Spongy Bone
Spongy Bone Definition:
The spongy bone is a much porous kind of bone which is found in the animals. The spongy bones are also called Cancellous bones or the Trabecular bones. This bone is highly vascularized and consists of red bone marrow. Usually, spongy bone is situated at the end of long bones, with the surrounding of harder compact bone. This bone also presents in the ribs, inside the vertebrae, in the joint bones, and in the skull. Spongy bones are weaker and softer as compared compact bone, but it is much flexible too. It is referred by a lattice-like a matrix network, known as trabeculae which give it spongy shape.
What is Bone: Bone is basically one of the hardest parts of the skeleton within the Vertebrate. We can also say that skeleton is a collection of numerous rigid animal substances or structures like baleen or ivory. It is simply a collection of the hard huge calcareous connective tissue of which most adults vertebrates body is principally composed of.
Structure of Bone:
Structure of Spongy Bone:
The spongy bone is made up of cells, known as Osteocytes which lie in small cavities called Lacunae. The lacunae and their osteocytes are present in trabeculae matrix on the bone with the bone marrow. Blood vessels travel from the harder compact bone toward the spongy bone, by supply the materials which are necessary for the production of blood cells. Osteocytes located to close to the blood vessel, which can take on nutrients and expel the waste material with the help of tiny interconnecting channels found on the surface of trabeculae, known as Canaliculi. Spongy bone can also convert to the compact bones through the osteoblasts action. The bone cells which secrete the material produce compact bone matrix. It is done by this process which the long bones in a human embryo develop.
Functions of Spongy Bone:
Functions of spongy bone are given below:
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Storage of Bone Marrow:
Bone marrow is also known as Myeloid tissue. It occurs when blood vessel crowds together by the trabecular matrix and they condense. The compact bone is denser with having few open spaces, the spongy bone is good for form and stores bone marrow across the lattice-like trabeculae network. Compact bone is made up of primarily of fat in its medullar cavity, and it stores yellow bone marrow. The spongy bone has red bone marrow which is used in erythropoiesis.
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Site of Erythropoiesis:
The red blood cells create in the red bone marrow at the rate of approximate 2 million per second, inside the spongy bone. This faster production of red blood cells is possible by the highly vascularized nature of spongy bone that can transfer the adequate amount of glucose, amino acids, lipids, and trace elements, which is necessary to make red blood cells. when the old and damaged red blood cells are near to die, they return to bone marrow and here they phagocytized by the macrophages. This process lies in spleen and liver.
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Reduces the Weight of the Skeleton:
The low density and low weight of spongy bone balance out the heavier and denser compact bone in order to reduce the overall weight of the skeleton. This act makes it easier for the movement of muscle to the limbs.
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Adds Strength and Flexibility to Bones:
The trabeculae of the spongy bone work to form along with lines of stress, which gives the bone strength and the flexibility in this area. Spongy bone also lies in joints and work as a shock absorber when we jump, walk, or run.
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Mineral Storage:
The human skeleton has the storage of 99% of calcium and 85% of phosphorus. The blood mineral contents must be regulated in order to sure the proper functioning of muscles and the nervous system. It is a quick method mediated by hormones, which release minerals into the bloodstream when it is needed.
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Evolutionary Changes in Human Spongy Bone:
The human skeleton is composed of about 20% of spongy bone. The modern skeleton is unique because it has a low trabecular density as compare to its size. It makes sense that the skeleton of a chimpanzee is almost made up of spongy bone. By testing it shows that the early human bones were contained a higher percentage of spongy bone compare to modern human bones. The result of researches shows that in modern humans the lower trabecular bones density is a recent event and caused by increasing sedentary lifestyles.
Cancellous Screw
Cancellous screws are basically special type of screws which are designed for fixing the cancellous bone. They’re most typically utilized in the metaphysis of long bones. During the usage of these screws, we need to cut the skin deeply and require more extensive spaced threads as compared to other animal tissue screw. Since cancellated bone is very less dense than other animal tissue bone. Once, when the screw is inserted, screw threads cut path within the bone, i.e. Cancellated screws are basically self-tapping.
