Bone

Question 1

Function of bone

Answer 1

support/protect, produce RBCs, facilitation of movement, storage of minerals

Question 2

Three structural components of bone

Answer 2

Diaphysis, Metaphysis and Epiphysis

Question 3

where is spongy bone located

Answer 3

epiphysis

Question 4

where is red bone marrow

Answer 4

the spongy bone

Question 5

where is yellow bone marrow

Answer 5

the diaphysis or the shaft of the bone

Question 6

Composition of bone

Answer 6

Extracellular matrix and cells

Question 7

Bone cells

Answer 7

fibroblasts, osteoblasts, osteocytes, osteoclasts, osteogenic

Question 8

fibroblasts

Answer 8

produce collagen and other components of the ECM

Question 9

osteoblasts

Answer 9

form new bone, synthesize and secrete the collagen matrix and calcium salts
located in the epiphyseal plate, endosteum and periosteum

Question 10

osteocytes

Answer 10

lo longer forming bone cells there just maintain the mineral concentration, these are entrapped in the matrix

Question 11

osteoclasts

Answer 11

actually “eat” the osteocytes, to reabsorb bone

are found on bone surfaces and at injury sites

Question 12

Osteogenic Cells

Answer 12

differentiate into osteoblasts

located in the deep periosteum and the bone marrow

Question 13

types of bone

Answer 13

cortical and cancellous

Question 14

what are the thin plates in the spongy bone

what is the function of them?

Answer 14

trabeculae; to distribute contact stresses and absorb dynamic loads
the arrangement of them show how the stress is applied

Question 15

What does it mean that trabeculae is anistropic?

Answer 15

the bone withstands force in different directions but not all the same amount. The bone will be stronger in some directions than others

Question 16

periosteum

Answer 16

outer fibrous layer

contains nerves, blood vessels and lymph, encases the endosteum so tendons and ligaments attach here, thinner

Question 17

endosteum

Answer 17

contains the central canals and surrounds the bone marrow

Question 18

Woven bone

Answer 18

collagen fibers are irregularly arranged to form a pattern of alternating coarse and fine fibers
FOUND IN NEWBORNS OR CALLUSES

Question 19

Lamellar Bone

Answer 19

mature bone; makes up most of the adult skeleton

Question 20

Osteogenic layer

Answer 20

the innermost layer
contains fibroblasts, stem cells and osteoblasts
decreased healing here
sharpeys fibers connect to the deeper layers of bone

Question 21

Compact bone and blood supply

Answer 21

vessels run up/down through the Haversian canals or central canals

Question 22

Cancellous bone and blood flow

Answer 22

blood vessels in the periosteum and blood in the marrow cavities
has very good blood supply

Question 23

Types of loads that occur on bone

Answer 23

tension, compression, shear, torsion and combined loading

Question 24

what type of force is bone the most capable of resisting

Answer 24

compression

Question 25

Wolff's Law

Answer 25

Bone remodels in response to external stresses, weight bearing and muscular tension

Question 26

Cortical bone is ____ than cancellous bone (looser or stiffer)

Answer 26

stiffer

Question 27

cortical bone can withstand more ___ than cancellous bone but less ____ than cancellous bone

Answer 27

stress, strain

Question 28

before failing, cancellous bone can sustain ____ % strain

Answer 28

75% strain

Question 29

Cancellous bone stress and strain

Answer 29

LOW STRESS HIGH STRAIN

Question 30

Cortical bone stress and strain

Answer 30

HIGH STRESS LOW STRAIN | fails if strain is >2%

Question 31

High loads over a short time will produce

Answer 31

high stress, low stiffness and greater load before fracture

Question 32

low loads over long periods of time will produce

Answer 32

not as stiff or strong, fractures under lower loads, HIGH STRAIN

Question 33

What happens when bone is immobilized

Answer 33

the bone is reabsorbed but not produced there is decreased collagen synthesis and mineral content (regional osteopenia) and weakened connections of tendons and ligaments

Question 34

cancellous bone healing

Answer 34

there is little or no callus formation | healing occurs through direct osteoblastic activity

Question 35

Cortical bone healing steps

Answer 35

1. inflammation 2. soft callus (blood clot replaced by fibrous tissue/cartilage) 3. hard callus (woven bone deposited on both sides of fracture site, eventually forms a collar around the bone) 4. remodeling of bone until it is lamellar

Question 36

Aging effects

Answer 36

bone density starts to decline at the age of 30 post-menopausal at risk for osteoporosis due to loss of estrogen bone stiffness decreases and has a decreased load to failure

Question 37

effect of repeated loading

Answer 37

can cause permanent strain and bone failure due to less stiffness, more deformation and a lower load to failure