Bone Formation Reading

Question 1

What are the two types of bone ossification

Answer 1

Intramembranous ossification

Endochondral ossification

Question 2

What bones develop from Intramembranous ossification

Answer 2

flat bones of face
cranial bones
clavicles
begins in utero continues through adolescense

Question 3

What are the steps of Intramembranous ossification

Answer 3

1. Mesenchymal cells group into clusters and ossification center forms
2. Secreted osteoid traps osteoblasts which become osteocytes
3. Trabecular matrix and periosteum form
4. Compact bone develops superfiscial to trabecular bone. Crowded blood vessles condense into bone marrow

Question 4

What bones develop from Endochondral Ossification

Answer 4

Replaces hyaline cartilage

Long bones

Question 5

What are the 6 steps of Endochondral Ossification

Answer 5

1. Mesenchymal cells differentiate into chondrocytes
2. Cartilage model of future bony skeleton and perichondrium form
3. Capellaries penetrate cartilage.
   Periochondrium transforms into periosteum.
   Periosteal collar develops
   Primary ossification center develops
4. Cartilage & Chondrocytes grow at ends of bone
5. Secondary Ossification center develops
6. Cartilage remains at epiphyseal plate and at joint surface as articular cartilage

Question 6

What area of a bone has to do with growing in length

Answer 6

Epiphyseal plate
Cartilage formed hear
Diaphyseal area that carilage is ossified and diaphysis grows in length

Question 7

What are the 4 zones of the Epiphyseal Plate

Answer 7

1. Reserve Zone - closest to epiphysis
2. Proliferative Zone
3. Zone of maturation and hypertrophy
4. Zone of Calcified Matrix - closes to diaphysis

Question 8

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

Answer 8

C. because it does not have a blood supply

Question 9

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

Answer 9

D. Formation of osteoid spreads out the osteoblast formed the ossification centers

Question 10

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.

Answer 10

B. They die in the calcified matrix that surrounds them and form the medullary cavity

Question 11

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

Answer 11

D. Flat bones of cranium

Question 12

Bones grow in length due to activity in the ________.

a. epiphyseal plate
b. perichondrium
c. periosteum
d. medullary cavity

Answer 12

A. Epiphyseal plate

Question 13

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

Answer 13

B. beneath the periosteum

Question 14

n what ways do intramembranous and endochondral ossification differ?

Answer 14

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

Question 15

Considering how a long bone develops, what are the similarities and differences between a primary and a secondary ossification center?

Answer 15

Primary Ossification centers
* deep in the periosteal collar
Secondary Ossification Centers
*they form later, and there are two of them, one in each epiphysis.

Question 16

What is osteoid

Answer 16

uncalcified bone matrix secreted by osteoblasts

Question 17

What is the periochondrium

Answer 17

membrane that covers cartilage

Question 18

What is modeling

Answer 18

process, during bone growth, by which bone is resorbed on one surface of a bone and deposited on another

Question 19

What is remodeling

Answer 19

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

Question 20

What is the zone of calcified matrix

Answer 20

region of the epiphyseal plate closest to the diaphyseal end; functions to connect the epiphyseal plate to the diaphysis

Question 21

What is the Proliferative zone

Answer 21

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

Question 22

What is the region of the epiphyseal plate that anchors the plate to the osseous tissue of the epiphysis

Answer 22

Reserve Zone

Question 23

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

Answer 23

Zone of maturation and hypertrophy

Question 24

region, deep in the periosteal collar, where bone development starts during endochondral ossification

Answer 24

Primary Ossification Zone

Question 25

region of bone development in the epiphyses

Answer 25

Secondary Ossification Zone