Blood

Ok, here’s the deal on your blood. As an average adult, you have about five liters of blood flowing through your veins. The entire volume is made up of four components; red blood cells, white blood cells, platelets, and plasma.

Red blood cells are red. They’re the little guys that do the heavy lifting by carrying oxygen around your body. They’re kind of like college students who are moonlinght as movers. Normally, these little guys are shaped kind of like a doughnut without the hole in the middle going all the way through. (More like a depression than a hole really.) However, these guys can change their shape in order to move through tiny capillaries. In addition delivering oxygen, red blood cells pick up carbon dioxide, a waste product of cellular respiration and the stuff you don’t want anymore. This is handy as it would be a waste of a trip if you had to have someone else come get this carbon dioxide and the red cells are right there anyway. When red cells are carrying oxygen they are bright red but deoxygenated blood (not carrying oxygen) is a really dark maroon color giving veins their ‘blue’ coloring.

Half your body’s red blood cells are replaced every seven days which is easy to understand when you realize that iIf all the blood vessels in your body were laid end to end, they would reach about 60,000 miles.

White blood cells are the gunslingers of the blood posse. They go around nuking, spraying, and slurping up all the little critters that you don’t want around like bacteria and viruses. The most common white blood cells are neutrophils and lymphocytes. Neutrophils are kind of like ‘the Blob’ and literally swallow their enemies alive through a process called phagocytosis (cell eating) which is really unpleasant if you’re the one getting absorbed. Lymphocytes are a lot smarter. They adapt their shape to destroy new viruses and bacteria that enter the body. While this time for previously unknown pathogens, your lymphocytes remember all their past encounters which prevents you from getting sick from the same illness in the future. (It’s good to know that every flu you catch is a different one. Vive le difference.)

Platelets are not very smart. They don’t have to be since their job is simply to find a breech in a vessel wall and throw themselves into it. They’re the ones who begin to form a clot when you cut your finger, kind of the Kamikaze of the blood system.

Red cells, white cells, and platelets are all formed in your bone marrow from the same stem cells.

Plasma is the fluid that carries all these cells around. It’s 90% water with a 10% smattering of proteins, electrolytes, glucose, vitamins, hormones, and cholesterol. (As far as I know there’s no salt and pepper.)

Addition Facts:

• On average, men have 5.2 million red blood cells per cubic millimeter while women have 4.6 million.

• Jewish dietary laws do not allow blood to be consumed in any way. Traditionally, salting and pickling purges blood from meat.

• According to Chinese folklore, nosebleeds are a sign of sexual arousal in men

The Placebo Effect

The Placebo Effect is the influence of a treatment that has no medical value but seems to have a beneficial effect. (Kind of like apologizing to your wife for something you didn’t do.)

Inject a close-to-celestial-discharge patient with salt water and give him a sugar pill, and for some reason, he’ s back up and running in no time. This is especially true for subjectively assessed disorders such as migranes, back pain, and depression, which are all just in your head anyway. The placebo effect may account for a large part of the therapeutic value we subscribe to medications which is good news for those medications that don’t really work that well, since at least you think they do.

(There’s a sneaking suspicion that that erectile dysfunction ad that tells you to seek a doctor if you have an erection lasting more than four hours is an attempt at giving you a big setup.) 

The placebo effect for pain medications has been at least partially explained by brain chemistry. When the brain experiences pain, it releases endorphins—chemicals that naturally act like morphine to relieve pain and make you really, really happy. Brain imaging studies have shown that when a person takes a placebo, it triggers the release of endorphins. Neurologically, it’s as if he had taken the illegal drug, but without the trouble of having to do shady deals through his car window.

There is also the less understood but equally powerful nocebo effect. Often, people who are told that they are going to experience negative side effects from a drug do, even if there is no medical reason for it. In one study, people were given a sugar pill and told that it induced vomiting. Later, 80% of them started throwing up, which is why it’s such great fun to be a janitor at nocebo testing clinics.

Similarly, in another study, women who believed they were going to die of a heart attack were found to be four times more likely to die of a hart attack than women with the exact same medical profile who did not think that they were at risk. Thinking sick may make actually make you sick which makes it quite possible that Richard Simmons will live forever.

In some areas of medical treatment, the placebo effect actually seems to be getting bigger. In studies of aintidepressants, the response rate to placebos has been increasing by 7% every ten years. In 1980, 30% of depressed people given a placebo improved without any other treatment; in 2000, it was 44%. This may be due to widespread advertising and heightened expectations for drugs. In general, the public has more faith in psychiatric medications than it did twenty year ago, which give placebos more power.

Additional Facts:

• The color of the pills may also have an effect on some patients. In one Italian study, blue placebos made excellent sleeping pills for women and had the opposite effect on men. (Perhaps because it looked like Viagra and perhaps just because they were Italian.)
  

• Painful injections may have more therapeutic value than ones that hurt less so remember to ask the physician for a really painful one.
  

Why do we have baby teeth?

Image from iStock Photo

“Baby teeth (also known as deciduous or milk teeth or nipple nashers) are widely found in the animal kingdom.

