Skeletal SystemProtecting your body

Skeletal System

• System of bones and cartilage protecting your body and your vital organs while producing and storing blood

Parts of Skeletal System

• Axial- center• Appendicular- appendages• Vertebral column- spine• Thoracic Cage- ribs• Pectoral girdle- shoulders• Pelvic girdle- hips

Joints- where bones connect

• Cartilaginous- bones connected by cartilage- cushions, but only allows slight movement

• Fibrous- non-moveable- thin layer connects bones

• Synovial- allows free movement- often have a meniscus to absorb shock between the joints

Examples

• Cartilaginous- lower ribs

• Fibrous- skull bones

• Synovial- knee, shoulder, hip, fingers

Types of Bone

• Bone has three main layers– Periosteum- Outer surface of

bone. Connects to ligaments and tendons

– Compact bone- makes up outer portion under periosteum. A solid hard layer

– Spongy bone- inner part of bone, matrix of material with many gaps

Types of Bone

Parts of a Bone

• Epiphysis- top and bottom of bone, where connects to other bones

• Diaphysis- the “shaft” of the bone, thinner

Bone Cells

• Osteocytes- small cells within the bone- many together make compact bone

• Osteoblasts- create bone tissue

• Osteoclasts- break down bone tissue

Marrow

• Cells active in the spongy section of the bone- – Work in making both red and

white blood cells• Yellow marrow/pink marrow

Marrow Transplant

• Donors chosen based on the receptors on cell surfaces- chosen to be as close a match as possible– Patient cells killed– Cells from donor given to

patient– Patient gets new immune

system

Bone Diseases

• Rickets• Arthritis• Spina Bifida• Bone Cysts and Spurs• Osteogenesis Imperfecta

Rickets

• Deficiency of vitamin D (with others) causes brittle formation of bones. Often characterized by bowed legs.

Arthritis

• Pain and inflammation of joints

• Often caused by excess wear over time

Spina Bifida

• Very common birth defect linked to folic acid intake of mother during pregnancy

• Baby born without closure of spinal column- spine often outside of body

Bone Cysts and Spurs

• Cyst- small fluid-filled capsule in the bone

• Spur- Small growth on bone, often at site of joint- can cause severe pain

Osteogenesis Imperfecta

• Mainly genetic dominant trait

• Causes single AA substitution resulting in poor bone formation– Leads to very weak bones

that are easily broken

Osteogenesis imperfecta posterchild