Ch 6.5 Bone development Flashcards Preview

Bio 364 Lecture Exam 1 > Ch 6.5 Bone development > Flashcards

Flashcards in Ch 6.5 Bone development Deck (22):

describe an early fetal skeleton

cartilage only with perichondrium covering everything except articular surface


what is intramembranous ossificiation?

ossificiation that begins as a membrane, not as cartilage


describe the ossification of skull bones

starts as DFCT that contains osteochondral progenitor cells
periosteum forms around outside, this contains osteoblasts
osteoblasts lay down woven bone
woven bone is resculpted into trabeculae and compact bone to form a dipole bone (compact-spongy-compact)


what is endochondral ossification?

ossification that occurs within cartilage


describe the 8 stages of endochondral ossification

1-begins as hyaline cartilage model with perichondrium
perichondrium has osteochondral progenitor cells undreneath
2-some perichondrium becomes periosteum and forms a "bone collar" around the cartilage
-cartilage model increases in L and W
3-calfied cartilage forms
4-primary ossification center forms
5-vessels enter calcified matrix, bringing osteoblasts and osteoclasts
6-more perichondrium becomes periosteum, cartilage model grows and is made into calficied bone
-osteoclasts carve marrow cavity
7-secondary ossification centers form
8-all cartilage except articular and epiphyseal plate has been converted to bone


what is the model for endochondral ossification?

hyaline cartilage model


what forms the bone collar in the endochondral ossification?

periosteum that forms from the perichondrium


does the cartilage model grow during endochondral ossification?



how does cartilage become ossified during endochondral ossification?

chondrocytes hypertrophy
matrix becomes mineralized
cells die, leaving spaces in the mineralized matrix


describe the formation of the primary ossification center during endochondral ossification

blood vessels enter the calcified matrix, bringing osteoblasts and osteoclasts
osteoblasts produce trabecular bone, making cancellous bone in the center of the bone


while the osteoclasts carve a marrow cavity, what else is happening during endochondral ossification?

more perichondrium becomes periosteum, cartilage model grows, more is calcified and made into trabecular bone


how is the marrow cavity made during endochondral ossification?

osteoclasts carve it in the center of the trabecular bone


where do secondary ossification centers appear?

in both epiphyses


how does the secondary ossification center's development differ from that of the primary ossification center?

no marrow cavity is carved out


approximately how long, after full term birth, do the secondary ossification centers form?

1 month


at what point in endochondral ossification has all cartilage (with exceptions) been converted to bone.

after the secondary ossification centers have been ossified


which cartilage areas remain cartilage in a toddler or adolescent?

articular cartilage and epiphyseal plates


what does the epiphyseal plate become when bone is mature?

epiphyseal line


describe the epiphyseal line

no hyaline cartilage, all bone


which cartilage areas remain in mature bone?

no hyaline cartilage at all
perichondrium has become the periosteum
only cartilage is articular


in what type of bone is cancellous and compact bone fully developed from calcified cartilage and woven bone?

mature bone


cartilage --> _______ --> woven bone --> _______

cartilage --> CALCIFIED CARTILAGE --> woven bone --> SPONGY BONE