What is Osteoporosis? - Definition, Causes & Treatment

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  • 0:06 Weak Bone Disease
  • 0:37 What Is Osteoporosis?
  • 1:46 Why Does Osteoporosis Occur?
  • 4:30 Clinical Signs.…
  • 5:19 Treatment and…
  • 6:46 Lesson Summary
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Lesson Transcript
Instructor: Artem Cheprasov

Artem has a doctor of veterinary medicine degree.

Osteoporosis affects more than ten million people and causes more than one million fractures in the United States alone. Everyone is at risk for osteoporosis, but women are especially vulnerable. Learn more about this condition, including risk factors, causes, signs, diagnosis, and treatment in this video lesson.

Weak Bone Disease

We've all seen little cartoon sketches or comedy movies about elderly people breaking this or that bone in some kind of hilarious mishap. We laugh at it when it's onscreen, but not when it happens to our grandmother. While certainly a fall can occur for any number of reasons, be it slipping on a banana peel or an actual fall down the stairs, one of the reasons the elderly are more likely to break a bone during such a mishap is because of a weak bone disease we're going to cover right now.

What Is Osteoporosis?

Osteoporosis is the scientific name for a disease in which bones become weaker, more fragile, and brittle, predisposing an individual to more cracks and fractures. This should not be confused with a similar sounding condition called osteopetrosis. The latter is a rare, inherited disorder that also predisposes a person to a greater risk of fracture as a result of over-hardening of the bone as opposed to the weakening of it. In any case, osteoporosis is a pretty famous condition, one that even a caveman who was out of the dark enclave for even a day would have heard of.

While men, cavemen or otherwise, can be affected by this condition, it's more common in women, especially post-menopausal women. Besides advanced age and sex, there are other factors that influence someone's likelihood to develop osteoporosis. Drinking alcohol, smoking, leading an inactive lifestyle, soda, and many other factors, such as metabolic diseases or other medical conditions, can predispose an individual to developing osteoporosis.

Why Does Osteoporosis Occur?

While the risk factors are many, the reason why osteoporosis occurs boils down to something like this. We tend to think of our bones as this hard and rigid structure. The reality is that they only become super hard and almost weapon-like after death. While you are alive, your osseous tissue, or the strong connective tissue that forms your bones, isn't as hard or unchangeable as you might think. That's because bone is an ever-changing state of proteins, cells, and hydroxyapatite, which is bone mineral that is comprised of calcium and phosphate.

While the mineral gives our bones their famous rigidity and strength, it's a protein called collagen that gives our bones a bit of flexibility. I sometimes like to think of this combination as a medieval flail. The ball is like a molecule of a really hard mineral of bone and the chain is like the stringy portion of bone that's attached to it. While the chain gives the weapon some flexibility, the ball at the end of the chain is hard enough to kill someone. That's sort of how bone is structured as well. It's a balance of strength and flexibility.

Additionally, I mentioned that cells play a part in our bones. These cells, called osteoblasts and osteoclasts, are responsible for shifting around, repairing, and modifying our bone as we live our lives. That's why bone is truly alive and ever-changing as we live and change ourselves! In short, osteoclasts consume bone and osteoblasts build bone. You can think of the osteoclasts as the construction workers that come by a road and begin to tear it apart, while the osteoblasts would be the crew that comes in afterwards to rebuild it.

In osteoporosis, either too little formation of bone or too much removal of bone occurs as a result of external factors, be it genetic or environmental. A specific but generalized example of one way this imbalance can occur can be seen in post-menopausal women. Estrogen is a hormone found in men and women that kills off osteoclasts to prevent the removal of too much bone. After menopause, the levels of estrogen in women rapidly decrease, allowing the osteoclasts to live longer and remove more bone.

This, therefore, leads a woman's bones, especially after menopause, to become weaker, more fragile, and more porous. That's how we get the name for this disease; 'osteo-' means bone and '-porosis' implies that something is porous.

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