Interstitial Growth- Growth from within the cartilage itself.
Appositional Growth- Growth along the cartilage’s outside edge, or periphery.
Bones of the skeleton are complex, dynamic organs containing all tissue types.
The primary component is bone connective tissue, also called osseous connective tissue. They also contain connective tissue proper, cartilage connective tissue, smooth muscle tissue, fluid connective tissue, epithelial tissue, and nervous tissue.
The matrix of bone connective tissue is sturdy and rigid due to deposition of minerals in the matrix, a process called calcification.
Bones perform several basic functions: support and protection, movement, hemopoiesis, and storage of mineral and energy reserves.
Bone Functions: Support & Protection
Bone provides structural support and serve as a framework for the entire body.
They also protect many delicate tissues and organs from injury and trauma.
The rib cage protects the heart and lungs, the cranial bones enclose and protect the brain, the vertebrae enclose the spinal cord, and the pelvis cradles some digestive, urinary, and reproductive organs.
Bone Functions: Movement
Individual groups of bones serve as attachment sites for skeletal muscles, other soft tissues, and some organs.
Muscles attached to the bones of the skeleton contract and exert a pull on the skeleton which then functions as a series of levers.
The bones of the skeleton can alter the direction and magnitude of the forces generated by the skeletal muscles.
Potential movements range from powerful contractions needed for running and jumping to delicate, precise movements required to remove a splinter from the finger.
Bone Movement: Hemopoiesis
The process of blood cell production.
Blood cells are produced in a connective tissue called red bone marrow, which is located in some spongy bone.
The locations of red bone marrow differ between children and adults. In children it is located in the spongy bone, as children mature into adults, much of the red bone marrow degenerates and turns into a fatty tissue called bone marrow.
Adults have red bone marrow only in selected portions or the axial skeleton, such as the flat bones of the skull, the vertebrae, the ribs, the sternum, and the ossa coxae. Adults also have red bone marrow in the proximal epiphyses of each humerus and femur.
Bone Movement: Storage of Mineral and Energy Reserves
More than 90% of the body’s reserves of the minerals calcium and phosphate are stored and released by the bone.
Calcium is an essential mineral for such body functions as muscle contraction, blood clotting, and nerve impulse transmission.
Phosphate is needed for ATP utilization, among other things.
When calcium or phosphate is needed by the body, some bone connective tissue is broken down, and the minerals are released into the bloodstream.
Also potential energy is the form of lipids is stored in yellow bone marrow, which is located in the shafts of long bones.
Classification and Anatomy of Bones
There are four classes of bones as determined by shape: Long Bones, Short Bones, Flat Bones, and Irregular Bones.