Bone Formation Reading Flashcards
(25 cards)
What are the two types of bone ossification
Intramembranous ossification
Endochondral ossification
What bones develop from Intramembranous ossification
flat bones of face
cranial bones
clavicles
begins in utero continues through adolescense
What are the steps of Intramembranous ossification
- Mesenchymal cells group into clusters and ossification center forms
- Secreted osteoid traps osteoblasts which become osteocytes
- Trabecular matrix and periosteum form
- Compact bone develops superfiscial to trabecular bone. Crowded blood vessles condense into bone marrow
What bones develop from Endochondral Ossification
Replaces hyaline cartilage
Long bones
What are the 6 steps of Endochondral Ossification
- Mesenchymal cells differentiate into chondrocytes
- Cartilage model of future bony skeleton and perichondrium form
- Capellaries penetrate cartilage.
Periochondrium transforms into periosteum.
Periosteal collar develops
Primary ossification center develops - Cartilage & Chondrocytes grow at ends of bone
- Secondary Ossification center develops
- Cartilage remains at epiphyseal plate and at joint surface as articular cartilage
What area of a bone has to do with growing in length
Epiphyseal plate
Cartilage formed hear
Diaphyseal area that carilage is ossified and diaphysis grows in length
What are the 4 zones of the Epiphyseal Plate
- Reserve Zone - closest to epiphysis
- Proliferative Zone
- Zone of maturation and hypertrophy
- Zone of Calcified Matrix - closes to diaphysis
Why is cartilage slow to heal?
a. because it eventually develops into bone
b. because it is semi-solid and flexible
c. because it does not have a blood supply
d. because endochondral ossification replaces all cartilage with bone
C. because it does not have a blood supply
Why are osteocytes spread out in bone tissue?
a. They develop from mesenchymal cells.
b. They are surrounded by osteoid.
c. They travel through the capillaries.
d. Formation of osteoid spreads out the osteoblasts that formed the ossification centers
D. Formation of osteoid spreads out the osteoblast formed the ossification centers
In endochondral ossification, what happens to the chondrocytes?
a. They develop into osteocytes.
b. They die in the calcified matrix that surrounds them and form the medullary cavity.
c. They grow and form the periosteum.
d. They group together to form the primary ossification center.
B. They die in the calcified matrix that surrounds them and form the medullary cavity
Which of the following bones is (are) formed by intramembranous ossification?
a. the metatarsals
b. the femur
c. the ribs
d. the flat bones of the cranium
D. Flat bones of cranium
Bones grow in length due to activity in the ________.
a. epiphyseal plate
b. perichondrium
c. periosteum
d. medullary cavity
A. Epiphyseal plate
Bones grow in diameter due to bone formation ________.
a. in the medullary cavity
b. beneath the periosteum
c. in the epiphyseal plate
d. within the metaphysis
B. beneath the periosteum
n what ways do intramembranous and endochondral ossification differ?
Intramembranous
* bone develops directly from sheets of mesenchymal connective tissue
* complete by the end of the adolescent growth spurt
* The flat bones of the face, most of the cranial bones, and a good deal of the clavicles (collarbones)
Endochondral
* bone develops by replacing hyaline cartilage
* lasts into young adulthood
* Long bones
Considering how a long bone develops, what are the similarities and differences between a primary and a secondary ossification center?
Primary Ossification centers
* deep in the periosteal collar
Secondary Ossification Centers
*they form later, and there are two of them, one in each epiphysis.
What is osteoid
uncalcified bone matrix secreted by osteoblasts
What is the periochondrium
membrane that covers cartilage
What is modeling
process, during bone growth, by which bone is resorbed on one surface of a bone and deposited on another
What is remodeling
process by which osteoclasts resorb old or damaged bone at the same time as and on the same surface where osteoblasts form new bone to replace that which is resorbed
What is the zone of calcified matrix
region of the epiphyseal plate closest to the diaphyseal end; functions to connect the epiphyseal plate to the diaphysis
What is the Proliferative zone
region of the epiphyseal plate that makes new chondrocytes to replace those that die at the diaphyseal end of the plate and contributes to longitudinal growth of the epiphyseal plate
What is the region of the epiphyseal plate that anchors the plate to the osseous tissue of the epiphysis
Reserve Zone
What is the region of the epiphyseal plate where chondrocytes from the proliferative zone grow and mature and contribute to the longitudinal growth of the epiphyseal plate
Zone of maturation and hypertrophy
region, deep in the periosteal collar, where bone development starts during endochondral ossification
Primary Ossification Zone
