Chapter 6 bone tissue

Question 1

Which of the following are functions of the skeletal system? Select all that apply.
a) Support
b) Protection
c) Thermoregulation
d) Vitamin D production
e) Assistance in movement
f) Mineral homeostasis
g) Blood cell production
h) Osmotic balance
j) Triglyceride storage
k) Communication

Answer 1

.
a) Support
b) Protection

e) Assistance in movement
f) Mineral homeostasis
g) Blood cell production

j) Triglyceride storage

Question 2

Which region of a long bone articulates with other bones?
a) Diaphysis
b) Epiphysis
c) Proximal metaphysis
d) Epiphyseal plate
e) Distal metaphysis

Answer 2

b) Epiphysis

Question 3

The shaft of a long bone is the
a) diaphysis.
b) epiphysis.
c) metaphysis.
d) periosteum.
e) medullary cavity.

Answer 3

a) diaphysis.

Question 4

The is composed of hyaline cartilage and reduces friction between bones involved
in a joint.
a) Periosteum
b) Distal epiphysis
c) Epiphyseal line
d) Articular cartilage
e) Epiphyseal plate

Answer 4

d) Articular cartilage

Question 5

The is composed of hyaline cartilage and allows the diaphysis to grow in length.
a) Periosteum
b) Distal epiphysis
c) Epiphyseal line
d) Articular cartilage
e) Epiphyseal plate

Answer 5

e) Epiphyseal plate

Question 6

The is the region of long bone that contains hyaline cartilage used for growth in
length.
a) Epiphyseal plate
b) Epiphyseal line
c) Metaphysis
d) Diaphyseal
e) Articular cartilage

Answer 6

c) Metaphysis

Question 7

What area of long bone is composed of dense irregular connective tissue and osteogenic cells?
a) Periosteum
b) Endosteum
c) Medullary cavity
d) Epiphyseal plate
e) Articular cartilage

Answer 7

a) Periosteum

Question 8

Which of following selections lists bone cells in the order from unspecialized stem cell to
highly specialized mature bone cell?
a) Osteoprogenitor cells, osteoclasts, osteocytes
b) Osteoclasts, osteoprogenitor cells, osteoblasts, osteocytes
c) Osteoprogenitor cells, osteocytes, osteoblasts
d) Osteoblasts, osteoprogenitor cells, osteocytes
e) Osteoprogenitor cells, osteoblasts, osteocytes, osteoclasts

Answer 8

b) Osteoclasts, osteoprogenitor cells, osteoblasts, osteocytes

Question 9

The cells active in fracture repair during the production of the hard (spongy bone) callus are
called
a) fibroblasts.
b) osteoclasts.
c) osteocytes.
d) osteoblasts.
e) chondroblasts.

Answer 9

d) osteoblasts.

Question 10

) Cells active when cartilage needs to be removed so new bone can be produced are called
a) osteoprogenitor cells.
b) osteoclasts.
c) osteocytes.
d) osteoblasts.
e) chondroblasts.

Answer 10

b) osteoclasts.

Question 11

These cells are active once the matrix of bone calcifies. The cells sits in a lacunae.
a) Osteoprogenitor cells
b) Osteoclasts
c) Osteocytes
d) Osteoblasts
e) Chondroblasts

Answer 11

c) Osteocytes

Question 12

What are the extracellular fluid filled extensions of the lacunae called?
a) Interosteonic (perforating) canals
b) Osteonic (Haversian) canals
c) Concentric lamellae
d) Canaliculi
e) Perforating (Sharpey’s) fibers

Answer 12

d) Canaliculi

Question 13

) How are osteons in compact bone tissue aligned? How does the osteon arrangement affect
bone strength?
a) Horizontal to the metaphysis; the epiphyseal plate resists tearing due to the arrangement of
osteons.
b) Parallel to the epiphysis; the spongy bone follows the alignment of the osteons increasing the
strength of the bone ends.
c) Parallel to the length of the diaphysis; the shaft resists bending even when stresses are applied
in certain directions.
d) Randomly between the epiphyseal plates; the random arrangement of osteons makes the shaft
strong no matter what direction the bone is stressed.
e) Parallel to the perforating canals; the osteons running adjacent to the canals protects the
vessels and nerves from becoming damaged.

