While many people immediately think of serious crimes and scary horror movies when they say skeleton, the skeleton is much more than that. We need our skeleton, we cannot live without it. The skeleton provides support and shape to our body. It protects important organs. It allows us to move. And also very important: the skeleton makes our blood cells. All in all, reason enough to take a closer look at the skeleton.
The skeleton
Our skeleton consists of bones, but what is a bone actually made of?
Bones consist of bone tissue. Bone tissue consists of fibers with all kinds of calcium salts in between.
Are all bones made the same?
There are two types of bone tissue that make up a bone
- compacta (compact bone tissue)
- spongiosa (spongy bone tissue)
What is a long bone?
A cannon is a bone. It is a long shaft of compacta, ie of compact bone tissue. A cannon is filled with bone marrow. In young animals and children this is red bone marrow, it makes blood cells. In adults and adult animals, the red bone marrow is mainly in the flat bones and in the short long bones. Because they no longer grow, they need less red bone marrow.
Can bone marrow also have a different color?
There is also yellow bone marrow. This consists of adipose tissue.
Where do we find the spongy bone tissue or spongiosa?
All long bones are thickened at the ends. Here they do not form a joint surface. These thickenings consist of spongy bone tissue or spongiosa.
Why does it hurt so much when someone kicks your shin?
Your shin is very close to the skin, which gives it little protection against hard kicks. All bones are further surrounded by a periosteum. With a difficult word this is called periosteum. Peri means around it and os means bone. There are many sensory nerves in the periosteum, which makes a staircase hurt a lot. Inflammation or piercing of the periosteum also hurts a lot.
Why is there a periosteum around the bone?
The bone can grow because bone-forming cells come out of the periosteum. These form new bone cells on the outside of the bone tissue, making the bone thicker.
But don’t bones also get longer, not just thicker?
The longitudinal growth of the bones occurs from the growth plate. This is a cartilage disc on the border of the shaft and the thickened end of the long bone. Here bone cells are deposited so that the bone grows longer. The growth plate becomes ossified when the body is fully grown.
Are all the bones of the skeleton together?
All bones are interconnected in the body. This may be because bones have fused together, such as in the skull. Bones can also be connected by a connective tissue, such as the pelvic bones. Bones can also be connected to cartilage, such as in the joints. When a body is dead and ultimately only the skeleton remains, not all bones are together, because the connective tissue and cartilage decay earlier.
What exactly is a joint?
A joint is a place in the body where two or more bones meet. There is a gap between the bones, which we call the weight gap. This gap is filled with lubricant, the synovial fluid, which we also call synovia. The synovia ensures that the bones can move in relation to each other, without causing irritation.
A joint is strengthened and stabilized by a joint capsule and ligaments. These are strong, tensile-resistant connective tissue tissues.
The end of the bone, what we call the articular surface, is covered with smooth cartilage. The cartilage may have auxiliary structures to fit the joint. You can see this for example at the meniscus in the knee. The cartilage also helps as a shock absorber.
