Bigheads

The other day, I sat down to enjoy a giant grapefruit my coworker plucked from his accommodating tree. That’s the advantage of living in Florida: free fruit. As I admired the grapefruit's beauty and heft, it struck me that it was the approximate size of a newborn’s skull. I filed the information away, sliced into the fruit's meaty center, and feasted on its contents.

But it got me thinking about head size. Homo sapiens are a big-headed bunch. How we acquired such gargantuan gourds is a long and convoluted evolutionary tale, so I’ll stick to the highlights.

Natural selection is all about “advantage.” If a mutation bobs to the surface of the gene pool and happens to confer an advantage – whether it’s the ability to run a bit faster to elude a predator or a knack for exploiting a new food source – chances are he or she will leave more offspring and pass on that advantage. Through time and successful breeding, the advantage may become a staple, otherwise known as an adaptation. And the better adapted one is to his environment, the better his chances of survival.

So how did our heads get so big? 

Since our skulls, which serve as protective shell and handy carrying case, form atop the underlying tissues, we can blame our bigger brains.

Having a bigger brain is definitely an advantage. The more neurons you possess, the more complex the organ. But it’s not just overall size that matters. The brain of a walrus is about the same size as ours, but you won’t catch a pinniped performing calculus anytime soon. 

It’s the size of the brain in relation to body mass that really counts – what scientists refer to as the encephalization quotient (EQ). To give you an idea of EQs, take our hooved friend, the horse. Horses are pretty smart. They usually follow directions and can be trained to perform a number of nifty tricks. The typical equine has an EQ of around 0.8. Two of our other clever domesticates, dogs and cats, have EQs of 1.1 and 1.0, respectively. Humans, on the other hand, have EQs of around 7!
We are the true brainiacs. 

We’re still trying to tease out exactly when this advanced wiring emerged among our ancestors. By comparing skulls of our various kin, we can track brain changes over time. The neocortex, the outer region of the brain responsible for conscious thought, expanded by the time archaic humans emerged on the scene (around five hundred thousand years ago) and the temporal lobes, the regions on either side, are twenty percent bigger in modern humans compared to our predecessors. That’s important, since these lobes help us organize memories, aid in learning, and allow us to store information – all vital skills associated with the development of culture.

Our modern brains contain over a billion neurons and it’s this complex wiring that enables us to perform many intellectual feats that elude other animals. Reasoning, problem solving, forethought, and language are just a few of the impressive abilities made possible by our large brains (although some animals possess some of these skills to a limited extent). And it was the fine-tuning of these abilities that enabled Homo sapiens to invent things like complex societies and technology. You’d be hard-pressed to design a computer if you possessed the neurological complexity of a squirrel.

But our big brains come with a hefty price tag. For starters, they are metabolically demanding. About a third of the energy you produce each day goes to fueling that giant melon and without a constant influx of sugar and oxygen, it quickly dies. That’s why immediate CPR is so critical in sudden cardiac arrest. Ventilating the patient and performing chest compressions not only provide oxygen, but circulate it throughout the body to starving tissues. And the brain is at the top of the list, for without the brain, the rest of the body isn’t much use.

Another problem with a big brain is squeezing it through the birth canal. For this we can blame our mode of transport. Bipedalism (walking on two legs) places certain architectural demands on the pelvis. Our legs must be aligned below our trunks for efficient walking and running. If not, we’d walk like a crocodile, which can sprint for short distances, but will never win a marathon.

But a woman’s pelvis can only flex so far before things go wrong. That’s what can make childbirth such a dangerous endeavor. Hemorrhage is a common cause of maternal death, which is understandable when you consider the size of the newborn’s head in relation to the dimensions of the birth canal. Natural selection compensated by limiting pregnancy in humans to nine months. This way, the baby emerges before its head becomes too big to pass. The drawback: a defenseless newborn with an undeveloped brain, who is completely dependent on others for survival. Let’s face it… baby humans are basically helpless little blobs that can’t even lift their cumbersome noggins. Pitiful.

