The skeletal System functions

The skeletal system gives ____________________ and ____________________ to the body . Without the skeletal components , we would appear as big " blobs " inefficiently " oozing " around on the ground . Besides contributing to ____________________ and ____________________ , our bones perform several other functions and play an important role in ____________________ .
Bones provide a rigid ____________________ that supports the soft organs of the body . Bones support the body against the pull of gravity , and the large bones of the limbs support the trunk when standing .
The skeleton protects the soft body parts , The fused bones of the cranium surround the brain to make it less vulnerable to injury . The ____________________ surround and ____________________ the ____________________ cord . the bones of the rib cage help protect the ____________________ and ____________________ in the thorax .

Bones provide sites for ____________________ attachment . Bones and muscles work ____________________ to as simple mechanical lever systems to produce body ____________________ . A mechanical lever system has four components : a rigid bar , a pivot or fulcrum , an object or weight that is moved , and a force that supplies the mechanical energy for the movement . In the body , bones are the rigid ____________________ , the joints between the bones are the ____________________ , the body or part of it is the ____________________ that is moved , and the muscles supply the ____________________ .
The intercellular matrix of bone contains large amounts of calcium salts , the most important being calcium phosphate . ____________________ is necessary for vital metabolic process . When blood calcium levels decrease below normal , calcium is released from the ____________________ so that there will be an adequate supply for metabolic needs . When blood calcium levels are increased , the excess calcium is stored in the bone's ____________________ . Storage and release are dynamic processes that go on almost continually . Bone tissue contains lesser amounts of other inorganic ions such as sodium , magnesium , potassium and carbonate . Fat is stored in the ____________________ bone ____________________ .

Blood cell formation , called ____________________ , takes place mostly in the ____________________ bone ____________________ of bones . Red marrow is found in the cavities of most bones in an ____________________ . With age , it is largely replaced by ____________________ ____________________ for fat ____________________ . In the adult , red marrow is limited to the ____________________ bone in the skull , ribs , sternum , clavicles , vertebrae , and pelvis . Red marrow functions in the formation of erythrocytes , leukocytes , and thrombocytes