bone function and repair

Question 1

Function of bone

Answer 1

Mechanical- protect important and delicate tissues and organs, provide a frame work for the overall shape of the human body, from the basis of levers involved in movement

Synthetic- haemopoiesis(holds and projects red bone marrow)

Metabolic- mineral storage (calcium and phosphorus)
fat storage yellow bone marrow
acid-base homeostasis (absorbs and releases alkali salts to help regulate blood pH)

Question 2

Intramembranous ossification has how

Answer 2

Formation of bone from the cluster of mesenchymal stem cells in center of bone (not the replacement of hyaline cartilage)

Question 3

What kind of bones do intramembranous ossification

Answer 3

Flat bones formation and the thickening of long bones

Question 4

Stage I of into membranous ossification

Answer 4

Mesenchymal cells form a tight cluster
MSC transform into osteoprogenitor cells and then into osteoblasts
osteoblasts laydown a osteoid (ECM cotaining type I collagen)

Question 5

Stage II of intramembranous ossification

Answer 5

Osteoid mineralises to form spicules (surrounded by osteoblasts and containing osteosytes)

Question 6

stage III of intramembranous ossification

Answer 6

spicules join to form trabeculae

trabecule merge to form woven bone

Question 7

stage 4 of intramembranous ossifcation

Answer 7

trabeculae replaced by the lamella of mature compact bone

Question 8

ECM contains what type of collagen

Answer 8

type I

Question 9

does cancellous bone contain Haversian and Volkmanns canals

Answer 9

No

Question 10

explain the osteocyte arrangement in immature and mature bone

Answer 10

immature bone has osteocytes in random arrangements

mature bone has osteocytes arranged in concentric lamellae of osteons

Question 11

bone strength

Answer 11

bone resist fracture - great tensile and compressive strength and a degree of flexibility
main frrce lines are through the cortical bone

Question 12

why are the main force lines through the cortical bone

Answer 12

lamellae are thought to be able to slip, relative to each other to resist fracture

Question 13

factors affecting bone stability

Answer 13

osteocyte have both osteoclast and osteoblast activity
activity of osteoblast
activity of osteoclast

Question 14

4 stages of fracture repair

Answer 14

hematoma formation
firbrocartilaginous callus formation
bony callus formation
bone remodelling

Question 15

heamatoma formation

Answer 15

break rupture blood vessels and a heamatoma forms and phagocytic cells remove dead tissue

Question 16

firbrocartilaginous callus formation

Answer 16

new blood vessels infiltrate haemotoma as firbroblasts that span the producing a fibrocartilagious callus containing osteoblasts invaded from the periosteum that begin reconstructing the bone

Question 17

Bony callus formation

Answer 17

the fibrocartilagious callus is converted to cancellous bone called a bony callus by endochondrial and intramembranous ossification

Question 18

bone remodelling

Answer 18

where cancellous bone is converted to compact bone. (especially in the cortial region)

Question 19

osteogenesis

Answer 19

mutation in COL1A gene
incorrect production of collagen 1 fiber
weak bones and increased fracture risk
shorten height and stature
mainly effects children as don't live past adulthood

Question 20

rickets

Answer 20

mainly effects children
vitamin D deficiency
poor calcium mobilidsation
ineffective mineralisation
weakened bone development
soft bone
shortened height and stature
painful to walk

characteristic bowed legs

Question 21

osteomalacia

Answer 21

rickets in children
vitamin D deficiency - low mineralisation, increased osteoid

increased calcium reabsorption
e.g protection from sunlight-produces vit D

Question 22

osteoporpsis

Answer 22

primary 
type 1 - postmenapausal women 
due to an increase in osteoclast number
loss of oestrogen after the menopause
type 2 - occurs in oldre men and women
due to the loss of osteoblast function
loss of both oestrogen and androgen

secondary
result of drug theapy
processes affect bone remodelling
metabolic bone diseases

Question 23

osteoporosis risk factors

Answer 23

insufficient calcium intake
exercise
cigarette smoking in women

Question 24

anchondroplasia

Answer 24

FGF3 mutated gene

effected endochondrial ossification affected