In closing, every physical attribute is a tradeoff. Bigger brains may make childbirth more problematic and gobble up much of our energy, but they enable us to do some amazing things. As I bang out this blog on my computer, I’m surrounded by the evidence of human ingenuity – all made possible by a big brain. The clothes I wear, the car I drive, the house I reside in, not to mention my electricity, phone, and medicines - none of these things would be possible without those demanding organs that sit atop our shoulders.

So hurray for the bigheads!

Here's a great read on the brain.

A Mother's Touch

With Christmas just around the corner, ‘tis the season for family gatherings. This provides either a blissful rush of joy or a pang of fear and dread, depending on your family dynamics. The holidays bring us together, whether we like it or not.

Family traditions are big around the holidays. I always flash back to the customs my mother instilled: tasteful decorations, plenty of homemade treats, and a mandatory live tree. The year we tried out a fake, I cried and cried.

Mothers have a tough job. There’s nothing more demanding than a newborn and that’s just the start of decades' worth of nurturing. I was lucky. My mother provided a loving childhood for me and my siblings and her life lessons still reverberate when I think back to all she taught me.

So stop and reflect for a moment on all that mothers do. For one thing, they signed on to giving birth to you and, let’s face it, pregnancy ain’t no picnic.

From the moment of conception, the woman’s body begins to change. Even before the pee strip turns blue, hormones inside her body are gearing up for the ordeal. Rising levels of estrogen and progesterone usher in the traditional “morning sickness.” The breasts swell (no complaints from the menfolk), urination increases, and fatigue latches on for a nine-month ride. Blood vessels dilate, leaving her hypotensive and dizzy; food is absorbed more slowly, causing heartburn and constipation; and her emotions climb aboard the pregnancy rollercoaster. Yes, it’s a joyful experience… and this is only the first trimester.

It’s hard for me to fathom my mother going through this four times, especially since I’m too gutless to even give it a one-time shot. But she came through like a champ and even managed to guide four kids to adulthood.

I’ve already discussed my haphazard childhood in April’s Disfigured. My injury calamities put my parents through the wringer, but mom was pretty savvy when it came to managing our maladies. She was stern when it came to illness (German roots). Whenever we tried to dodge school, she would nail us with her standard response: “YOU CAN MAKE IT!” It became a joke around our house. I could have lost a limb in a lawnmower mishap and she would have scooted me right out the door with my book bag, lunchbox, and a trauma dressing.

She was a master at tending wounds, and with four kids, she practically ran her own M.A.S.H. unit. Our bathroom was fully stocked with Band-aids, Neosporin, and baby aspirin and she administered each with the practiced precision of a drill sergeant. I remember her driving me to the hospital when I broke my arm, applying cold compresses when I knocked out my front teeth, and tenderly nursing me through chicken pox, measles, and a steady onslaught of ear infections (although according to my grandmother, she pushed my bassinet into the kitchen and shut the door after a particularly long night of my wailing).

She was also a patient instructor when it came to the mysteries of sex. I remember her gently explaining my baby brother’s bizarre genitalia (although because of her I still refer to testicles as “plump-plumps”). She explained the nourishment of the fetus when I pointed to his gross little umbilical stump, and she guided me and my sisters through the perils of menstruation with hands-on lessons in feminine protection.

So as you gather for the holidays, take a moment to appreciate your mother. Put aside any petty disagreements over clothing styles, makeup, or your choice of a spouse. Practice patience when she dictates how long the turkey should roast or points out the lumps in your gravy. And keep in mind how priorities and perspectives shift as we age.

My mother died of cancer on Christmas Day when I was twenty-three. Since then, the joy of the holiday is always laced with the pale taint of grief, the faint echo of loss. But I focus on the wonderful traditions she instilled, the warmth and happiness she so generously spread, and the valuable lessons she taught through her ever-patient instruction.
These things live on.

Happy Holidays.

My beautiful mother and her girls... I'm the goofy one in the underwear.