Answer 13

c) Parallel to the length of the diaphysis; the shaft resists bending even when stresses are applied
in certain directions.

Question 14

14) What statements describe bone remodeling? Select all that apply.
a) It occurs throughout your lifetime.
b) It involves bone resorption.
c) It involves bone deposition.
d) It occurs at different rates at different locations.
e) It occurs at a faster rate in compact bone than spongy bone.
f) Osteoclasts and osteoblasts will be working on the same tunnel simultaneously.
g) Osteoclasts place calcium and phosphorus directly into the bloodstream.

Answer 14

Answer 1: a
Answer 2: b
Answer 3: c
Answer 4: d

Question 15

Why would running and jumping have a larger effect on bone health than walking?
a) Osteoblasts are less active and osteoclast are more active when there is mechanical stress
placed on bones.
b) Osteoblasts are more active and osteoclast maintain normal activity when there is mechanical
stress placed on bones.
c) Mechanical stress does not have an influence on osteoblast and osteoclast activity.
d) Running and jumping will prevent demineralization over time.

Answer 15

b) Osteoblasts are more active and osteoclast maintain normal activity when there is mechanical
stress placed on bones.

Question 16

Briefly describe the steps in bone deposition

Answer 16

During bone deposition, osteogenic (osteoprogenitor) cells develop into osteoblasts.
The osteoblasts secrete collagen fibers and other organic substances to begin formation of
matrix. Within the spaces between fibers, calcification occurs to form a solid matrix that
eventually surrounds the osteoblast and some extracellular fluid. The osteoblast in its new lacuna
is isolated and becomes an osteocyte. The osteocyte continues to secrete matrix but at a lower
level.

Question 17

) Briefly describe the steps in bone resorption.

Answer 17

During bone resorption, an osteoclast attaches tightly to the endosteum or periosteum
of the bone and forms a leak proof seal at the edges. Then it releases protein-digesting lysosomal
enzymes and several amino acids into the sealed pocket. The enzymes digest collagen fibers and
other organic substances while the acids dissolve the bone materials. Working together several
osteoclasts carve out a small tunnel in the old bone. The degraded bone proteins and extracellular
matrix minerals enter an osteoclast by endocytosis, cross the cell in vesicles, and undergo
exocytosis on the side opposite the ruffled border. Now in the interstitial fluid, the products of
bone resorption diffuse into nearby blood capillaries. Once a small area of bone has been
resorbed, osteoclasts depart and osteoblasts move in to rebuild bone in that area.

Question 18

Which two minerals are needed in large quantities when bones are growing?
a) Calcium and chlorine
b) Magnesium and sulfur
c) Calcium and phosphorous
d) Manganese and sulfur
e) Potassium and phosphorous

Answer 18

c) Calcium and phosphorous

Question 19

List the order of the zones in an epiphyseal plate from the diaphyseal region to the distal
epiphysis.
A: Zone of calcified cartilage
B: Zone of hypertrophic cartilage
C: Zone of proliferating cartilage
D: Zone of resting cartilage
a) a,c,d,b
b) b,a,c,d
c) a,b,d,c
d) a,b,c,d

Answer 19

d) a,b,c,d

Question 20

In endochondral ossification, what is the original source of osteoblasts?
a) Endoderm
b) Mesenchyme
c) Mucus connective tissue
d) Osteoprogenitor cells
e) Ectoderm

Answer 20

d) Osteoprogenitor cells

Question 21

Which type of fracture is considered a partial fracture and is only seen in children?
a) Open
b) Comminuted
c) Impacted
d) Greenstick
e) Stress

