WARM UP 1/30 1. What do you call the cavities that hold osteocytes? 2. What are lamellae? 3. What is the long main portion of long bone called? 4. What does calcified mean? 5. What are tiny radiating canals that bring nutrients to bone cells called? 6. From your homework – what are 5 ways that increase chances of bone fractures? 7. What are 3 ways to see a bone fracture?

NOTES Ch 6 1/30 Bone growth and strength

Grow in diameter due to 1. OSTEOCLASTS – found in endosteum * enlarge inside of medullary * enlarge inside of medullary cavity by eating away the walls cavity by eating away the walls 2. OSTEOBLASTS – found in the periosteum * add new cells to increase the outside * add new cells to increase the outside of the bone of the bone

OSSIFICATION – turning to bone RESORPTION – breaking down bone

YEARSRESULT 0-18 Ossification > Resorption Bone grow Ossification = Resorption Bone stays same 36+ Ossification < Resorption Bone becomes thinner

Grow in length due to EPIPHYSEAL PLATE Cartilage area in the epiphysis Cartilage area in the epiphysis Grows wider to make bones longer Grows wider to make bones longer Males (0-20) Females (0-18) Males (0-20) Females (0-18) Adult – epiphyseal plate calcifies Adult – epiphyseal plate calcifies * X-ray – no epiphyseal plate, then done growing (can see in bones of legs or wrists)

Add EPIPHYSEAL PLATE to #6 on your bone diagram

Amount of growth due to 1. Sex hormones – estrogen and testosterone 2. Growth hormone – produced by pituitary gland 3. Physical activity – more=growth 4. Genetics

Bone Strength Calcium makes bones strong Calcium makes bones strong Vitamin D helps your body absorb calcium Vitamin D helps your body absorb calcium If you don’t have enough calcium, it comes out of your bones and makes them weaker If you don’t have enough calcium, it comes out of your bones and makes them weaker Exercise puts pressure on bones which makes them stronger Exercise puts pressure on bones which makes them stronger

Cartilage development at the growth plate of the long bones. (A) Normal growth plate showing (B) Growth plate in dysplasia. The growth plate is disorganized and shows no region of reproducing chondrocytes.

NOTES Ch 6 Bone problems and diseases 2/2

DYSPLASIA - bone and cartilage disorders that affect the growth and development and result in short limbs. In addition to physical characteristics such as short arms and legs, people with skeletal dysplasias may have many other health-related problems, such as spine disorders; cardiac defects; ear, nose and throat problems; and neurologic disability.

ACHONDROPLASIA a hereditary skeletal disorder characterized by a unique form of dwarfism. (shortness of the extremities relative to the trunk. )

The adult height in achondroplasia is usually less than four feet. The extremities (legs, arms, fingers, toes) are very short (micromelia) relative to the trunk which is only slightly shortened. Intramembraneous ossification is not affected. The head (cranial vault) is large. The root of the nose is depressed. The skeletal deformities just noted along with normal intelligence and sexual development distinguish achondroplasia from dwarfism resulting from endocrine and nutritional deficiencies and other causes.

Vitamin D helps body to absorb Ca you eat. RICKETS–bending of bones from weight of body due to bones not hardening * during childhood * during childhood * from lack of Ca or vitamin D (sunlight) * from lack of Ca or vitamin D (sunlight)

In addition to being synthesized in the skin, vitamin D is also found in the following foods: Fatty fish Fish liver oils Fortified milk and dairy products Egg Butter

Osteoporosis Most common and severe bone disease Loss of fiber and Ca in bone Bone pain, curve of spine, break easily

Bone strength 1. Calcium amount * Ca in blood * Ca in blood * PTH released from parathyroid gland * PTH released from parathyroid gland * resorption by osteoclasts in bones * resorption by osteoclasts in bones * Ca released from the bone matrix and into the blood * Ca released from the bone matrix and into the blood 2. Exercise * exercise * exercise * pressure on bone * pressure on bone * ossification (fibers) * ossification (fibers) * Ca being stored * Ca being stored * bone strength **the opposite is also true * bone strength **the opposite is also true WARM UP 1/25 COPY THIS INFORMATION

2. Exercise * exercise * exercise * pressure on bone * pressure on bone * ossification (fibers) * ossification (fibers) * Ca being stored * Ca being stored * bone strength * bone strength ALSO true of the opposite