Have you wondered why so many old people tend to develop rather pointed faces? It’s because of how bones develop.
Your bones are hidden practically all of the time, but they are a fascinating part of your body, about which you probably have had little knowledge.
Dr. Paul Brand describes bones and how they develop in his book, Fearfully and Wonderfully Made.
If you break a bone, as most of us have at some point in our long life, an elaborate and amazing process commences. “Excited repair cells invade in swarm,” as Brand puts it. Within a couple of weeks a “cartilage-like sheath called callus” surrounds the region of the break and “cement-laying cells enter the jellied mass.”
The repair cells are called the “osteoblasts.” They are like pothole fillers for the busted bone. Eventually, they break down the callus and replace it with fresh bone, Brand explains. Eventually, new bone covers both ends of the broken bone.
Hidden, as bones normally are, they don’t display their “flow of life” Brand says.
With magnification it’s possible to see the osteoblasts diligently replacing over aged bone matter.
When you were young, 100 percent of the bones in your body were replaced each year. So when you were, say five years old, you had not a remnant of your four-year-old jawbone.
Because of the nature of the bone’s DNA, the shape of your jaw remained the same. Only it was larger. As you reach the beginning of old age, about 18 percent of your bone gets replaced each year. But old bone doesn’t surrender its territory easily, Dr. Brand explains.
He notes in rather dramatic fashion: “It must be dynamited and vacuumed out,” For this stage of the bones to keep working, our body has what are called osteoclasts. These are a kind of demolition team.
These “clasts” are relatively large. They are jam-packed with “an average of ten to thirty nuclei, as if they need all the instructions they can assemble for their vital task.”
These clasts scavenge each bit of bone, one cell at a time. “They tunnel through the bone as easily as a mole through a lawn.” They are opening up holes for the blasts to fill. These blasts rejuvenate. Thereby they deposit a whole new supply of healthy fiber for the bone.
The clast cell leads a suicidal life. It has bored so violently that it burns itself up in about 48 hours and dissipates as waste.
The Blasts and the Clasts are actively at work throughout your life. The Blasts tend to dominate the first half of your life. They are busy laying down new bone in an orderly fashion necessary for growth.
Then, eventually, demolition Clasts outstrip the weary Blasts. So, in old age, the teeth sockets decrease in size, the chin “begins to protrude, the jaw angles in and the elderly are left with more severe, pointed faces.”
And this is why a bone fracture causes “trauma for the elderly.” Their Blasts are no longer up to the rigor of routine repair they were capable of in past years; bones heal slowly.
As old bones in your body, Blasts factor into their design necessary adjustments for stress. Brant explains: “All bone elements are arranged in perfectly engineered intersecting lines of stress, like the girders on a steel bridge.”
If you break your foot, for example, the pain while it heals make you take shorter steps. Gradually, those lines of stress in the heal bone will change and end up at a new angle to the leg, Brant says. “The Blasts will accommodate to meet the new challenge.”
As we know, if we exercise our legs or lift barbells, as I do twice a week, this stress stimulates bone growth. If you have to stay in bed for a long period of time, you can lose 50 percent of the calcium in your bones.
Astronauts in space and free of gravity don’t get customary exercise. So, they lose 20 percent of the calcium in their bones.
That’s why taking walks are important for seniors — to ward off the dangerous broken hip from a fall. “Walking, lifting, flexing, any activity sends electrical currents through bones to generate growth,” says Dr. Brand.
Tait Trussell is an old guy and fourth-generation professional journalist who writes extensively about aging issues among a myriad of diverse topics.