The human skeleton is a complex and impressive structure made up of a living tissue. It serves as a support for the body and allows movement. It also protects organs and makes blood cells store minerals and fat. The skeletal system might seem less dynamic than most of our body’s organ system, but it has many remarkable attributes you probably don’t know. Skipping the basic facts you have likely learned from your science teacher, here are some interesting facts about and related to our bone system:
1. Babies have more bones than adults.
Infants are born with 300 bones, but by the time they reach adulthood, they only have 206. There’s an explanation for that. Babies’ bones are made up of smaller component bones which are not yet fused and fully developed – that’s why we need to handle them with care. This also makes it easier for the baby to pass through the birth canal. The bones fuse, harden and grow over infancy, childhood, and adolescence. The only bone fully grown at birth is in the ear.
2. The hardest and strongest bones in the body are the thighbone and skull.
The femur, or the thighbone, is the strongest bone in the human body by most measures. It is also the longest as it extends from the hip to the knee. The femur can resist a force of up to 1,800 to 2,500 pounds. It can only be broken by huge amounts of force like those of a fall from an extreme height or a car accident.
Another remarkable hard bone in the human body is the largest in the skull: the mandible or the jaw bone. It is also the only movable skull bone that can hold the teeth and move during one’s lifetime while withstanding repeated and significant levels of stress.
3. Human bones are stronger than steel and concrete.
While steel and concrete are much heavier than the human bone, pound for pound, the bone is the stronger material. It is about five times stronger than steel by weight. A cubic inch of bone can bear a load of 19,000 lbs., which is about the weight of five standard pickup trucks, making it four times as strong as concrete.
This is mostly because of the human bone’s cellular structure. The osseous, the bone’s primary tissue, is a hard, spongy, honeycombed material that is mainly composed of calcium phosphate, which gives the bone rigidity while remaining lightweight.
4. Humans are taller in the morning than in the evening.
The cartilage between our bones gets compressed by standing, sitting and other daily activities as the day goes on. By the end of the day, we’re about one centimeter shorter.
5. Our bones are automatically replaced over time.
In addition to that, the human bone is constantly being worn down and remade like the skin, and every 10 years, we essentially have a new bone. During humans’ younger years, a bone formation process known as modeling creates an opportunity for the new bone to form while the old bone material is removed from a second site inside that bone, enabling bone growth. It’s a lifelong process that can also control the replacement and reshaping of bone injuries and damages.
6. Pelvic joints adjust to support a pregnancy.
To accommodate birthing a baby, the female human body makes a lot of adjustments, and it includes the skeletal system. The laxity of the pelvic joints is affected by a reproductive hormone called relaxin, which makes joints more stretchable and loose to aid in the delivery of a baby. However, this stretching and loosening effect could make pregnant women more unsteady on their feet. Studies suggest that with elevated relaxin levels, other joints might experience instability and weakness.
7. The skeleton influences sugar metabolism.
Did you know that the skeleton is also part of the endocrine system? When we eat, the gastrointestinal tract releases a variety of signals like insulin-stimulating hormones. These hormones help us digest our meals better and store energy and fat. Because the bone forming cells, called osteoblasts, have the same cellular origin with muscle and fat cells, it is found that the skeleton has a role in energy metabolism. Osteoblasts produce a hormone called osteocalcin, which is secreted to regulate blood sugar levels. It also mitigates storage of fat. Because of that ability, we can conclude that the skeleton can influence how the body regulates sugar metabolism as well as weight gain and loss.
8. Human bones can self-destruct.
Excessive exposure to cadmium can cause the bone to destroy itself by triggering premature apoptosis, or programmed cell death that takes place as part of normal growth and development. Also, if your body is lacking in calcium, certain hormones can leach calcium from your bones to try to balance the blood’s supply of this mineral. This is why calcium is important to maintain strong and healthy bones.
9. There’s a disease that causes a bone to vanish.
Like the rest of the body, the skeleton can also be targeted by rare medical conditions. The Gorham’s disease, also known as the vanishing bone disease or phantom bone disease, is a rare skeletal condition with unknown causes. It is characterized by massive bone loss, or osteolysis, in specific areas of the skeleton and can spread to soft tissue and adjacent bones. The symptoms vary, depending on the area where a bone is being lost, but generally, sufferers experience pain, swelling, weakening and increased risk of fracture. It can affect any part of the skeleton, but most of the people who had this rare disease experienced wasting of the bone in the skull, rib, shoulder, jaw, pelvic bones and spine. This mysterious disease can lead to death if it significantly affects the spinal cord as well as the ribs, which could compromise lung and heart function.
10. Smoking also affects bones.
We all know that smoking is dangerous to our health, but what most of us know is it destroys the lungs and other organs we have. Smoking is bad for our bones too, as it increases the risk of osteoporosis or weakness of the bone. This nasty habit deprives our bones of calcium through hindering the body’s use of vitamin D, which would otherwise help in transferring calcium to the bones – resulting in weak and fragile bones. It can also poison the osteoblasts and lessen the production of estrogen, a reproductive hormone that also increases the ability of bones to retain calcium.