Googling the Body

I’ve always been curious about the body; my body, the bodies of my friends and families, even strangers’ bodies. Whether I’m at the gym, presenting a lecture, or simply in a crowded place, I can always amuse myself by checking out the bodies around me. We all do it. “People watching” is a most enjoyable pastime.

Although we are all one species, the range of dimensions and proportions of the human body are truly astounding. We’ve already discussed how size and shape relate to sports (October’s Size Matters), but this week I want to share a little-known fact about my blog.

I’ve been writing the blog now for almost nine months and ironically, much like a pregnancy, it has been a period of intense development – for me as a writer and for you as readers. I’ve watched my audience grow in leaps and bounds, reaching almost every continent on earth (will someone please share the blog with their buds in Antarctica!!).

What you may not know is that I monitor my readership through statistics provided via Blogger. I can track the number of page views, where in the world these hits occur, and – most interestingly – the Google searches that lead you to my page. 

Don’t panic! I can see the search terms but not who’s searching!!

So I thought it would be fun to share with you some of the bizarre things you folks are searching for out on this vast frontier that is the Internet. Join me as we Google the body.

Being a science geek, the task of analyzing subject categories and crunching numbers left me all atingle. I was able to separate the search terms into five general categories:

1.       Teeth

2.      Bones

3.      Blog Title/Website

4.      Sex (of course!)

5.      Oddities (and there are some strange ones in the mix…)

 People have a lot of questions about teeth and bones, which isn’t surprising. With over fifty teeth (baby plus permanent) and over two hundred bones in the average body, it makes for a lot of complexity and thus, many questions. “Childs mouth teeth xray” and “8 years old child teeth x-ray” are perhaps parents concerned with their child’s oral health or a researcher in need of a graphic (since I try to keep your attention via cool pics). There are also those interested in culture, like “8 teeth grillz,” although when I Googled this term, I came up with a YouTube video about ridding your dog of bad breath… Still don’t understand that one.

The bone questions come in a wide variety. “Bones of the face,” “appendicular skeleton,” “axial bones,” and “cranial sutures” were obviously searchers on an anatomical info quest. “Bones of the head quiz” was perhaps someone searching for a bit of nerdy fun.

Many find the blog via post titles or my name. "Anatomy of a fire truck” and “anatomy of hangover” are perfect examples. These are probably folks who have attended one of my lectures or heard about the blog via word of mouth.
So keep those coming!

It’s no shocker that many of you are cruising the Web in search of sex; therefore, it’s no surprise that my most popular post was September’s A Natural History of the Penis (you boys are obsessed!). But many who find my blog are trying to puzzle out the complexities of sex, and these complexities come in a range of issues.  

There are the curious, such as “females private parts” and the ever-present “penis length.” There are those who have had mishaps, like “anal scarring” or (my all-time favorite) “women’s private parts that stink.” And then there are those that move me. The searches that stem from a concern or insecurity, such as “teen penis growth.” Searches like this speak of our fears and worries; our feelings of inadequacy that flare especially during puberty (don’t worry, little buddy… it’ll get bigger!).

And finally, there are the truly strange searches that somehow land on my doorstep (although this says something about my blog’s content). For some reason there are a lot of questions about Chinese foot binding, which have found me via May’s Beauty of Feet. It seems I’ve also cornered the market on leeches. “Leech anatomy,” “leeches,” and “2013 leech saliva” are just a few examples of those who stumbled onto the blog via May’s Ode to the Leech. And then there are the searches I don’t even understand. Someone will have to explain to me what the hell “feet transfusion cartoon” means…

The Internet is a powerful tool – not only for providing information, but for bringing folks together. It thrills me to see this little blog being read by someone in Yemen, or the Sudan, or Thailand. To know that someone in Afghanistan, France, Malaysia, or Ukraine might be learning, or at least chuckling, because of something I wrote is incredibly rewarding. 

So keep reading and keep sharing, and I’ll try each week to bring a little bit of info your way.

Thanks to you all and I'll catch you next Friday!

Reminder: Read my book!!

Breasts for Hire

 I was cruising home from the gym the other morning, listening to the radio when the dramatic hyperbole of the local news station broke in.

