organs fail, and the individual perishes.

Engines rely on frequent maintenance to keep their mechanisms functioning properly. Transmission fluid, oil, and brake and hydraulic fluid must be maintained for the engine and its pump to work effectively.

Similarly, the human body must be maintained to sustain a healthy heart. Lack of exercise can reduce the efficiency of the pump. Without it the heart, like the rest of the body, becomes sluggish and lazy. Coronary artery disease and alcoholism can also affect the heart muscle, causing a condition known as cardiomyopathy , rendering it inoperable. Without a transplant, the patient may die.

Valves throughout the engine prevent a backflow of water within the engine’s pumping system. Valves also regulate the amount of water that flows to each hoseline.

The heart also has valves, four of them to be exact, which keep the blood flowing in the proper direction. Leaky valves can cause overwork within the heart, which causes blood to back up into the lungs. This is commonly known as congestive heart failure. Valves also reside within the veins, those vessels that carry deoxygenated blood back to the heart. When these valves fail, blood can back up and engorge the vessels, creating that common condition in the legs: varicose veins.

An engine at a working house fire must have a supply line before it can provide multiple lines of attack. The line is laid from a hydrant and connected via an intake to the engine, providing an unlimited supply of water. Without a proper supply, the engine will quickly exhaust its tank. The hoseline will wither, the pump will cavitate, and the firefighters on the attack end will get cooked. Not a good scenario.

Without a proper blood supply, there is equivalent chaos in a human. Say an unrestrained (stupid) driver has a head-on collision. As his body is hurled against the steering wheel, his aorta – that large vessel that arches off the heart to supply the body – is torn. As the blood escapes into the chest cavity, pressure within the vessels drops, circulation to vital organs diminishes, the patient loses consciousness and death quickly ensues. Like the dry engine, not a good scenario.

So you seee, fire engines and the human circulatory system have much in common. Both are mechanical wonders that deliver vital fluids to their constituents, both depend on a pump and hoses to deliver these fluids and, when operating properly, both are beautiful to behold.

Here's a great read on the life of a firefighter (and a shameless plug:)

http://rachelwentzbooks.com/

Disfigured...

When I was a child, I was accident prone. During the three years we lived on the Philippine Islands, I broke my arm, knocked out my two front teeth, tore the flesh from my foot, and nearly lost my right eye. But the most serious accident happened when I was simply sitting in a chair.

It was one of those folding camping chairs. I was holding on to the scissor-like frame when it collapsed, snipping off the tip of my middle finger. My parents rushed me to the hospital (again) where a kind physician bandaged my finger using a small mirrored splint. I stared in wonder at my maimed hand as my weary parents drove the familiar route home from the ER. (In the photo I'm sporting the bandaging from the finger amputation and foot injury)

From that point on, I was self-conscious about my finger. Being right-handed made it difficult to hide the disfigurement, no matter how hard I tried. I felt everyone was looking at it, especially other kids. I carried it around in shame.

It wasn’t until the fifth grade that an incident made me come to terms with my unsightly appendage.

Her name was Ruth, and she had the misfortune of being born with only two fingers on her left hand. They weren’t even normal fingers, they were claw-shaped and gnarled. She rarely spoke and moved through life with her hand in her pocket.

Our class was assembling on the playground for that most barbaric of childhood sports, dodge ball. As we fanned out to form the circle, I noticed the other children. They were quickly moving away from Ruth, cutting their eyes and sharing knowing smirks. No one wanted to take Ruth’s hand. She stood staring at the ground, her hand buried deep within her pocket.

Why is it we fear things that are different? Why do disfigurements or deformities cause us such discomfort, when we know those who possess them are no different on the inside? 

Physical deformities have always fascinated me. As someone who specializes in the analysis of the skeleton, I’m most intrigued by skeletal disfigurements. They come in many forms. The process of creating a ‘normal’ skeleton is riddled with complexity; the potential for defect, extensive. Conjoined twins, malformed limbs, bones that are too brittle, those that are too soft - there are a million ways building a skeleton can go haywire. All it takes is a hiccup in the timing, a glitch in the biochemistry, and what you get is skeletal chaos.

