December 12, 2014

Journal: What is the difference between a ball and socket joint and a hinge joint?

Bone Growth

Ossification - formation of bone in the body

Bones grow longitudinally to develop height and horizontally so they can better support our weight

Cells Involved in Bone Growth Osteoprogenitor cells Osteoblasts Osteocytes Osteoclasts

Osteoprogenitor Cells

Nonspecialized cells that can turn into other cells as needed

Found in the periosteum, endosteum, and the central canal of compact bones

Osteoblasts

Actually form the bones by secreting of calcium and other minerals that give a bone its usual characteristics

Developed from osteoprogenitor cells

Osteocytes

Mature bone cells Developed from osteoblasts

Osteoclasts

Tears down bone material and help move calcium and minerals into the blood

Bone Development

Endochondral Ossification: Shaped cartilage is replaced by bone as a child grows older

Development Before Birth Cartilage bone forms Periosteum surrounds cartilage bone and the

cartilage beings to break down Spongy bone is created by osteoblasts

Now called the primary ossification center

Compact bone begins to replace the spongy bone

Development After Birth Long bones continue to grow Secondary ossification begins with spongy

tissue forming and not breaking down Epiphyseal plate (growth plate): a thin band

of cartilage forms between ossification centers to allow for continued growthHormones control bone growthEventually growth plate becomes ossified and

growth stops

Natural Bone Deterioration As the body ages the bones and

cartilage deteriorates Total bone mass also gradually

decreases as we age as well

Osteoporosis

Disease where bone density decreases and tissues deteriorate

Causes bones to break more easily

Occurs in women four times more than men

Arthritis Inflammation of the joints Cartilage, tendons, and joints becomes

less flexible and decreases the range of motion

Scoliosis Abnormal curving of the spine which

makes it appear in a ‘c’ or ‘s’ shape instead of a straight line

Types of Bone Fractures

Hairline Fracture

Fine, fracture that does not completely break the bone

Looks like a piece of hair on X-ray

Simple Fracture Also known as a

closed fracture A break without a

puncture to the skin

Spiral Fracture

When the bone is severely twisted

Greenstick Fractures

Incomplete breaks Often occurs in

children because they have softer bones than adults

Comminuted Fracture

Bone is crushed to the point that it becomes fragmented or splintered

Compound Fracture Also known as an open fracture When the bone is pushed through the skin Deep tissues have the ability to be exposed to

bacteria and infection can occur

How a Bone Heals Bone breaks and severs the blood vessels within the bone Blood leaking out of these vessels clots to form a fracture hematoma

Helps stabilize the bone and line it up for mending Bone dies without blood and dead cells are removed Fracture hematoma develops tougher tissue and becomes a soft callus Fibroblasts produce collagen which strengthens the soft callus Osteoblasts produce bone cells which form a bone callus Osteoclasts and osteoblasts work together to replace bone callus with

harder compact bone