Blood does come into contact with bones. Although bones are commonly thought of as solid and rigid structures, they are actually living organs that have a complex network of blood vessels running through them. These blood vessels serve several important functions within the bones.
Inside the bone, the dense network of blood vessels supplies the bone marrow, which is a soft, spongy tissue found in the center of most bones. Bone marrow is responsible for producing various types of blood cells, including red blood cells, white blood cells, and platelets. These blood cells are vital for carrying oxygen, fighting infection, and promoting blood clotting, respectively.
The blood vessels within the bone marrow deliver oxygen and nutrients to the bone cells, allowing them to function properly and maintain their health. In return, waste products produced by the bone cells are removed through the blood vessels. This constant exchange of substances helps to ensure the overall integrity and function of the bone.
In addition to the blood vessels within the bone, there is also a layer of connective tissue covering the outer surface of the bone called the periosteum. This tissue is richly supplied with blood vessels, which play a crucial role in bone healing and repair. When a bone fractures, the blood vessels within the periosteum are often damaged, leading to bleeding. This bleeding is what causes the characteristic pain, swelling, and bruising associated with a fracture.
The blood that comes into contact with bones is not only important for bone health and repair but also serves as a means of communication between different parts of the body. Various signaling molecules and hormones are transported through the bloodstream, allowing distant cells and tissues to communicate and coordinate their activities.
To summarize, blood vessels are present both inside and outside of bones. The blood vessels inside the bone supply the bone marrow and facilitate the production and maintenance of blood cells. The blood vessels on the outside of the bone, within the periosteum, are involved in bone healing and repair. Overall, blood plays a crucial role in the health, function, and communication of bones within the body.