The Skeletal System ( ESSAY )

Though your bones look all dry and austere, don't be fooled, they are actually alive. Bones are considered organs themselves because they contain more than one type of tissue. They are actually as dynamic as any of your organs is, and they are constantly repairing and you basically get a brand new skeleton in 7 to 10 years. They're job is way more than just providing you with support but also to :

• produce blood cells
• store energy as fat
• storage for calcium, phosphate, and other mineral.
• regulating blood calcium levels
• producing hormones osteocalcin
• protects against glucose intolerance and diabetes

So you see, they are basically another one of your organs. An average human body contains 206 bones, ranging in shape and size, from the tiny stapes in your ear, to the huge femur that makes up the entire length of your thigh. Autonomist often divide those bones into 2 categories :

• axial
• appendicular

Your axial bones is the bones that are found in your bodies vertical axis, like the skull, well basically all the bones that protect your other organs, ahhhh how heroic.... While your appendicular bones are, well, everything else. From there, your bones are generally classified further by their shape :

• Long Bones, the classic "dog-bone" style
• cube shaped Short Bones
• Flat Bones, the thin bones like the one that cover your brain
• Irregular Bones, the odd-shaped looking bones, like your vertebrae and pelvis

But despite their variations in size and shape, all bones have a similar internal structure. They all have a smooth, dense external layer of compact, or cortical bone around a porous, honeycomb-looking area of spongy bone. The spongy bone area is where typically you would find your bone marrow, which are found in two colors, red and yellow. The red bone marrow are responsible for creating blood cells, while the yellow bone marrow are the storage for your fat. The arrangements of these bone tissues, though, can be a little different from each other. Like in your flat bone, the spongy bone is in between the cortical bone, while in the long bones, the spongy bones are only found in the tip of the bones, called epiphyses. The basic unit of bones are called osteons. They are cylindrical, weight-bearing structures that run parallel to the bones axis. Look inside one, and you will see them look like tube inside of a tube. Each one of these tubes, called lamellae, is filled with collagen fibers. Now the tube that are in the tube, is filled with nerves and blood vessels. So there you go. A tour of an organ that you have known all your live, without you realizing it to being an organ, like a ninja, eh?