Biomechanics of Skeletal Tissue

Question 1

Bones are generally made of…

Answer 1

calcium carbonate

Question 2

What percentage of calcium phosphate are bones made up of?

Answer 2

60-70% of bone weight

Question 3

Calcium phosphate functions to…

Answer 3

create stiffness of the bone and protect against compression

Question 4

What minerals aid in bone growth

Answer 4

magnesium, sodium, and fluoride; collagen also helps with flexibility

Question 5

Waters function in bone is to..

Answer 5

transports nutrients and remove waste

Question 6

characteristics of Cortical Bone

Answer 6

decreased bone porosity; stiffer/ not very deformable

Question 7

Where can cortical bone be found?

Answer 7

shafts of longs bones or outer surface of flat bones

Question 8

characteristics of Trabecular Bone

Answer 8

increased porosity; deforms easier

Question 9

Other terms for trabecular bones are…

Answer 9

cancellous/ spongy bone

Question 10

Trabecular bone can be found…

Answer 10

at the end of long bones

Question 11

Trabecular bone functions to…

Answer 11

absorb impact/ pressure/ and compression

Question 12

What is the periosteum?

Answer 12

the membrane surrounding bone

Question 13

The periosteum functions to…

Answer 13

protect the bone

Question 14

anisotropic in reference to collagen fibers means…

Answer 14

different mechanical properties in response to stress from different directions

Question 15

Which force is bone most designed to handle?

Answer 15

compression

Question 16

Which force is bone weakest under?

Answer 16

shear

Question 17

Short bones mostly function to…

Answer 17

absorb shock and decrease shear force on long bones

Question 18

Flat bones function to…

Answer 18

distribute force across bone area to lessen impact

Question 19

What are examples of short bones?

Answer 19

tarsals and carpals

Question 20

What are some examples of flat bones?

Answer 20

scapula, sternum, ribs, and skull

Question 21

Why are
“irregular” bones irregular?

Answer 21

because they have many process for muscles and ligaments to attach to

Question 22

What are some examples of irregular bones?

Answer 22

vertebrae and sacrum

Question 23

What are some examples of long bones?

Answer 23

tibia, fibula, femur, humerus, ulna, and radius

Question 24

Long bones function to…

Answer 24

hold body weight. lever system for movement

Question 25

Longitudinal growth occurs at the...

Answer 25

epiphysis of the epiphyseal plate

Question 26

Where do new bones cells form?

Answer 26

in cartilaginous discs

Question 27

cartilaginous discs are located...

Answer 27

at the end of long bones

Question 28

When are cartilaginous discs most active?

Answer 28

between 12-15 years old

Question 29

Cartilaginous discs typically close around...

Answer 29

age 18 years old; 25 years old for hip

Question 30

A fracture that spreads to the inside of a growth plate is called...

Answer 30

a Salter-Harris fracture

Question 31

Osteoblasts function to...

Answer 31

build bone in the periosteum

Question 32

osteoclasts function to...

Answer 32

reabsorb and clean out the medullary cavity

Question 33

a larger cavity in the bone provides more...

Answer 33

torsional support

Question 34

Bone modeling results in...

Answer 34

bone size and shape; modeling rate decreases after skeletal maturity

Question 35

Bone remodeling results in...

Answer 35

fine tuning of bones; 5-25% per year

Question 36

Bone remodeling functions to...

Answer 36

provide added strength to bones and removes fatigued/ damaged bone

Question 37

These sense changes in fluid through pores within bone...

Answer 37

osteocytes

Question 38

Blastic activity is caused by what?

Answer 38

osteocytes

Question 39

Bone mineral density parallels...

Answer 39

stress to the bone

Question 40

Tennis players tend to have larger...

Answer 40

radius

Question 41

Baseball players tend to have larger...

Answer 41

dominant humerus

Question 42

Athletes competing in impact sports have higher...

Answer 42

bone densities than swimmers/ non-impact

Question 43

Why do children have more pliable bones?

Answer 43

because they have large amounts of collagen in their bones

Question 44

What happens to bone brittleness as we age? Why?

Answer 44

bone brittleness increases due to loss of collagen

Question 45

Bone mineralizes until...

Answer 45

women: 25-28 men: 30-35

Question 46

At what rate doe women lose bone density and volume per year?

Answer 46

.5-1% per year until menopause

Question 47

Women can lose up to what percentage of bone density/ volume per year?

Answer 47

4% per year

Question 48

A lack of stress causes... in bone density?

Answer 48

bone atrophy; a decrease in bone mineral density

Question 49

A progressive resistance program aids to...

Answer 49

decrease the rate of bone mineral reduction

Question 50

Female Athlete Triad

Answer 50

- disordered eating - amenorrhea/ no period - bone mineral loss

Question 51

Eating disorders effect...

Answer 51

hypothalamus activity; gonadotropin releasing hormone

Question 52

eating disorder results in...

Answer 52

decreased release of luteinizing hormone in the ovary

Question 53

What percentage of female athletes are affected by eating disorders?

Answer 53

22% cheerleaders 69% dancers 65% long-distance runners

Question 54

Cessation of menstrual cycle leads to...

Answer 54

estrogen deficiency

Question 55

Estrogen deficiency leads to...

Answer 55

increased bone reabsorption; osteoclastic activity

Question 56

Female Athlete Triad can lead to what percentage of decreased bone mineral density?

Answer 56

10-20% decrease

Question 57

Female Athlete Triad predominantly affects which bones?

Answer 57

weight bearing bones; tibia, femur, vertebrae

Question 58

A bone densitometry (DEXA) scan is to...

Answer 58

assess bone density

Question 59

Stress fractures are caused by...

Answer 59

low magnitude forces repeatedly sustained

Question 60

Examples of low magnitude forces are...

Answer 60

- bending - impact - compression

Question 61

Stress fractures start...

Answer 61

in the periosteum and then into the cortical bone

Question 62

Most stress fractures are located in the...

Answer 62

tibia

Question 63

What are some causes of stress fractures?

Answer 63

- increased training intensity/ duration - not absorbing forces correctly - changes in running surface - osteoblasts can't maintain with osteoclast activity