A 12 Bone Develop

Question 0

Why is bone resorbed?

Answer 0

• Minimize weight

- Mineral reserve

Question 1

3 triggers of bone mineralization are?

Answer 1

• Alkaline phosphatase breaks down inhibitors
• Ca+ Pi product increases
• Nucleation sites

Question 2

What are 3 facilitators of mineralization?

Answer 2

• Osteonectin (binds Ca+ and collagen I to mediate hydroxyapatite deposition)
  -TGF-B induces collagen and alkaline phosphatase expression)
• Hormones (estrogens, androgens, calcitonin) that increase osteoblastic activity.

Question 3

Osteoclasts secrete what two substances for their function?

Answer 3

• Organic acids

- Hydrolytic enzymes

Question 4

3 ingredients for endomembranous formation?

Answer 4

• osteoblasts
• Capillaries
• Matrix (from osteoblasts) calcifies

Question 5

Between bone and cartilage, which one has blasts and cytes that continue dividing to some extent?

Answer 5

Cartilage

Question 6

Between cartilage and bone, which grows both interstitially and appositionally?

Answer 6

cartilage. Bone is only appositional.

Question 7

Primary and secondary growth centers are separated by?

Answer 7

Epiphyseal (growth) plate

Question 8

Metaphysis is characterized/defined by what?

Answer 8

-Where ossification is occurring. (just “below” the epiphyseal plate)

Question 9

What 4 zones are present in epiphyseal plate?

Answer 9

• Resting
• Proliferating
• Hypertrophy
• calcification
• ossification

Question 10

What are the 3 locations of endochondral bone deposition?

Answer 10

• Periphery of bone epiphysis
• Metaphysis
• Under periosteum in diaphysis

Question 11

what 3 types of cells can originate from osteoprogenitor cells?

Answer 11

fat, osteoblast, and chondroblasts.

Question 12

all immature bone is considered compact/cancellous?

Answer 12

cancellous AKA spongy AKA trabeculated.

Question 13

what is osteoid?

Answer 13

secreted matrix of a osteoblast that has not yet been mineralized.

Question 14

what is the main component of osteoid?

Answer 14

Type 1 collagen (90% of organic)

Question 15

osteoclast are stimulated by?

Answer 15

parathyroid hormone
thyroxine
inactivity

Question 16

when does intramembranous ossification begin?

what does it form?

Answer 16

• onset= end of second month of gestation

- typical for the formation of flat bones without the per-cartilage model.

Question 17

immature reticular (woven bone is replaced by what?

Answer 17

mature lamellar bone

Question 18

tables = compact bone?

__________=spongy bone?

Answer 18

diploe

Question 19

which type of bones are formed by endochondrial ossification?

Answer 19

long bones and irregular bones.

Question 20

where does the earliest growth in a long bone occur?

Answer 20

at the perichondrium ( the perichondrium is the layer of dense CT that surrounds the cartilage of the developing bone)

Question 21

testosterone and estrogen have what affect of the growth plate of the bone?

Answer 21

testosterone and estrogen accelerate the process of growth plate fusion/decreased lengthening.

Question 22

endochondral ossification causes the bone to grow in___________? while appositional ossification causes the bone to grow in_________?

Answer 22

endochondral=length

intramembranous=width

Question 23

where do the first ossification centers occur?

Answer 23

clavicle, arms, and mandible

Question 24

what is/are rickets?

Answer 24

rickets is disorder caused by a lack of vitamin D, calcium, or phosphate. It causes weakness in the bones due to poor mineralization and leads to skeletal deformities.

Question 25

what is osteomalacia?

Answer 25

“adult rickets”lack of vitamin D, calcium, or phosphate.

Question 26

what is scurvy?

Answer 26

a vitamin C deficiency that causes decreased type 1 collagen production and weak bones.

Question 27

what is achondroplasia?

Answer 27

Caused by normal appositional growth and impaired longitudinal growth because of faulty growth plates.