Answer 21

d) Greenstick

Question 22

Mary, an avid runner, was complaining that her lower leg hurt. After going to the doctor,
they did not see anything on x-rays of her tibia or fibula. The doctor ordered a bone scan and saw
tiny fissures throughout her tibia without any other tissue damage. What is Mary’s likely
diagnosis?
a) Pott fracture
b) Colles fracture
c) Impacted fracture
d) Comminuted fracture
e) Stress fracture

Answer 22

e) Stress fracture

Question 23

Bone mass reduction is promoted by which hormone?
a) Calcitriol
b) Calcitonin
c) Human growth hormone
d) Parathyroid hormone
e) Insulin

Answer 23

d) Parathyroid hormone

Question 24

What hormone(s) is/are released from the control center when the control center receives
cAMP input; also important in increasing blood calcium serum levels?
a) Calcitriol and parathyroid hormone
b) Parathyroid
c) Calcitonin
d) Parathyroid hormone and insulin-like growth factors
e) Human growth hormone and estrogen

Answer 24

b) Parathyroid

Question 25

Describe the steps in bone repair.

Answer 25

After the break in the bone occurs, blood vessels in that area are damaged and blood surrounds the fracture. The blood solidifies to form a clot, which reduces bleeding. White blood cells migrate into the area to remove bacteria and damaged cells. Osteoclasts migrate in to remove dead bone matrix. Secondly, fibroblasts migrate into the fracture to form a plate of cartilage to prevent further movement and damage at the fracture site. Thirdly, osteoblasts invade to replace the cartilage with bone matrix in the form of spongy bone. Lastly, the bone matrix will be remodeled as compact bone replaces spongy bone.

Question 26

Briefly describe the processes by which bone increases in length and diameter.

Answer 26

The only means by which bone can increase in length (interstitial growth) is by activity at the epiphyseal plate. Until full height is reached, the plate consists of layers of chondrocytes, which generate matrix that is then calcified and replaced by bone matrix secreted by osteoblasts on the diaphyseal side of the plate. Around ages 18-20 the cartilage is replaced completely by bone and no more lengthwise growth can occur. Bone increases in diameter via appositional growth as new bone matrix is laid down by osteoblasts in the periosteum.

Question 27

Jamie has a tumor of the parathyroid glands that causes a hypersecretion of PTH from these glands. Predict the effect this hypersecretion would have on the skeletal system and on the secretion of calcitonin from the thyroid gland.

Answer 27

: High levels of PTH would cause high levels of osteoclast activity, thus removing calcium from bones. Bones would become weak and soft. Excess phosphate would be lost from the kidneys. High levels of calcium ions in blood may disrupt nerve and muscle function. Calcitonin levels would probably be high, trying to restore homeostasis by increasing deposition of calcium into bone.

Question 28

Which hormone is the MOST important for Ca2+ regulation? a) Parathyroid hormone b) Calcitriol c) Thyroid hormone d) Calcitonin e) Aldosterone

Answer 28

a) Parathyroid hormone

Question 29

PTH will increase activity while Calcitonin will decrease activity. a) osteoblast; osteoclast b) osteoclast; osteoblast c) osteoblast; osteoblast d) osteoclast; osteoclast

Answer 29

d) osteoclast; osteoclast

Question 30

Which of the following is the correct sequence of steps in the repair of a bone fracture? a) Fracture hematoma, bony callus formation, fibrocartilaginous callus formation, bone remodeling b) Fibrocartilaginous callus formation, bony callus formation, fracture hematoma, bone remodeling c) Bony callus formation, fracture hematoma, fibrocartilaginous callus formation, bone remodeling d) Bone remodeling, fracture hematoma, fibrocartilaginous callus formation, bony callus formation e) Fracture hematoma, fibrocartilaginous callus formation, bony callus formation, bone remodeling

Answer 30

e) Fracture hematoma, fibrocartilaginous callus formation, bony callus formation, bone remodeling

Question 31

Osteoporosis is most common in elderly women because of the lack of , which would inhibit . a) hGH; osteoclast activity b) estrogen; osteoclast activity c) IGFs; chondrocyte activity d) PTH; osteoblast activity e) calcitonin; osteoclast activity

Answer 31

b) estrogen; osteoclast activity

Question 32

Briefly, explain how blood calcium level is regulated.

