Middle School Life Science: Skin, Bones, and Muscles - The Skeletal System — Flashcards

The skeletal system is your body's central framework. It consists of bones and connective tissue, including cartilage, tendons, and ligaments. It's also called the musculoskeletal system.
Bones are the main organs of the skeletal system. In adults, the skeleton consists of 206 bones, many of them in the hands and feet. The skeletal system also includes cartilage and ligaments. Cartilage is a tough, flexible connective tissue that contains the protein collagen. It covers the ends of bones where they meet. Ligaments are bands of fibrous connective tissue. They connect bones of the skeleton and hold them together.    
Without bones, you would be a soft, wobbly pile of skin, muscles, and internal organs. Clearly, bones are needed to support and shape the body. They have several other important roles as well.    
- The skeletal system makes blood cells. Most blood cells are produced inside certain types of bones.    
- The skeletal system stores calcium and helps maintain normal levels of calcium in the blood. Bones take up and store calcium when blood levels of calcium are high. They release some of the stored calcium when blood levels of calcium are low.    
- The skeletal system works with muscles to move the body. Try to walk without bending your knees and you'll see how important the skeletal system is for movement.    
- The skeletal system protects the soft organs of the body. For example, the skull surrounds and protects the brain, and the ribs protect the heart and lungs.