The structures within the human body are formed from three distinct collections of cells known as the primary germ layers. The skeleton originates from the middle of these layers, the mesoderm (middle layer). This layer produces bone, cartilage, muscle, and the circulatory systems that support them. The ectoderm, or outer layer, forms skin, hair, nails, and the nervous system, among other things. And the endoderm, or inner layer, forms many of the body’s internal structures, such as the respiratory and digestive tracts and the bladder.

As these layers segregate and develop, they can be thrown off track by genetic abnormalities, illness or injury to the mother, or simply unsuitable conditions within the womb.

I’ve often tried to imagine what it would be like, living with a physical handicap. What does the world look like from the perspective of an achondroplastic dwarf, whose stunted limbs reduce him to a lower plain? What about those with severe scoliosis, where the spine zigzags down the back and the rest of the body is crippled from compensating? And imagine suffering from MOP. Myositis Ossificans Progressiva is one of those rare hereditary diseases that express themselves in frightening ways. Muscles and ligaments slowly ossify, encasing the victim within a bony tomb. As the muscles surrounding the ribcage harden, those controlling the jaw become fixed, and the patient can no longer breathe, no longer eat. There is no cure. There is n0 escape.

In a world where such skeletal disorders exist, it seems a miracle so many of us possess normal, functioning frames. We are the lucky ones.

So let me return to the playground. I stood for a moment, self-consciously staring at my own finger and glancing across the field at Ruth. And then I took a deep breath, strode over, and extended my maimed hand. She slowly withdrew her hand from her pocket and tentatively placed her disfigured hand in mine. And together, we became part of the circle. 

Our hands were a perfect fit. Our disfigurements seemed to complement each other. From that point on, I tried to keep the oddity of my hand in perspective.

So whenever you feel embarrassed about an aspect of your body, keep in mind there is always someone out there facing a greater challenge.

To paraphrase Einstein: “It’s all relative.”

Here's a great read on the subject!

Leftovers...

Three years ago, my appendix burst. The pain started in early evening; an intense throbbing around my umbilicus. I assumed it was payback for the gargantuan Caesar salad I had scarfed a few hours earlier, so I threw back an Alka-Seltzer and went to bed.

But the pain intensified and spread throughout my belly, eventually forcing me to kneel before the porcelain and surrender the salad. I spent the night writhing in bed.

By morning, the pain had migrated south, spreading along the base of my abdomen. I assumed it was a virus, slowly working its way through my GI tract. I walked around clutching my belly for two days before finally giving in and driving myself to the ER. (I blame my former profession for the procrastination. In the arena of firefighting, there is no worse stigma than being deemed a candy-ass.)

After a quick scan, they diagnosed the problem, whisked me off to surgery, removed the offending organ, and I was on the slow path to recovery. The doc said I was lucky to survive. By the time they cut me open, the appendix was a shredded mess, my belly a mass of infection. Complications would send me back to the hospital a week later, but I eventually recovered and the scar is barely noticeable.

My case is hardly unique. According to the University of Maryland Medical Center, over 70,000 appendectomies are performed each year in the U.S. And even with modern medicine, thousands still die, primarily from lack of proper diagnosis and prompt treatment.

But why is this? Why do we tote around an organ than has such potential to kill? And what the hell does this small appendage do, anyway?

For decades, we’ve heard the appendix is most likely a ‘vestigial’ organ - an evolutionary leftover. A body part that once functioned but, for some reason or another, has been dragged along the evolutionary path despite the fact that it no longer serves a purpose.

We are not the only species that possess such relics. There are cave-dwelling fish that still retain their eyes, despite being completely blind and spending their entire lives in the dark. Remnants of leg bones can be found buried deep in the hind musculature of pythons and boas, And even some whales retain vestigial legs; a throwback to when they once walked on land.

