bone growth by endochondral ossification

Question 1

The cartilage model

Answer 1

In embryo, chondrocytes lay down hyaline cartilage shaped like future bones. It calcify, the chondrocytes die off

Question 2

The bone collar

Answer 2

Osteoblasts are derived from the newly formed periosteum. Osteoblasts secrete the organic bone matrix and the matrix undergoes calcification.

Question 3

Primary ossification center

Answer 3

Blood vessels brings osteoblasts to the interior and begin to lay down spongy bones. (bone formation)

Question 4

The medullary cavity and secondary ossification sites

Answer 4

the spongy bone of the diaphysis is absorbed by osteoclasts, and the cavity created become the medullary cavity. Shortly after birth, secondary ossification centers form in the epiphyses.

Question 5

epiphyseal (growth) plate

Answer 5

a band of cartilage. remains between the primary ossification and each secondary center. The limbs keep increasing in length as et plates are still present.