Unit 2: Bone and cartilage - Practice Quiz

1 Which mineral is the primary inorganic component of bone?

2 Which protein makes up the majority of the organic matrix of bone?

3 The dense outer layer of bone is known as:

4 The basic structural unit of compact bone is the:

5 Which canals in compact bone run longitudinally and carry blood vessels?

6 Volkmann's canals in bone primarily serve to:

7 The main artery supplying blood to the shaft of a long bone is the:

8 Bone is generally strongest when loaded in which mode?

9 On a stress–strain curve, the slope of the initial linear region represents the:

10 Stress is defined as:

11 A viscoelastic material such as bone exhibits behaviour that depends on:

12 The gradual increase in deformation of bone under a constant sustained load is called:

13 The gradual decrease in stress under a constant applied strain is known as:

14 The Maxwell model of viscoelasticity consists of a spring and a dashpot arranged:

15 In viscoelastic models, the spring element represents the:

16 The Voight (Kelvin–Voigt) model arranges a spring and a dashpot:

17 Which component gives articular cartilage its ability to resist compression by attracting water?

18 The time-dependent response of articular cartilage to loading is mainly due to:

19 Describing bone as anisotropic means that its mechanical properties:

20 Bone is often modelled as a composite material because it combines:

21 Bone is a composite material. The mineral phase (hydroxyapatite) primarily contributes which mechanical property, while the collagen phase contributes another?

22 A bone sample is decalcified (mineral removed), leaving only the organic matrix. What behavior would you expect from this sample?

23 In a long bone, blood generally flows in which predominant direction through the cortical bone during normal circulation?

24 The nutrient artery enters a long bone through the diaphysis. Which structure serves as the main channel for its passage into the cortex?

25 Cortical bone typically has an ultimate tensile strength lower than its compressive strength. Given a compressive strength of about and tensile strength of about , this indicates bone is:

26 The elastic modulus (Young's modulus) of cortical bone is approximately longitudinally. If a long specimen with cross-section is loaded with , the approximate strain is:

27 Bone is viscoelastic, meaning its mechanical response is rate-dependent. At higher strain rates (rapid loading), bone tends to become:

28 Under a constant applied stress, a viscoelastic bone specimen slowly continues to deform over time. This time-dependent behavior is called:

29 The Maxwell model consists of a spring and dashpot in series. Which viscoelastic phenomenon does it best represent?

30 In the Voigt (Kelvin–Voigt) model, a spring and dashpot are arranged in parallel. What is a key limitation of this model?

31 For a Maxwell model with spring constant and viscosity , the characteristic relaxation time is given by:

32 The time-dependent creep and stress relaxation of articular cartilage is dominated by which physical mechanism?

33 When articular cartilage is loaded and held, fluid is squeezed out and creep occurs until equilibrium. Which component provides the swelling pressure that helps resist compression?

34 Cortical bone is described as anisotropic. What does this mean for its mechanical testing?

35 Cortical bone is often modeled as transversely isotropic. How many independent elastic constants does a transversely isotropic material require?

36 Wolff's Law states that bone adapts to the loads placed upon it. Under sustained increased mechanical loading, bone typically:

37 Astronauts in microgravity experience bone loss. This observation is best explained by which principle?

38 Osteoporosis is diagnosed using DEXA scanning, which reports a T-score. Which T-score value indicates osteoporosis by WHO criteria?

39 Post-menopausal osteoporosis is largely driven by declining estrogen. The mechanism by which estrogen deficiency accelerates bone loss is:

40 Bisphosphonates are a common osteoporosis treatment. Their primary pharmacological action is to:

41 A researcher demineralizes a cortical bone sample by removing all hydroxyapatite while leaving the organic matrix intact. Which change in mechanical behavior is most consistent with this treatment?

42 In lamellar bone, adjacent lamellae have collagen fibers oriented in alternating directions. From a materials standpoint, this arrangement primarily improves which property?

43 In a long bone, the nutrient artery supplies the inner cortex while periosteal vessels supply the outer cortex. If the nutrient artery is occluded in an adult, what is the expected consequence for the diaphyseal cortex?

44 Cortical bone loaded to failure in tension versus compression along its longitudinal axis typically shows which relationship in ultimate strength?

45 A bone specimen has a stress-strain curve with Young's modulus GPa and yields at a strain of . A second identical-geometry specimen from an osteoporotic donor shows the same modulus but yields at strain . Which conclusion is best supported?

46 Bone is loaded at two different strain rates in tension. Which combination of observations correctly reflects its viscoelastic nature?

47 During a creep test, a viscoelastic bone specimen is held at constant stress. Which strain-versus-time behavior is expected?

48 For a Maxwell model (spring and dashpot in series) subjected to a suddenly applied constant strain , the stress relaxes as with . What does this predict for stress as ?

49 The Kelvin-Voigt model (spring and dashpot in parallel) is subjected to a constant stress at . Which behavior does it predict, and what is its main limitation?

50 A Maxwell element has spring constant GPa and dashpot viscosity GPa·s. After a step strain, what fraction of the initial stress remains at s?

51 In biphasic theory, the time-dependent creep of articular cartilage under constant compressive load is governed primarily by which mechanism?

52 During confined compression stress relaxation of cartilage, why does the peak stress far exceed the equilibrium stress?

53 Cortical bone is often modeled as transversely isotropic rather than fully orthotropic or isotropic. What does transverse isotropy imply about its elastic constants?

54 Treating bone as a composite of stiff hydroxyapatite reinforcement in a compliant collagen matrix, the Voigt (iso-strain) and Reuss (iso-stress) bounds give the upper and lower limits of composite modulus. Which loading assumption yields the upper bound?

55 According to Wolff's law and the mechanostat concept, a bone experiencing habitual strains within the physiological "lazy zone" (approximately 200–2500 microstrain) will most likely:

56 A patient's limb is immobilized in a cast for 8 weeks. Which combination of changes best describes the expected disuse response of the underlying bone?

57 A postmenopausal woman has a DXA-derived T-score of at the femoral neck. Using WHO criteria, how is she classified, and what does the T-score represent?

58 Bisphosphonates and teriparatide both treat osteoporosis but by opposite primary mechanisms. Which pairing is correct?

59 Why does estrogen deficiency after menopause accelerate bone loss at the cellular level?

60 Trabecular (cancellous) bone is affected earlier and more severely than cortical bone in early postmenopausal osteoporosis. What best explains this?