We humans are no different. In fact, the appendix is not the only vestigial organ we possess. Evidence of our evolutionary journey can be found on our skin, in our mouths, and even on our skeleton.

Let's start with the skin. When the hairs on your body stand on end – what we commonly call ‘goosebumps’ – you're exhibiting a carryover reaction from when our bodies were once covered with dense hair. By making the hair follicles erect, animals appear larger and more threatening. Think of a hissing cat in a defensive posture. And although we now lack the fur, the reaction persists.

Next come the teeth. Our dental arcade is reminiscent of the larger jaws of our ancestors. But over the course of evolution, our mouths have gotten smaller. Check out the jaws of the robust australopithecines; they were virtual nut crackers.  Ours, not so much. Our smaller jaws can no longer accommodate a full arcade, which explains why dentists make such cushy livings extracting wisdom teeth.

Our skeletons retain evidence of our primate kin. What were once our tails have been reduced to a few small bones that taper from the end of our spines. The coccyx is but a mere nubbin of its former self.

Even some of our responses are programmed from an earlier era. For instance:

You’re walking down a dark alley when suddenly, a man steps from an alcove wielding a knife. Your body automatically responds. Heart rate jumps, respirations increase, and the pupils dilate as a hearty dose of adrenalin is dumped into your bloodstream. Worst case scenario, you wet yourself.

All of this is part of the ‘fight or flight’ response, which is initiated by the amygdala – that region of your brain responsible for kicking your ass in gear when you’re faced with a perceived threat. This reaction and all its associated reflexes harken back to a time when we confronted physical danger on a regular basis. That same australopithecine was lucky to make it to adulthood without becoming a tasty morsel for a hungry leopard.

But back to the appendix… It turns out that little blob still has a purpose, even in our modern bodies. We now know it plays an important role in embryological development, producing compounds that maintain homeostasis within the developing fetus. In adults, it assists in the maturation of lymphocytes (white blood cells important for fighting infection) and even helps direct these cells to areas of the body in need of protection.  

So perhaps it’s not so vestigial after all. Who knows… maybe we’ll discover one day that our coccyx has some magical power. Stay tuned!

Here's a cool little video on the evolution of 'fight or flight' (although I take offense at the pterodactyl flying in the sky just before the caveman appears. Shame on University of Texas!)

My Cousin, the Lizard

Last weekend, a lizard took up residence in my kitchen. On nice days, I throw open the doors and bask in the glorious Florida sunshine. He must have sauntered in, taken a liking to the place, and decided to stay a while.

 All day, we went through the same routine. I would enter the kitchen on silent feet and scan every surface until I located that small splash of green. There he would sit, spread-eagle on the counter, leering at me with his reptilian gaze. I’d lunge for him and he’d hightail it back to the safety of the alcove between fridge and stove. By evening he was so emboldened that I found him lounging on the kitchen table, taking in the last orange of sunset streaming through the French doors. I made one last attempt as he skittered away, then I clicked off the light in disgust and headed for bed.

I didn’t see him for a few days, but I knew he was still around. I found his calling cards: tiny black turds capped with the telltale white salt deposit. He was mocking me.

It wasn’t until Wednesday night, as I was stepping into the shower, that I looked down and, lo and behold, there he was, peering at me like a peeping Tom from the base of the sink. I slammed the bathroom door, blockaded the jamb, threw a towel over the air vent, and gave chase. After a few minutes of awkward naked scrambling, I had him. I clutched his plump little body firmly between finger and thumb and headed for the front door in triumph. It was at that moment that I took a good look at him and couldn’t help but notice our similarities.

He and I, like all vertebrates, share the same body plan, which evolved some five hundred million years ago during the Ordovician Period. Prior to the evolution of the vertebrates, the sea of life (and by that I literally mean “the sea,” since it would require a spine for our ancestors to venture onto dry land) was populated by invertebrates. The spineless had the run of the planet for over two billion years before the vertebrates arose.