Answer 32

When blood Ca2+ levels drop, PTH is secreted from the parathyroid glands. PTH increases the activity of osteoclasts to increase bone resorption, which ultimately increases Ca2+ in blood. PTH also acts on the kidneys to prevent Ca2+ loss in the urine. PTH also stimulates the production of calcitriol, which acts on the GI tract to increase absorption of Ca2+ from the intestinal lining. When blood Ca2+ level increases, it causes the synthesis and release of calcitonin from the thyroid gland. Calcitonin, inhibits osteoclasts and stimulates osteoblastic activity to increase Ca2+ deposition into bones which promotes bone formation

Question 33

If collagen is removed from bone, what happens to the bone? a) The bone becomes stiff and brittle. b) The bone becomes soft and flexible. c) The bone shows no noticeable difference. d) The bone will break into numerous pieces.

Answer 33

a) The bone becomes stiff and brittle

Answer 34

The skeletal system is used for support for the soft tissues of the body and as attachment sites for tendons of most skeletal muscles. The skeletal system also functions in protection for the internal organs. The skeletal system assists in movement working together with the muscle system. Skeletal system aids in mineral (calcium and phosphorus) homeostasis by storing several minerals and releasing them into the bloodstream on demand. Within some bones is red bone marrow that produces blood cells. Bones also contain yellow bone marrow which is a storage site for energy in the form of triglycerides

Question 35

Briefly describe the major differences between compact and spongy bone

Answer 35

Spongy bone is light, which reduces the overall weight of a bone so that it moves more readily when pulled by a skeletal muscle. The trabeculae of spongy bone tissue support and protect the red bone marrow. Compact bone, usually found in the exterior of bone, is heavy and dense and made up of osteons. Its function is to resist breakage and provide support of the body.

Question 36

Which of the following selections correctly lists the sequence of events that occur during intramembranous ossification? a) Ossification center develops > Calcification > Formation of trabeculae > Development of new periosteum b) Calcification > Ossification center develops > Formation of trabeculae > Development of new periosteum c) Ossification center develops > Formation of trabeculae > Calcification > Development of new periosteum d) Development of new periosteum > Ossification center develops > Calcification > Formation of trabeculae e) Ossification center develops > Calcification > Development of new periosteum > Formation of trabeculae

Answer 36

a) Ossification center develops > Calcification > Formation of trabeculae > Development of new periosteum

Question 37

During endochondral ossification in a fetus, bones initially develop as a cartilage model that was formed from a) periosteum. b) endosteum. c) perichondrium. d) mesenchyme. e) mucous connective tissue.

Answer 37

d) mesenchyme.

Question 38

If bone is analogous to a bank, calcium is analogous to . a) deposits b) withdrawals c) money d) bank teller e) automatic teller machine

Answer 38

c) money

Question 39

Which of the following hormones are more important post-puberty for bone growth? a) Insulin-like growth factors b) Thyroid hormones c) Human growth hormone d) Insulin e) Sex hormones

Answer 39

e) Sex hormones

Question 40

Which of the following tissues are part of bone? 1. Epithelial tissues 2. Muscular tissues 3. Nervous tissues 4. Connective tissues a) 1, 2, 3 b) 1, 2, 4 c) 1 and 4 d) 1, 3, 4 e) 1, 2, 3, 4

Answer 40

d) 1, 3, 4

Question 41

Which of the following important body functions involve calcium? Select all that apply. a) Blood clotting b) Nervous cell stability c) Muscle cell stability d) Acting as a cofactor in some enzymatic reactions e) Being the primary cation that regulates osmotic balance in cells

Answer 41

a b c e

Question 42

Why do greenstick fractures commonly occur in children? a) Their bones contain higher amounts of collagen. b) Their bones contain higher amounts of hydroxyapatite. c) Their bones are still composed of hyaline cartilage. d) Their bones are still composed of mesenchymal tissue.

