All Correct Answers
Compact bones: Osteons - Answer- - surrounds the canal are concentric lamellae
- between the lamellae are small spaces called lacunae which contain osteocytes
- lacunae are tiny canaliculi filled with extracellular fluid
- canaliculi connect lacunae, forming a system of interconnected canals
--provides routes for nutrients & oxygen to reach the osteocytes
Bone is richly supplied with - Answer- Vessels
- periosteal vessels
- endosteal vessels
- epiphyseal vessels
- nutrient vessels
Nerves accompany blood & lympathic vessel that supply bones
Ossification - Answer- process of bone formation
- occurs during the sixth week of embryonic development
bone formations occurs in 4 situtations - Answer- 1. formation of bone in an embryo
2. growth of bones until adulthood
3. remodeling of bone
4. repair of fractures
Bone in Embryo - Answer- begins with cartilage or collagen formation
Bone formation: Intramembranous ossification - Answer- from collagens
- flat bones of the skull, mandible, maxilla, pelvis, & clavicle are formed this way
- 'soft spot' helps fetal skull pass through birth canal & later become ossified
Bone formation: Endochondral ossification - Answer- from cartilage
- replacement of a cartilage model by bone
- most bone are formed this way, including long bones
epiphyseal plate - Answer- - Growth plate
- made of cartilage
- gradually ossifies
growth in length - Answer- - cartilage continually grows
- is replaced by bone
, epiphyseal line - Answer- remnant of the epiphyseal plate, seen in adult bones
Growth in thickness - Answer- Bones grow in thickness at the outer surface
remodeling of bone - Answer- - Bone forms before birth and continually renews itself
- The ongoing replacement of old bone tissue by new bone tissue
- Old bone is continually destroyed and new bone is formed in its place throughout an
individual's life
Normal bone metabolism depends on several factors: - Answer- 1. Minerals
- large amounts of calcium and phosphorus and smaller amounts of magnesium,
fluroide, and manganese are required for bone growth and remodeling
2. Vitamins
- Vitamin A stimulates activity of osteoblasts
- Vitamin C needed for synthesis of collagen
- Vitamin D helps build bone by increasing the absorptions of calcium from foods
- Vitamins K & B12 needed for synthesis of bone proteins
3. Hormones
- Estrogen & Testosterone
- Parathyroid hormones (PTH), Calcitriol, & Calcitonin
open (compound) fracture - Answer- broken bone penetrates through the skin
closed (simple) fracture - Answer- break that does not penetrate the skin
comminuted fracture - Answer- fracture in which the bone is splintered or crushed into
pieces
greenstick fracture - Answer- one in which the bone is bent and only partially broken
impacted fracture - Answer- broken bone ends are forced into each other
Pott's fracture - Answer- fracture of the fibula, with injury of the tibial articulation
Colles fracture - Answer- fracture of the distal radius at the wrist
stress fracture - Answer- a small crack in the bone that often develops from chronic,
excessive impact
repair of bone fractures - Answer- 1. hematoma forms
- blood leaks from the torn end of blood vessels & clotted mass of blood forms around
the site
2. fibrocartilage callus forms
- fibroblasts invade the fracture site & produce collagen fibers
3. bony callus forms