The earliest vertebrates were the jawless fishes. You’re probably asking yourself, “What the hell is a jawless fish and how does one eat without a jaw?” Well, these strange creatures lacked movable lower jaws and thus were forced to scrape or suck their prey. The evolution of jaws made for more efficient eating, which led to more efficient hunting; a definite edge when your underwater neighborhood includes arthropods the size of NBA All-Stars. Two other necessities for life on land included lungs and limbs. In order to venture out of the water, it helped if you could breathe the air and get from point A to point B. Thus, the vertebrate body plan.



As vertebrates, we have a front and back and a top and bottom, in contrast to jellyfish - those beautiful, translucent blobs. We have a backbone that encases and protects our spinal cord, with a head at one end containing a brain. We have four limbs: two fore (arms) and two aft (legs), and we exhibit bilateral symmetry - our halves are mirror images of each other (at least on the outside; our guts are another story). These are the basics of the vertebrate body plan. Over millions of years of evolution, our bodies have morphed into what they are today. All the strange and wonderful adaptations we see throughout the phylum Chordata are accents on a basic plan.

What I realized as I carried my little friend through the house was that our similar body plans alluded to a shared history. He is a cousin - many million years removed - but a cousin all the same. Our bodies speak of our common lineage. And with that thought, I released him onto the front porch and he disappeared into the night.


Here's a great read on the subject!

Musings on an Autopsy

Let me go back in time, back to when I was a budding paramedic student, before I even knew there was such a field as bioarchaeology. Let me tell you about one of my early experiences with death, one that altered my concept of the “body” and forever changed how I view life.

I was in my first semester of paramedic school, barely twenty-two years old. I had already completed my emergency medical technician certification – a semester of coursework followed by months of fieldwork – and during that time, I had been exposed to the dead. But as an EMT student, I was relegated to the periphery. Paramedic school thrust me to the forefront of patient care, where I was suddenly forced to make treatment decisions that would correct, stabilize, or kill my patients.

The paramedic curriculum is designed to help students come to grips with this new level of responsibility. The curriculum also forces students to confront death, so that they may develop the emotional callouses necessary for the gory situations they will invariably face in the field.

The highlight of my first semester was a trip to the county morgue, where we would spend the day observing autopsies. In reality, the visit served two purposes: not only were we forced to confront death in all its cold, antiseptic reality, but the autopsies would provide lessons in anatomy and physiology we simply couldn’t get from a textbook or in a lab. This experience would leave a lasting impression on me.

The autopsy room was an assault on my senses. Bright lights glared against steel countertops, the sting of disinfectant pierced my sinuses, and the sight of sheet-draped bodies made my stomach flip in nervous anticipation. I followed the tech to the nearest table. He slowly removed the sheet, folding it upon itself as he worked his way down the body of a young female. Her jaw lay slack, her eyes closed and sunken. Blood and cerebrospinal fluid seeped from her left ear and her fingers lay curled at her sides. Her fingernails were painted a frosty pink. Her toenails matched.

The tech explained the scenario. A waitress at an all-night cafe, the girl had been driving home from work early that morning when the driver's door of her pickup gave way. She wasn’t wearing a seatbelt and was subsequently dumped onto the pavement where she landed on her head, suffering a fatal skull fracture. As I grappled with the reality of her recent demise, the tech reached for the gleaming scalpel and the autopsy began.

He made the typical Y-incision, starting at each collarbone, meeting at the sternum, and then drawing a deep straight line through her abdomen, unzipping her with smooth efficiency. He then pealed back her flesh and proceeded to give me a tour of her anatomy.

It was fascinating. Her glistening organs lay tucked within her belly, her heart and lungs nestled beneath the protective arch of her ribs. What captivated me even more than their organization was their stillness. The heart no longer beat, the lungs didn’t inflate, her bowels had ceased their churning, and her stomach would never again growl.