            “YOU WON’T BELIEVE WHAT WE FOUND WHEN WE INVESTIGATED THE CONTENTS OF BREAST MILK BEING SOLD ON THE INTERNET!” they exclaimed in mock outrage. 

What made me gasp was not their groundbreaking reporting or the fact that there were contaminants in online breast milk. What shocked me was that there are loonies out there actually purchasing bodily fluids on the internet and feeding them to their newborns! WHAT THE HELL?!!

So I did some investigating of my own and it turns out breast milk is a hot item for sale on the web for parents who cannot provide their own. Granted, I don’t have kids so I’ve never had to deal with the trials and tribulations of breast feeding and, between you and me, any child of mine would starve, since I’m built like a prepubescent tween. But I was stunned that there are people out there who would purchase breast milk from a stranger and pass it on to their young. Isn’t natural selection supposed to weed out such insanity?

Not that the use of another’s milk is anything new. Milk surrogates have been around for thousands of years. So let’s spend a moment reflecting on this cultural practice, but let’s begin with a quick overview of the female anatomy. We've already covered the nether regions (October's Below the Equator) so let's head north. Welcome to “Breasts 101.”

Humans are mammals, meaning we are hairy, warm-blooded milk producers who nurse our young. Breasts are the means by which humans nurse, although their role in reproduction has been vastly overshadowed by their use in entertainment. Each breast is a complex structure of fat and connective tissue, lobes and lobules, ducts and nodes. All of this is arranged (somewhat) concentrically around a nipple, formally known as the areola.
 
Women produce milk in specialized cells called alveoli and the milk is carried via ducts to the nipples, where it is then consumed by the hungry newborn. What I didn’t know is that all women have about the same number of alveoli, regardless of breast size, so perhaps my kids wouldn’t starve after all…

But what happens when a woman can’t produce milk? Or, worst case scenario, the mother dies in childbirth? Enter the wet nurse.

The practice of wet-nursing goes back over four thousand years. Back then, if a woman failed to lactate, there were several remedies she could try before resorting to a surrogate: having her back rubbed with an oily concoction of fish bones, eating certain types of fragrant breads, or rubbing her malfunctioning breasts with poppy plants. If all else failed, a wet-nurse was brought in.

Wet nurses were typically members of the working class, if not outright slaves. Selection of the nurse would sometimes depend on the quality of her milk, which was gauged by the “fingernail test.” A drop of her milk was placed on the fingernail and if the milk slid off, it was considered too watery. If it clung to the nail when turned upside down, it was considered too thick. The ideal nurse produced milk that was “just right!”

In ancient Greece, wet nurses were not only utilized out of necessity, they were the preferred choice of higher status individuals. This trend carried on into the Renaissance, where aristocratic women were too busy playing cards and attending the theatre to worry about nursing. Besides, it was believed breastfeeding would ruin the figure and in fashion-conscious France, style always trumped suckling.

But as the practice spread, so did its opponents. Many believed the use of a wet nurse would harm the child by passing on physical or psychological defects from the nurse, especially if the nurse was a redhead! Redheads were believed to be ill tempered – a trait that tainted their milk. Others believed breast milk contained magical qualities meant to be shared between mother and child; thus it was a mother’s “saintly duty” to nurse her child.

Today, women have more options. Gals who cannot, or choose not, to breastfeed commonly use formula, and there are a plethora to choose from. Although formula lacks many of the benefits of breastfeeding, especially when it comes to immune response – it is still a practical option.

But should a parent insist on breast milk for their child, there are ways to obtain it without resorting to Craig’s List. The Human Milk Banking Association of North America (HMBANA) provides outlets for safe, pasteurized donor milk, as well as donation portals for women who have milk to spare.

So play it safe and use good judgment in your hunt for milk. After all, you wouldn’t accept a blood transfusion from some dude on the web.

Trust me... your baby will thank you.


Here's a great read on the history of wet nursing. Why am I suddenly hungry?...

 



In remembrance...

                               1918 - 2013