Ossification and Repair

Question 1

What is Endochondral Ossification

Answer 1

ttransformation of mesenchyme into carilaginous model which is later replaced by bone

Question 2

what is intramembranous

Answer 2

transformation of mesenchyme into cartilaginous model which is later replaced by bone

Question 3

What are examples of intramembranous ossification?

Answer 3

bones of vault of the skull ~ frontal and parietal
also the manible

Question 4

what does mesenchymal cells differentiate into

Answer 4

osteoblasts

Question 5

what do the obsteblasts from mesenchymal cells do

Answer 5

begin synthesize and secrete osteoid at multi sites

Question 6

what do these entrapped cells become

Answer 6

osteocytes

Question 7

what do the mesenchymal cells go in intramembraneous ossification

Answer 7

spindle shaped mesenchymal cells migrate and aggreagte into specific areas

Question 8

what forms in the first stage of intramembraneous ossification

Answer 8

ossification centres form within thickened regions of mesenchyme

Question 9

what is the second stage of intramembraneous ossification

Answer 9

osteoid undergoes calcification

Question 10

what is the third stage of intramembraneous ossification

Answer 10

woven bone and surrounding periosteum form

Question 11

What is the fourth stage of intramembraenous ossification

Answer 11

lamellar bone replaces woven bone as compact and spongy bone forms

Question 12

what does the mesenchymal cells differetiate into what

Answer 12

chondroblasts

Question 13

what does the chondroblasts form

Answer 13

cartilage model

Question 14

what is the cartage model replced by

Answer 14

bony tissue

Question 15

what is endonchroal ossification in a nutshell

Answer 15

hyaline cartilage model of the bone to be formed

Question 16

what is enchondral ossification responsible for forming

Answer 16

short and long bones

Question 17

what does the bone collar do

Answer 17

impeds diffusion of oxygen and nutrients into underlying cartilage and promotes degenerative changes

Question 18

what does diffusion of nutrients allow

Answer 18

calification matrix

Question 19

what trimester does bony collar formation start

Answer 19

second

Question 20

what is the composition of bone at the time of birth

Answer 20

half cartilage half bone

Question 21

what is the epiphyseal plate responsible for

Answer 21

growth in length of bone and it disappears in mature adults

Question 22

what is the resting zone

Answer 22

hyaline cartilage with typical chondrocytes

Question 23

what is proliferative zone

Answer 23

rapidly dividing chondrocytes

Question 24

what is the hypertrophic cartilage zone

Answer 24

swollen chondrocytes whose cytoplasm has accumulated glycogen

Question 25

what is the calfified cartilage zone

Answer 25

loss of the chondroytes by apotosis and calfication

Question 26

what is the ossification zone

Answer 26

appearance of first bone tissue

Question 27

what are bony spicules have in endochondral ossification

Answer 27

calcified cartilage scaffold from the eipihyseal growth p,ate

Question 28

what are the four stages of bone repair

Answer 28

hematoma formation fibrocartilginous callus formation bont callus formation bone remodelling

Question 29

what happens to the blood vessels when bone fractured

Answer 29

blood vessels are disrupted and the bone cells die

Question 30

what do damaged blood vessels form

Answer 30

reduce localised hemorahe and form blood clots

Question 31

what happens to blood in the second stage of bone growth

Answer 31

are removed by marophages

Question 32

in the second stage of bone growth how is adjacent bone matrix resolved by

Answer 32

osteoplast

Question 33

what do the periosteum and enosteum do during bone growth

Answer 33

intense proliferation by producing soft callus and fibrocartilage like tissue

Question 34

what is formed in the third stage of bone growth

Answer 34

primary bone is formed by combination of endochondral and intermembraous ossification

Question 35

what does primary bone do

Answer 35

unite the extrememtied of the fractured bone

Question 36

what does primary bone look like

Answer 36

irregulary formed traceulae

Question 37

what will happen to the primary bone

Answer 37

gradually resolved and replaced by secondary bone

Question 38

what is osteoporosis

Answer 38

bone fracture easy

Question 39

what can be used to help osteoporosis

Answer 39

hormones such as calcitonin inhibits bone destruction and parathyroid hormone promotes the bone destruction.

Question 40

what is paget's disease

Answer 40

causes erosion of bone because of uncontrolled osteoclast activity

Question 41

what is osteomalacia

Answer 41

failure of osteoid to properly mineralise insufficient diet of calcium or renal dysfunction leading to excessive phosphate loss in urine