Skeletal System OBJECTIVES: Divisions of the Skeletal System Classifications of Bones Anatomy of a Bone Fractures & Surgery

Human Skeleton The human skeleton is divided into 2 groups: Axial: Bones that form the longitudinal axis of the body Appendicular: Bones of the limbs & girdles.

Bone Classification There are 206 bones in the human body. Two types of bone tissue: Compact Bone: Dense, looks smooth Spongy Bone: Composed of small, needle-like pieces.

Shapes of Bones Long Bones: Longer than they are wide Have a shaft with a head at both ends Made of mostly compact bone. Found in the limbs of the body.

Shapes of Bones Short Bones: Generally cubed-shaped Contain mostly spongy bone Found in the wrists and ankles

Shapes of Bones Flat Bones: Thin, flattened, and usually curved. Two thin layers of compact bone covering spongy bones. Found in the skull, ribs, and sternum

Shapes of Bones Irregular Bones: Bones that do not fit into the previous catergories Vertebrae and hip bones.

Structure of a Long Bone Diaphysis: Shaft (long, thin part of the bone) makes up most of the bones length. Made of compact bone. Periosteum: Fibrous connective tissue that covers the diaphysis.

Structure of a Long Bone Epiphyses: Ends of the long bone. Made of compact and spongy bone. Articular Cartilage: Slippery cartilage that covers the epiphyses. Provides a smooth surface at the joint for movement.

Structure of a Long Bone Epiphyseal Plate: Cartilage found in the epiphyses of a young, growing bone. Allow for a bone to grow. By the end of puberty the cartilage is replaced by bone making an epiphyseal line.

Bone Marrow In adults, the shaft of long bones store adipose called yellow marrow. The only place to find red marrow is in the cavities of spongy flat bones and the epiphyses of some long bones.** -The bones of most young children are made of hyaline cartilage. As you grow into an adult, the cartilage hardens into bone by a process called ossification.

Making & Destroying Bone osteoblasts: bone-forming cells (make bone) Bone Building osteoclasts: bone-destroying cells. Activated when calcium levels fall below homeostatic levels

Fractures A fracture is a break in the bone. 8 Types of Fractures: Simple Compound Comminuted

Fractures 8 Types of fractures Compression Depressed Impacted Spiral Greenstick

Surgery A fracture is treated by reduction, realignment of the broken bone ends. Closed Reduction: Bone ends are realigned by a doctor. Open Reductions: Surgery is performed and bone ends are secured by pins/wires.