Bone formation

Question 1

Lamellated bone

Answer 1

is in spongy bone trabeculae. Bone’s lamellae are more or less parallel to each other

Question 2

Concentric lamellae (Haversian systems)

Answer 2

Characteristic of compact bone. highly organized

Question 3

Intramembranous ossification

Answer 3

takes place in membrane of mesenchyme

Question 4

Endochondral ossification

Answer 4

takes place in hyaline cartilage

Question 5

Difference of collagen fibers in primary and secondary bone

Answer 5

Primary has randomly arranged collagen fibers. Secondary has parallel collagen fibers

Question 6

What are osteoids laid down by

Answer 6

osteoblasts

Question 7

Basics of bone formation

Answer 7

1) primary bone is first formed by osteoblasts, which lay down osteoid
2) Osteoclasts come in to break down the bone
3) secondary bone is made by osteoblasts
4) Osteoid becomes mineralized

Question 8

How do we get blood to bone

Answer 8

Bone forms around blood vessels

Question 9

Intramembranous Ossification

Answer 9

-Bone forms directly within a membrane of highly bascular mesnchyme.
Flat bones form this way

Question 10

Steps of Intramembranous Ossification

Answer 10

1) mesenchymal cells
2) osteoprogenitor cells
3) Osteoblasts
4) osteoid

Question 11

Endochondral ossification

Answer 11

bone forms in hyaline cartilage model

how long bones are formed

Question 12

Hyaline cartilage model

Answer 12

1) miniature version of bone to be is made of hyaline cartilage
2) grow interstitially and appositionally
3) perichondrium becomes vascularized and cells differentiate into osteoprogenitor cells
4) Osteoprogenitor cells start synthesizing bone matrix and perichondrium converts into a periosteum
5) osteogenic bud grows. Osteoblasts come in and degrade inside of calcified cartilage matrix
6) primary and secondary center of ossification

Question 13

Mnemonic for cartilage

Answer 13

C (calcification)
D (death)
E (erosion)
R (replaced

Question 14

Secondary center of ossification

Answer 14

forms after birth

bone forms at epiphysis but no bone collar is formed.

Question 15

Hyaline cartilage persists where

Answer 15

articular surfaces of bone

epiphyseal (growth) plates

Question 16

How does hyaline cartilage grow at articular cartilage

Answer 16

interstitial growth only - no perichondrium, so you can’t have appositional growth

Question 17

Zone of reserve cartilage

Answer 17

consists of hyaline cartilage

mitosis still takes place, but not much

Question 18

Zone of proliferation

Answer 18

Lots of mitosis taking place here. Lays down matrix

Chondrocytes look like a stack of pennies

Question 19

Zone of maturation

Answer 19

interstitial growth is occuring here

Question 20

Zone of hypertrophy

Answer 20

looks swollen because they accumulate glycogen and vacuoles
No addition of new cells here
Release of alkaline phosphatase. Calcification of hyaline cartilage matrix occurs here

Question 21

Zone of calcified cartilage

Answer 21

hyaline cartilage remnant

Question 22

Zone of resportion and ossification

Answer 22

Osteoblasts lay down osteoid

Question 23

Alkaline phosphatase

Answer 23

causes increase in phosphate conc, and even more of an increase in calcium ion conc

Question 24

Matrix vesicles

Answer 24

membrane bubbles that are released into matrix. Stimulated by osteoblasts

Question 25

Bone repair

Answer 25

Clean up debris with neutrophiles and macrophages

form new connective tissue