ANATOMY & PHYSIOLOGY

Skeletal System
 
Protection
The skeleton protects the most important internal organs from injury. For example, cranial bones protect the brain, and the rib cage protects the heart and lungs.
 
Assistance in movement
Most skeletal muscles attach to bones; when they contract, they pull on bones to produce movement.
 
Support
The skeleton serves as the structural framework for the body by supporting soft tissues and providing attachment points for the tendons of most skeletal muscles.
 
Mineral homeostasis (storage and release)
Bone tissue makes up about 18% of the weight of the human body. It stores several minerals, especially calcium and phosphorus, which contribute to the strength of bone. Bone tissue stores about 99% of the body’s calcium. On demand, bone releases minerals into the blood to maintain critical mineral balances (homeostasis) and to distribute the minerals to other parts of the body.
 
Blood cell production
Within certain bones, a connective tissue called red bone marrow produces red blood cells, white blood cells, and platelets. Red bone marrow consists of developing blood cells, adipocytes, fibroblasts, and macrophages within a network of reticular fibers. With increasing age, much of the bone marrow changes from red to yellow.
 
Triglyceride storage
Yellow bone marrow consists mainly of adipose cells, which store triglycerides. The stored triglycerides are a potential chemical energy reserve.