Ch. 7.3/7.4- Cartilage Growth and Bone Formation Flashcards Preview

Biology 227 Lecture > Ch. 7.3/7.4- Cartilage Growth and Bone Formation > Flashcards

Flashcards in Ch. 7.3/7.4- Cartilage Growth and Bone Formation Deck (16)
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1
Q

Appositional Growth

A

Widthwise growth of cartilage

2
Q

Interstitial Growth

A

Lengthwise growth of cartilage

3
Q

What are the steps of interstitial growth?

A

1) Chondrocyte within lacunae begins to exhibit mitotic activity.
2) Two chondroblasts are produced by mitosis from the single chondrocyte and inhabit the single lacunae.
3) Each chondroblast produces new matrix and begins separating from the other cell in the lacunae. At this stage each cell is now called a chondrocyte.
4) Cartilage continued to grow internally.

4
Q

What are the steps for appositional growth?

A

1) Mitotic activity begins within stem cells within the perichondrium.
2) New undifferentiated stems cells and committed cells that differentiate into chondroblasts are formed. Chondroblasts produce new matrix at the periphery.
3) A a result of matrix formation, the chondroblasts push apart and become chondrocytes. Chondrocyte continue to produce more matrix at the periphery.

5
Q

Ossification or osteogenesis

A

The formation and development of bone connective tissue.

6
Q

Intramembranous ossification’s other names and bones it makes…

A

Dermal ossification

flat bones of skull, facial bones, mandible, central part of clavicle.

7
Q

When does intramembranous ossification begin?

A

When mesenchyme becomes thickened and condensed with a dense supply of blood capillaries.

8
Q

What is step one of intramembranous ossification?

A

1) Ossification centers from within thick regions of mesenchyme (8 weeks of development). Some cells within the dense mesenchyme begin dividing and committed cells formed from this cell division differentiate into osteoprogenitor cells. Some osteoprogenitor cells become osteoblasts and begin secreting osteoid. Multiple ossification centers form as osteoblast increase in number.

9
Q

What is step two of intramembranous ossification?

A

Osteoid undergoes calcification. Calcium salts are deposited onto the osteoid where they crystalize. When calcification entraps osteoblasts inside lacunae inside the matrix, they become osteocytes.

10
Q

Step three of intramembranous ossification?

A

Woven bone and its surrounding periosteum form. Initially, the new formed boned is not well organized and is called woven bone (primary bone). Woven bone is replaced by lamellar bone(secondary bone). Mesenchyme that still surround woven neon begins to thicken and then organizes to form the periosteum. Mesenchyme cells grow and develop to form additional osteoblast. Newly formed blood vessels branch through this region. Calcified and intratrabecular spaces are made of spongy bone.

11
Q

Step four of intramembranous ossification?

A

Lamellar bone replaces trabeculae of woven bone. Internal and external surfaces, the spaces between trabeculae are filled to form compact bone. Internally, the trabeculae are modified slightly and produce spongy bone.

12
Q

What does endochondral ossification start with? What does it produce?

A

Endochondral ossification starts with hyaline cartilage and produces most of the bones of the skeletal system including upper and lower limbs, pelvis, vertebrae, and the ends of the clavicles.

13
Q

Step one of endochondral ossification

A
Fetal hyaline cartilage model develops.
Weeks 8-12 of development.
Chondroblast secret cartilage matrix and hyaline cartilage model.
Chondrocytes trapped in lacunae 
Perichondrium surrounds cartilage model.
14
Q

Step two of endochondral ossification

A

Cartilage calcifies and parietal bone collar forms.
In center of cartilage model, chondrocytes hypertrophy and begin to resorb some of surrounding matrix.
Cartilage matrix beings to calcify.
Chondrocytes in calcified regions die (no nutrient access)
Blood vessels grow toward cartilage while calcifying and penetrates perichondrium.
Stems cells in perichondrium divide to form osteoblasts.
Perichondrium becomes periosteum
Osteoblasts in periosteum secrete osteoid.
Osteoid hardens and becomes pariosteol bone collar around formed shaft.

15
Q

Step three of endochondral ossification

A

Woven bone and it’s surrounding periosteum form.
Initially newly formed bone is woven bone- not well formed
Woven bone (primary bone) is replaced by lamellar bone (secondary bone)
Mesenchyme around woven bone thickens and forms periosteum.
Mesenchymal cells for additional osteoblasts.
Newly formed blood vessels branch through this area.
Calcified trabecular and intratrabecular spaces are composed of spongy bone.

16
Q

Step found of endochondral ossification

A

Lamellar bone replaces compact bone as compact and spongy bone form.
Lamellar bone replaces trabeculae of woven bone.
On the internal and external surfaces, spaces between trabeculae are filled and woven bone becomes compact bone.
Internal trabeculae are modified and produce spongy bone.

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