Skeletal System Make no bones about it.

What do bones do for you? Support & anchor soft tissue. Movement – muscles pull on bones to move the body & its parts. Protection of soft, delicate organs. Formation of blood cells in red marrow inside of bones. Storage of energy & minerals.

Axial Appendicular

Bones

Bone Tissue Two types of bone tissue 1. Compact Bone- dense, uniform and looks smooth. 2. Spongy Bone – composed of small needlelike pieces of bone and lots of open space - allows for structure and support with little weight.

Bone Groups 1. Short bone- cube-shaped and contain mostly spongy bone - ex: wrist & ankle   2. Long Bones – longer than wide w/ a shaft and heads at both ends -mostly compact bone, contain both red and yellow marrow. - ex: femur, radius

Bone Groups 3. Flat bones – thin, flattened, usually curved - 2 thin layers of compact bone sandwiching a layer of spongy bone & red marrow. - ex: skull, ribs, sternum, scapula 4. Irregular bones – odd-shaped bones not in the other groups -ex: vertebrae & pelvis Bone Groups

Bone Anatomy Parts of Bones: Diaphysis – shaft of long bones Epiphysis – ends of long bones Periosteum – tough membrane covering bone, supplies it w/ blood vessels & nerves Bone Marrow: Red marrow – makes blood cells, found in spaces of spongy bone. Yellow marrow – stores energy (fat), found in cavity in shaft of long bones, can convert to red marrow if needed.

Compact Bone Structure Rings of mineral crystals (lamellae) Embedded with bone cells (osteocytes) Surround tubes containing blood vessels and nerves (Haversian canals)

Compact Bone Structure

Joints Fixed Pivot Saddle Semimovable

Connective Tissue Ligaments – connect bone to bone at a joint. Tendons – connect muscle to bone, allows muscle to pull on bone & move it. Cartilage – often between bones at a joint, cushions & protects the ends of bones from friction & wear. * Synovial fluid – (* NOT A TISSUE – NO CELLS) lubricates & protects ends of bones that are under pressure.

Bone Growth Ossification – cartilage converted into bone via mineralization by osteocytes. Growth (Epiphyseal) Plates produce new cartilage cells toward center of bone. Ends of bone are pushed outward, bone elongates. Ossification occurs as cartilage cells toward center of bone are converted into bone.

Bone Growth Growth of Long Bones

Bone Disorders Arthritis - Painful inflammation (swelling) of joints. Osteoarthritis – age-related, cartilage covering ends of bones gets thin & rough, bones rub together. Rheumatoid arthritis – immune system attacks joint tissue. Osteoporosis – loss of bone mass that causes bones to weaken and break easier.