He systematically removed each organ. Some were weighed, some were sampled by taking thin sections of tissue, which were deposited in small formaldehyde-filled containers where they floated in isolation. He squeezed her stomach contents, representing her last and final meal, into a jar as my own stomach lurched in response. After a few embarrassing dry heaves, I was able to regain my composure and the autopsy continued.

Despite its clinical setting, the procedure was strangely intimate. Her heart fit snugly in the technician’s palm as he gently placed it on the scale. He carefully lifted a pale ovary from her pelvis and, with a delicate finger, pointed to the small, shiny bulge that indicated she had been ovulating at the time of death.

When he made the large incision across the top of her head and folded her scalp down over her face, tucking it neatly beneath her chin, the woman no longer appeared human. Her body, lacking the animation of life, was but a collection of cells, tissues, and organs. She was no longer a person. She was now meat on the slab. 

I thought about her often in the following weeks. I still think about her, decades later. That day in the morgue altered my perspective of life, death, and everything in between. An autopsy tears a person down to their foundation. It reduces the individual to his or her once-working parts and what is left is the stillness and silence of a lifeless machine.

But she and all the other dead I encountered as a medic taught me a valuable lesson. Now, when I peer into an ancient grave or examine the bones of those that lived thousands of years in the past, I force myself beyond their death to what they were in life. I think about their dreams, their fears, and how different those dreams and fears must have been from those we cultivate today. And, although their lives speak of a different time, we share a common thread. We are all descended from those ancient Africans whose bodies, through the slow accumulation of traits, would eventually become us.

We’ll explore that topic next.

Introducing The Body Blog

When I was a child, my class took a field trip to St. Augustine’s famed Fountain of Youth. Immersed in the humid heat of Florida’s Atlantic coast, we drifted beneath ancient oaks, their limbs draped in Spanish moss, as our guide, sweating heavily beneath the bulk of his conquistador costume, wove the tales of that historic site. That trip would set a course for my life for it marked the beginning of my obsession with the human skeleton. But it also impacted me in another way: it was the first time I truly contemplated death. 

Not that I wasn’t already mesmerized by bones or naive to the concept of death. My first experience with both occurred following the death of our obnoxious parrot, Polly, who finally expired after years of screeching and bad behavior. We buried him with great ceremony beneath a dark umbrella of palm and for days, I contemplated the changes taking place within the shoebox housing his remains, wondering where his annoying little soul was residing, whose hand he was painfully pecking.

But it was in St. Augustine where I first contemplated my own death. After an exhausting day of trudging through history, our sweaty little group was shuffled into the final exhibit, which back then was an exposed burial ground where Native Americans had been interred some two thousand years before. I stared out over that cemetery, which held several adults and a few small children, and was shocked to realize that at one time, those pale dry bones had been animated in life; that the skeletons that lay before me once belonged to living, breathing individuals just like me and that, like them, one day I too would die.

That experience launched my obsession. Suddenly, I viewed my body not merely as a collection of tissues that enabled me to go about my daily business, but as a magical vehicle through which I experienced the world. My body, with all its inner workings, was life itself. And like all of life, it would one day come to an end. I was hooked.

Since then, my careers - as a former firefighter/paramedic and now as a bioarchaeologist - have revolved around the human body. As a medic, I dealt with devastating injuries and chronic illness, mitigating both as I frantically worked on patients, piecing together the fragmented remains of high-speed collisions, sending volts of electricity through hearts ambushed by sudden cardiac arrest, and plugging the holes of those peppered by gunfire amidst the violent streets of Orlando.

As a bioarchaeologist, I examine the bones of the long-dead in an attempt to interpret their life experiences: fractures resulting in angulated limbs, infection that settled blanket-like over the skeleton, dental disease that must have sent its host howling, and the creeping grip of arthritis resulting in gnarled and debilitated joints.

 This blog will be an extension of my obsession and a means of indulging two of my favorite preoccupations – the inner workings of the human body and how each of us are impacted by the culture in which we live.