Bone Function & Repair

Question 1

there are 4 stages where formation of the bone occurs

Answer 1

initially in embryo & foetus
growth
remodelling
repair of fractures

Question 2

what are the two ways that bone forms

Answer 2

intramembranous ossification
endochondral ossification

Question 3

which of the two ways of bone formation is the simplest?

Answer 3

intramembranous ossification

Question 4

there are 4 steps in intramembraneous ossification what are they

Answer 4

development of an ossification centre
calcification - cells become osteocytes
formation of trabeculae
mesenchyme condenses at periphery

Question 5

what is the development of ossification centre

Answer 5

Mesenchyme cells differentiate=>
osteogenic=> osteoblasts
Osteoblasts secrete organic matrix

Question 6

what is Calcification- cells become osteocytes

Answer 6

In lacunae they extend cytoplasmic processes to each other
Deposit calcium & other mineral salts

Question 7

what is formation of trabeculae

Answer 7

it’s the spongy bone
blood vessels grow in and red marrow is formed

Question 8

what is mesenchyme condenses at the periphery step?

Answer 8

flat bones of skull and mandible are made

Question 9

what are the five stages in endochondral ossification

Answer 9

develop a cartilage model
growth
ossification proceeds inwards
osteoblasts break some of the bone down
near birth, blood vessels enter epiphysis

Question 10

what is involved in developing a cartilage model

Answer 10

mesenchyme cells crowd together in the shape of bone
chondroblasts

Question 11

what is involved in the growth step in Endochondral Ossification

Answer 11

chondroblasts secrete cartilage
Perichondrium forms on the surface
Internal chondrocytes in lacunae die and form small cavities

Question 12

what is the Ossification proceeds inward step

Answer 12

In disintegrating cartilage osteogenic cells=> osteoblasts and create a primary ossification centre
As bone forms perichondrium => periosteum
First spongy bone is formed

Question 13

what happens in the near-birth stage of Endochondral Ossification

Answer 13

the secondary centre is developed
hyaline cartilage at end
articular cartilage
prior to adulthood hyaline cartage remains in the epiphyseal plates
growth in bone length

Question 14

when does bones stop growing

Answer 14

in adolescence

Question 15

what is the proliferative zone

Answer 15

chondrocytes divide rapidly, and form columns of stacked cells parallel to the axis of the bone.

Question 16

what is hypertrophic cartilage zone

Answer 16

contains chondrocytes (and their lacunae) that have enlarged.

Question 17

what is the zone of calcification

Answer 17

chondrocytes die leaving large empty holes.
Osteoblasts and blood vessels invade the area and begin secreting bone matrix.

Question 18

where is the bone matrix bone fromed?

Answer 18

zone of ossification

Question 19

what’s included when the bone is repairing after a fracture?

Answer 19

dead tissue is removed
chondroblasts => fibrocartilage
=> spongy bone by osteoblasts
=> remodelled to compact bone

Question 20

what are the 4 types of fractures

Answer 20

partial
complete
closed (simple)
open (compound)

Question 21

what is a partial break?

Answer 21

incomplete break (crack)
- greenstick - common in children

Question 22

what is a complete fracture in a bone

Answer 22

bone-in two or more pieces
different types
Transverse,
spiral,
comminated,
vertebral compression

Question 23

what is a closed fracture

Answer 23

simple
not through the skin

Question 24

what is a open fracture

Answer 24

compound
broken ends break skin

Question 25

what are the breaks that are common in eldarly

Answer 25

transverse
spiral
comminated
vertebral compression

Question 26

what are factors which can affect bone growth

Answer 26

adequate mineral and vitamin intake
Ca, Mg, P
vitamin A, C, D

Question 27

what can cause the bone to waste away?

Answer 27

bone is reabsorbed during disuse
bed rest,
fractures in casts,
astronauts with no gravity