What is the process of bone tissue formation called?
Ossification
When does the formation of the bony skeleton start?
2nd month of development
True or False: Bone remodeling and repair occurs throughout the lifetime
True
True or False: Postnatal bone growth occurs until early adulthood
True
What are the types of ossification?
Endochondral, intramembranous
During what type of ossification do bones form by replacing cartilage, and forms most of the skeleton?
Endochondral
During what type of ossification do bones develop from fibrous membrane, forming flat bones like the clavicle and cranial bones?
Intramembranous
What type of ossification requires the breakdown of hyaline cartilage prior to ossification?
Endochondral
Where does endochondral ossification begin?
At the primary ossification center in the center of the bone shaft
During endochondral ossification, what invades the cavities in the diaphysis, forming spongy bone?
Periosteal bud
Intramembranous ossification begins with fibrous connective tissue membranes formed by what?
Mesenchymal cells
During intramembranous ossification, lamellar bone replaces woven bone and what appears?
Red marrow
What type of postnatal bone growth increases the length of long bones?
Interstitial
What type of postnatal bone growth increases bone thickness?
Appositional
Interstitial growth requires the presence of what?
Epiphyseal cartilage
During endochondral ossification, the primary site is the __________ and the secondary site is the ___________.
diaphysis, epiphysis
When endochondral ossification is complete, hyaline cartilage only remains in the what?
Ephiphyseal plate
Which bone marking is an armlike band of bone?
Remus
What bone marking is a hole/opening in the bone?
Sinus
What bone marking is a canal-like passageway?
Meatus
What builds bones?
osteoblasts
What resorps bones?
osteoclasts
Where are the osteoblasts and osteoclasts located?
under the periosteum
True or False: At the end of interstitial growth, the epiphyseal plate becomes calcified, forming a line.
True
During appositional growth, osteoblasts and osteoclasts are constantly secreting and removing, which is called?
bone remodeling
What regulates bone growth?
growth hormone, thyroid hormone, testosterone and estrogen
Which hormone is most important in stimulating epiphyseal plate activity in infancy and childhood?
growth hormone
Which hormone modulates the activity of growth hormone and ensures proper proportions?
thyroid hormone
Which hormone promotes adolescent growth spurts and ends growth by inducing epiphyseal plate closure?
testosterone/estrogen
How often is spongy bone replaced?
3-4 years
How often is compact bone replaced?
every 10 years
Bone remodeling occurs where?
surfaces of periosteum and endosteum
What is the unmineralized band of bone matrix?
osteoid seam
What is the abrupt transition zone between osteoid seam and older mineralized bone?
calcification front
When calcium levels are too low, it results in?
hyperexcitability
When calcium levels are too high, it results in?
nonresponsiveness
Sustained high blood calcium levels, involving deposits of calcium salts in blood vessels, is called?
hypercalcemia
What hormones affect bone density?
leptin, serotonin
Which hormone is released by adipose tissue and plays a role in bone density regulation?
Leptin
Which hormone is a neurotransmitter regulating mood and sleep, is made in the gut, and is secreted into the blood after eating? Also interferes with osteoblast activity
Serotonin
What describes that bones grow or remodel in response to the demands placed on it?
Wolff's Law
What determines whether and when remodeling occurs to changing blood calcium levels?
hormonal controls
What determines where bone remodeling occurs?
mechanical stress
Fractures in youth result mostly from what?
trauma
Fractures in elderly result mostly from what?
bone thinning
In what type of fracture do the bone ends retain their normal position?
nondisplaced
In what type of fracture are bone ends out of normal alignment?
displaced
In what type of fracture are bones broken all the way through?
complete
In what type of fracture are bones NOT broken all the way through?
incomplete
In what type of fracture is the skin penetrated?
open/compound
In what type of fracture is the skin NOT penetrated?
closed/simple
In what type of fracture is the bone fragmented into three or more pieces?
comminuted
In what type of fracture is the bone crushed?
compression
In what type of fracture is there a ragged break due to excessive twisting forces applied to the bone?
spiral
In what type of fracture does the epiphysis separate from the diaphysis along the epiphyseal plate?
Epiphyseal
In what type of fracture is the broken bone portion pressed inward, common in skull fractures?
depression
In what type of fracture does the bone break incompletely, with only one side of the shaft breaking?
greenstick
During what type of reduction does the physician manipulate to the correct position?
open
During what type of reduction do surgical pins or wires secure the ends of bones?
open
What happens during the first stage of bone repair?
hematoma (clot) forms
What happens during the second stage of bone repair?
fibrocartilaginous callsu forms
What happens during the third stage of bone repair?
bony callus forms
What happens in the fourth stage of bone repair?
bone remodeling occurs
In what condition are bones poorly mineralized, calcium salts not adequate, resulting in soft weak bones and pain upon bearing weight?
Osteomalacia
What condition results in bowed legs and other bone deformities where bone ends are enlarged and abnormaly long, caused by vitamin D deficiency or insufficient dietary calcium?
rickets
What is the group of diseases where bone resorption outpaces deposit?
osteoporosis
In what condition is there excessive and haphazard bone deposit and resorption, where bone is made fast and poorly, with a high ratio of spongy bone to compact bone?
Paget's disease
What type of bone marking is a large rounded projection that may be roughened?
tuberosity
What bone marking is a narrow ridge of bone, usually prominent?
crest