BS: Bone Development Flashcards
Bone tissue formation, also known as…
osteogenesis/ossification
When does formation of the skeleton begin? When does bone growth stop? When does bone remodeling stop?
2 months of development
adulthood (25)
lifelong
Endochondral bone starts from….
cartilage
Why is cartilage beneficial for the precursor of endochondral bone?
cartilage can accomodate mitosis
Endochondral ossification:
bone formation by replacing cartilage
Intramembranous ossification:
bone formation from fibrous membrane
T/F– There is more membrane bone that endochondral.
false, there is more endochondral
After complete endochondral ossification, where does hyaline cartilage remain?
at the articular cartilage point (ends of bone) and the epiphyseal plate
What are the 5 main steps of ossification?
- bone collar forms around diaphysis
- central cartilage in diaphysis calcifies, then develops cavities
- periosteal bud (blood vessel) invades cavities, leading to formation of spongy bone
- diaphysis elongates, and medullary cavity forms
- epiphysis ossify
Most bones formed via intramembranous ossification are […] bones.
flat
Our hands came from what fish?
lungfish
The lungfish evolved to form the […].
greererpeton (ancient lizard)
Interstitial growth causes the bone to grow…
lengthwise
Appositional growth causes the bone to increase …
thickness
What are the 5 zones within the epiphyseal plate?
- resting zone
- proliferation (growth) zone
- hypertrophic zone
- calcification zone
- ossification
What happens during epiphyseal’s second zone?
growth zone– cartilage cells undergo mitosis
What happens during epiphyseal’s third zone?
hypertrophic zone– older catilage cells enlarge
What happens during epiphyseal’s fourth zone?
calcification zone– matrix calcifies (deteriorates), cartilage cells die, blood vessels invade
Near adolescence, […] divide less often and the […] thins and is replace by […].
chondrocytes; epiphyseal line; bone
Epiphyseal plate closure occurs when?
epiphysis and diaphysis fuse
[…] initiate ossification of the bone.
osteoblasts
Bone deposition adds…
a new matrix during bone remodeling
How often is spongy and compact bone replace?
spongy– 3-4 years
compact– 10 years
When there is an imbalance of calcium, what occurs? What cells are called to regain balance?
the parathyroid gland release a parathyroid hormone (PTH)
osteoclasts degrade bone matrix and release Ca into the blood
Sustained high Ca levels can lead to the formation of…
kidney stones
Hypocalcemia causes…
Hypercalcemia causes…
hyperexcitability
non-responsiveness
What is the importance of Ca?
functions in numerous metabolic activities (muscle contraction and coagulation)
Wolf’s law states that bones…
grow/remodel in response to demands placed on them
Bend of the bone is caused by…
off center stress
Bending […] one side and […] the other.
compresses; stretches
Why is bone hollow?
compression and tension cancel each other out at the center of the bone
Where is the diaphysis is thickest?
bending stresses are the greatest
Wolfs law can explain…
- handedness
- curved bones = buckling
- trabeculae form trusses along lines of stress
- weight lifters have thick muscle attachments
- fetus and bedridden people are featureless bc no stress
Repair involves what 4 stages?
- hematoma formation
- fibrocartilaginous callus formation
- bony callus formation
- bone remodeling
Rickets results in […], soft, […] bones because bone ends are […].
bowed; weak; enlarged
What is the cause of Rickets?
vitamin D deficiency/insufficient dietary of Ca
Osteoporosis is a group of diseases in which bone […] exceeds […].
resorption; deposit
What happens to bone during osteoporosis?
matrix is normal BUT mass declines
What bones are most susceptible to osteoporosis?
spongy bone of spine and neck of femur
