Science Olympiad 2021 Anatomy and Physiology | The Skeletal System

Functions of Skeletal System

1. Supports and provides shape to the body.

2. Protects internal organs.

3. Moves with the muscles.

4. Stores minerals and lipids.

5. Produces blood cells.

Skeleton

Consists of 206 bones.

Axial Skeleton

80 bones. Found in the skull, vertebrae, ribs, sternum, hyoid bone

Appendicular Skeleton

126 bones. Found in half of the bones in the hands and feet.

Compact Bone

Hard outer layer of bones - has minimal gaps and spaces.

Spongy Bone

Interior filling - consists of rod-and-plate like elements that make the bone lighter, and roomer for blood vessels and marrow.

Osteoblasts

bone forming cells synthesize and secrete unmineralized ground substance and are found in areas of high metabolism within the bone

Osteocytes

mature bone cells made from osteoblasts that have made bone tissue around themselves.These cells maintain healthy bone tissue by secreting enzymes and controlling the bone mineral content; they also control the calcium release from the bone tissue to the blood.

Bone lining cells

made from osteoblasts along the surface of most bones in an adult. Bone-lining cells are thought to regulate the movement of calcium and phosphate into and out of the bone

Osteogenic cells

respond to traumas, such as fractures, by giving rise to bone-forming cells and bone destroying cells

Osteoclasts

bone absorbing cell - large cells that break down bone tissue - important to growth, healing, remodeling

Red Marrow

Function:

Forms red and white blood cells and blood platelets

Characteristics:

- Found in bone cavities.

- Replaced by yellow marrow

- Limited to spongy bone in skull, ribs, sternum, clavicles, vertebrae and pelvis

Yellow Marrow

Stores fat.

Haversian system (osteon)

the structural unit of compact bone.

Lamella

weight-bearing, column-like matrix tubes composed mainly of collagen.

Haversian

central canal - central channel containing blood vessels and nerves.

Volkmann's canals

channels lying at right angles to the central canal, connecting blood and nerve supply of the periosteum to that of the ____ canal.

Osteocytes

mature bone cells.

Lacunae

small cavities in bone that contain osteocytes.

Canaliculi

hairlike canals that connect lacunae to each other and the central canal.

Diaphysis

Tubular shafts formed at the axis of long bones. Consists of compact bone surrounding the medullary cavity.

Epiphyses

Expanded ends of long bones

Exterior Epiphyses

compact bone

Interior Epiphyses

spongy bone.

Articular (hyaline cartilage

Joint surface covering.

Epiphyseal line

Separates the diaphysis from epiphysis.

Periosteum

A double-layered protective membrane.

Dense Regular CT

Outer fibrous layer

Endosteum

Delicate membrane covering the internal surfaces of the bones.

Short, Irregular, and Flat Bones

Thin plates of periosteum-covered compact bone on the outside with endosteum-covered spongy bone (diploë) on the inside. No diaphysis or epiphysis. Contains bone marrow between trabeculae

Bulges, Depressions, Holes serve as:

(1) Joint Surfaces. (2) Conduits for blood vessels and nerves. (3) Sites for attachments of muscles, ligaments, and tendons.

Bone Repair Process

1. An injury occurs.

2. Invasion of blood vessels/generalized cells.

3. Fibroblasts develop

4. Chondrobasts develop

5. Callus forms

6. Remodeling occurs with osteoclasts.

5 Common Broken Bones

1. Clavicle

2. Arm: radius, ulna, humorous

3. Wrist

4. Hip

5. Ankle

Sprains

ligaments reinforcing a joint are stretched or torn

Cartilage Injuries

Occur when bones are forced out of alignment

Dislocations

Occur when bones are forced out of alignment

Subluxation

partial dislocation of a joint