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Spongy Bone (Cancellous Bone) - Definition, Structure, Functions

Spongy Bone (Cancellous Bone) – Definition, Structure, Functions

Spongy Bone Definition:

Spongy bone is especially porous in nature. it’s also called as cancellous or trabecular bone. It has a high vascularization and red bone marrow. Spongy bone is commonly observed on the ends of lengthy bones (the epiphyses), surrounded by using tougher compact bone. it could also be determined in the vertebrae, the ribs, the skull, and the joint bones. Spongy bone is weaker and softer than compact bone, however it’s far greater flexible. Spongy bone has a lattice like look due to the presence of a complicated network of trabeculae. The illustration beneath depicts spongy bone.

Structure of Spongy Bone:

Spongy bone is made up of cells called osteocytes that live in small cavities known as lacunae. The lacunae and their associated osteocytes are housed inside the bone’s trabeculae matrix, along side the bone marrow. Blood vessels convey substances for the formation of blood cells via the tougher compact bone to the spongy bone. Osteocytes near blood vessels can soak up vitamins and expel waste through canaliculi, which can be tiny interconnected channels at the surface of the trabeculae.The movement of osteoblasts, bone cells that secrete the cloth that bureaucracy the compact bone matrix, can convert spongy bone to compact bone. The lengthy bones in a human embryo develop thru this technique.

Spongy Bone (Cancellous Bone) - Definition, Structure, Functions

Functions of Spongy Bone

 

Storage of Bone Marrow:

whilst the trabecular matrix crowds blood vessels collectively and that they condense, bone marrow, also referred to as myeloid tissue, is formed. Unlike, compact bones, the spongy bones are very useful to save in addition to produce bone marrow which plays a key function in our body. In its medullary hollow space, compact bone shops yellow bone marrow, which is in most cases composed of fat. Spongy bone includes purple bone marrow, that’s used inside the procedure of erythropoiesis.

Site of Erythropoiesis:

In spongy bones, RBC produced almost at a charge of approximately 2 million cells consistent with 2d. The quite vascularized nature of the spongy bone, that could supply ok quantities of the glucose, lipids, amino acids, and hint factors required to make red blood cells, enables this fast production. when old and broken red blood cells die, they return to the bone marrow and are phagocytized by way of macrophages. This system takes place in the liver and spleen.

Reduces the weight of the skeleton:

The light weight nature of spongy bones performs a essential position in retaining the overall body weight balance as they’re plenty lighter compared to compact bones which has more density. This permits muscle groups to transport the limbs extra without difficulty.

Add strength and flexibility of bones:

Trabeculae offers the spongy bones it’s energy as well as flexibility as they’re typically fashioned along the pressure strains on the bone. Spongy bones are also accountable for surprise absorption as they may be found in decrease again in addition to decrease frame area for this reason facilitating in our capability to stroll, run and leap.

Mineral storage:

The human skeleton includes 99 percentage of the calcium and eighty five percent of the phosphorous mainly in frame. To make sure proper muscle and frightened gadget characteristic, the mineral content of blood have to be tightly regulated. when needed, minerals are speedy carried within the bloodstream, and this movement is generally mediated by way of hormones.

Evolutionary changes in Human Spongy bones:

The cutting-edge human skeleton is distinct in that it has a low trabecular density on the subject of its length. Spongy bone accounts for about 20% of the human skeleton. In comparison, it makes feel that a chimp’s skeleton is sort of completely made from spongy bone. Early human bones had been located to have a higher percent of spongy bone than cutting-edge human beings. To dig deeper into this finding, researchers currently compared the trabecular density of modern human skeletons to that of chimps and early human beings who lived thousands and thousands of years in the past. The motive of the take a look at was to decide whilst in human evolution trabecular bone density reduced. The observe’s findings suggest that lower trabecular bone density in contemporary humans is a latest phenomenon, maximum probable because of increasingly more sedentary life and a reliance on technology.

 

References

  • Habiba et.al. (2015). Recent origin of low trabecular bone density in modern humans. Proceedings of the National Academy of Sciences. 112(2), 336-371. doi: 10.1073/pnas.1411696112.
  • OpenStax. (2017). Anatomy and Psychology. [online textbook]. Retrieved from https://cnx.org/contents/FPtK1zmh@8.81:kwbeYj9S@4/Bone-Structure.
  • OpenStax. (2017). Anatomy and Psychology. [online textbook]. Retrieved from https://cnx.org/contents/FPtK1zmh@8.81:9SrcxH7k@5/Erythrocytes.

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