Six amazing facts about human bones

According to foreign media reports, bones are a very magical thing. People rarely realize that bone is also a living tissue. They repair themselves after breaking or breaking, but beyond that, they constantly reshape themselves based on our daily activities. In this article, we will introduce you to a few interesting facts related to human skeletons.

1. Not everyone has 206 bones

Textbooks state that the human skeleton consists of a total of 206 bones. But when a baby is born, the number of bones in the body is as high as more than 300. These bones are initially cartilage and then mineralized in the first few years of life. In this process, some of the bones fuse together.

Some people are born with more bones than others, such as an extra rib, finger or toe. Some people even grow extra bones as they grow. A recent study showed that as a result of improved nutritional status and weight gain, more and more people are growing back into "bean bones" (a small bean-shaped bone located behind the knee).

2. The height of human bones will constantly change

A child's height changes more rapidly in the best-selling years after birth. By mid-to-late adolescence, we have basically reached our adult height. But even if the bones no longer grow, the height can still change.

The bones at the joints are covered with a layer of cartilage, a rubbery layer of tissue made up of water, collagen, proteoglycans, and cells. After a day, the cartilage throughout the body, especially in the spine, compresses under gravity. So every night you will be shorter than when you wake up in the morning. Fortunately, after lying down and sleeping for one night, the cartilage will return to its normal size. In space, the microgravity environment plays the opposite role: astronauts can increase their height by 3% after a space mission.

Not only cartilage, but even the bones themselves become shorter under the influence of impact forces. Scientific studies have shown that the impact of running can temporarily shorten the tibia by 1 millimeter.

3. Only one bone is not connected to other bones

Most bones in the human body do not exist in isolation, such as the hip bone, which is connected to the thigh bone. But this is not the case with all bones, the exception of which sells well is the hyoid bone.

The hyoid bone is U-shaped and located at the base of the tongue, fixed by the muscles and ligaments at the base of the skull and the upper jaw. This bone allowed humans (and Neanderthals) to speak, breathe, and swallow.

Hyoid fractures are very rare. If a broken hyoid bone is found at autopsy, it may be used as evidence of strangulation or self-hanging.

4. Bone marrow is not just about filling the inside of bones

Longer bones, such as the thigh bone, are filled with bone marrow made up of fat cells, blood cells, and immune cells. The bone marrow in a child's body is red in color, reflecting the role bone marrow plays in the production of blood cells. The bone marrow in the adult body is yellow, which contains 10% of the body's fat. For a long time, it was thought that fat cells in the bone marrow were useless than to fill space. But scientists have recently discovered that the fat inside bones actually has important metabolic and endocrine functions, which can affect the health of the whole body.

5. Smaller bones are in the ears

The smaller bones of the human body are the hammer bone, incus bone, and stapes, collectively known as the "ossicles". Their role is to transfer vibrations from the air to the liquid of the inner ear. These are not only smaller bones in the human body, but also bones that are popular since the age of 1 and do not undergo remodeling. This is important because changes in bone shape can affect hearing.

Hearing ossicles also plays an important role in archaeology and forensics. Because these bones are formed while the embryo is still in the mother's womb, isotopic analysis can help experts analyze the eating habits and health of the mother with the bones of an unknown adult.

6. Bones can cause pressure

The sympathetic nervous system is the body's coping mechanism in preparation for intense activity, the so-called "fight or flight" response. Scientists generally believe that this reaction is related to the body's secretion of adrenaline during stressful situations. But in a recently published paper, researchers point out that osteocalcin, released by osteoblasts, is a key hormone in the stress response.

Compared to other normal mice, mice fed in a special way that cannot secrete osteocalcin do not have a "fight or flight" response in an emergency. The scientists also analyzed osteocalcin levels in the body and found that osteocalcin levels in both blood and urine increased after the subjects' stress. In addition, osteocalcin also stops the "rest and digest" response of the parasympathetic nervous system in a relaxed state, thereby activating the "fight or flight" response.