Skeletal+System-+kat

Skeletal System (1) A bone is an organ composed of what types of tissues? (Be detailed, pictures nice) Bone is composed of fibrous and connective tissue. (2) Describe the make up of LONG bone. DESCRIBE A long one is encased by fibrous membrane (periosteum) except where it is covered at the ends by hyaline cartilage. Spongy bone beneath the cartilage may contain red blood marrow. The central shaft contains yellow bone marrow and is bordered by compact bone.

(3) What types of cells are involved in bone growth, remodeling, and repair? DESCRIBE
 * Osteoblasts**: bone forming cells. They secrete organic matrix of bone and promote the deposition of calcium salts into the matrix.
 * Osteocytes**: mature bone cells derived from osteoblasts. They maintain structure of bone.
 * Osteoclasts**: bone-absorbing cells. They break down bone and assist in depositing calcium and phosphate in the blood.

(4) What are two types of ossification. DESCRIBE.
 * Intramembranous Ossification** is ossification that forms from membranelike layers of primitive connective tissue.
 * Endochondral Ossification** is ossification that begins as hyaline cartilage that is subsequently replaced by bone tissue.
 * Ossification is the formation of bone.

(5) What are the four steps required in fracture repair? DESCRIBE. Fractures take months to repair themselves in a series of four steps.
 * 1) //Hematoma//. After a fracture, blood escapes from ruptured blood vessels and forms a hematoma (mass of clotted blood) in the spaces between the broken bone within 6-8 hours.
 * 2) //Fibrocartilaginous callus//. Tissue repair begins, and a fibrocartilaginous callus fills the space between the ends of the broken bone for about three weeks.
 * 3) //Bony callus//. Osteoblasts produce trabeculae of spongy bone and convert the fibrocartilage callus to a bony callus that joins the broken bones together and last about three to four months.
 * 4) //Remodeling//. Osteoblasts build new compact bone at the periphery, and osteoclasts absorb the spongy bone creating a new medullary cavity.

(6) What are the functions of the skeleton? The functions of the skeleton are to protect the soft parts of the body, make blood cells, supports the body, and allows our body to move. (7) How are joints classified? Joints are classified a fibrous, cartilaginous, or synovial.

(8) Give examples of different types of synovial joints and the movements they permit. Examples of **synovial** **joints** are ball-and-socket joints and hinge joints. **Ball-and-sockets joints** are located at the hips and the shoulders that allow movement in all planes, even rotational movement. **Hinge joints** are located at the knee and elbow, which permit movement in one direction only.