While fish and reptiles continuously renew their teeth and go through many generations of them in a lifetime, mammals have followed an evolutionary trend toward suppression of tooth replacement since we love our teeth more than fish love theirs.

The reason is not known, but because the cusp pattern on mammalian teeth leads to complex patterns of occlusion (that is, the way the upper and lower teeth fit together = biting), it’s likely that subtle differences in tooth shape that might occur with frequent tooth replacement could lead to malocclusion, a dangerous situation where food couldn’t be chewed properly and you talk funny which would make mammals look more ridiculous than we already are. It could increase cavities as well so it may be that mammals will do just about anything to avoid going to the dentist.

In humans and other mammals, development has been restricted to just two sets of teeth. Young mammals’ skulls are small, and it’s impossible for them to accommodate a full array of adult choppers so juveniles have cute little temporary teeth to fit in their immature, backtalking jaws. Once the bones of the cranium have developed to adult size the Tooth Fairy starts wiggling them at night and they fall out to the great satisfaction of parents and money hungry kids alike.

The process for initiating the formation of permanent teeth in humans is not completely understood. Normally, permanent teeth come in at about age six in humans and this appears to be part of a genetic development program whose temporal trigger is not yet known but may be the teeth jumping ship after being made to chew all sorts of stuff off the floor for the last five years.

There may be a few other factors as well, particularly expression of a protein called Pax-9, which is part of the paired box family of transcription factors. (Pax-9 should not be confused with K-Pax, that movie where Kevin Spacy thinks he’s an alien.)

(Transcription factors are proteins that bind to DNA and activate gene expression. The paired box family is a special class of transcription factors that govern pattern formation during organogenesis. These transcription factors were first discovered in fruit flies (love fruit, not gay). However, paired box genes are strongly conserved throughout evolution. In vertebrates they are implicated in the development of several tissues and organs, including the brain, limb muscles, kidney, eye, nose, and ear.)

Loss of Pax-9 function in humans is an extremely rare genetic disorder—known in just one family in the United States—but it results in the failure to produce adult molars and in the increased incidence of loss of the second premolars. This genetic link tells us that the switch for making adult teeth must involve inducing cells to make Pax-9.

A second genetic cascade, which occurs after Pax-9 expression, leads to the loss of milk teeth. The baby teeth start to get ‘wiggly’ because bone-remodeling cells dissolve the bony root and periodontal ligament by secreting digestive enzymes. It’s not know if these cells need this as food, or just like the taste.

As the enzymes break down the tooth root and surrounding connective tissue, the tooth loosens until it’s time for the old ‘dad and a string ploy’ to provide space for the adult tooth.

You'll need to take care of your teeth whitening on your on.

Why do we have wisdom teeth?

Tucked away at the back of your mouth are the the heavy mashers of the enamel world.

Anthropologists believe that your third set of molars (wisdom teeth), are the evolutionary answer to your ancestor’s early diet of coarse, rough food – like leaves, roots, and the occasional wiry squirrel – which required some major chewing power and resulted those little front teeth being worn down to useless nubbins in no time.

Your current diet with its softer foods and yogurt products (something your distant ancestors would have loved), along with marvels of modern technologies such as forks, knives, and Tom LeLanes new super-quite Juicer have relegated wisdom teeth to the status of just another lowly dental scare tactic. As a result, evolutionary biologists now classify wisdom teeth as vestigial organs, or body parts that have become functionless due to evolution. You know, like your coccyx.

From baby teeth to permanent teeth, tooth development lasts years. While your first molar erupts around the age of six and the second molar pokes it’s head above gum at around the age of 12, wisdom teeth, which begin forming around your tenth birthday usually don’t erupt until you are between the ages of 17 and 25. Because this is the age that you stop putting your body parts inside pencil sharpeners and pulling the ear hair out of feral dogs, the set of third molars has been nicknamed “wisdom teeth.”

Some people never get wisdom teeth, leading to the term ‘non-wisdom teeth people’, but for those who do, they may sprout anywhere from one to four – and, on very rare occasions, more than four. If you’re one of the unfortunates who get these extraneous, or supernumerary, teeth, it can lead to all sorts of problems.

Since human jaws are smaller than they used to be (possibly due to fashion), when wisdom teeth form they often become impacted, or suppressed, by the other teeth around them. (Evidently teeth are imperialist capitalists whose only wish is to subjugate their immediate neighbors.) If the tooth only partially erupts, food gets trapped in the gum tissue surrounding it which creates a perfect little home for bacteria leading to the potential for a serious infection and really bad breath. (Some people have bad breath without this.)

American Association of Oral and Maxillofacial Surgeons estimates that about 85 percent of wisdom teeth will eventually need to be removed. This dovetails nicely with the fact that Oral and Maxillofacial Surgeons are the ones who remove them.

The association recommends that patients remove wisdom teeth around 15 to 18 in order to “prevent future problems and to ensure optimal healing” and because no one cares if teenagers can’t talk for a week.