Answer 42

a) Their bones contain higher amounts of collagen.

Answer 43

Answer 1: Paget's disease

Question 44

Proliferation of osteoclasts, which leads to rapid bone remodeling, and weakening the bones.

Answer 44

Paget's disease

Question 45

Bone fails to calcify when remodeled.

Answer 45

Answer 3: Osteomalacia

Question 46

Bacterial infection causing inflammation, pain and rigid muscles.

Answer 46

Answer 4: Osteomyelitis

Question 47

Bone cancer primarily affecting osteoblasts.

Answer 47

Answer 5: Osteosarcoma

Question 48

Severe bone density loss

Answer 48

Osteoporosis

Question 49

the receptors, respond to low blood calcium levels.

Answer 49

PT gland cells

Question 50

input activates the control center when blood calcium is low.

Answer 50

Cyclic AMP

Question 51

is/are the effector(s) of PTH.

Answer 51

Osteoclasts and kidney cells

Question 52

Osteoclasts [dropdown 4] in response to PTH.

Answer 52

Release calcium to enter blood

Question 53

The kidney [dropdown 5] in response to PTH.

Answer 53

Increases reabsorption of calcium

Question 54

is secreted in response to PTH's effects on the kidney.

Answer 54

Calcitriol

Question 55

is an increase in blood calcium levels

Answer 55

Hypercalcemia

Question 56

respond when there is an increase in blood calcium levels

Answer 56

Parafollicular cells

Question 57

is the output in response to high blood calcium levels

Answer 57

Calcitonin

Question 58

In response to the output when blood calcium levels are high, a(n) [dropdown 4] in bone deposition occurs

Answer 58

increase

Question 59

In response to the output when the blood calcium levels are high, there is a decrease in [dropdown 5] activity

Answer 59

Osteoclast

Question 60

Which statement describes blood calcium levels accurately? a) Blood calcium levels increase when bone breaks down, and decreases when bone is built. b) Blood calcium levels decrease when bone breaks down, and increases when bone is built. c) Blood calcium levels remain constant regardless of whether bone is built or broken down.

Answer 60

a) Blood calcium levels increase when bone breaks down, and decreases when bone is built.

Question 61

Which statements describe spongy bone? 1. Composed of trabeculae. 2. Made up of osteons 3. Found in higher amounts in the diaphysis. 4. Found lining the superficial regions of all bones. 5. Arranged along lines of force that are encountered. 6. Gaps filled with marrow. 7. Maintains strength with light weight. 8. Has the same purpose structurally as compact bone. 9. Has lamellae, osteocytes, lacunae and canaliculi. 10. Has lamellae, osteocytes, lacunae, canaliculi, and central canals. a) 1, 5, 6, 7, 9 b) 2, 3, 4, 10 c) 1, 3, 5, 7, 9 d) 4, 6, 7, 8, 10 e) 1, 2, 4, 6, 8

Answer 61

a) 1, 5, 6, 7, 9

Question 62

What statements describe osteoblasts? Select all that apply. a) Bone resorbing cells b) Bone building cells c) Active when blood calcium levels are high d) PTH causes these cells to become more active e) Made from ~50 fused monocytes f) Differentiates from osteoprogenitor g) Stem cells h) Over activity can contribute to hypocalcemia

Answer 62

b) Bone building cells c) Active when blood calcium levels are high d) PTH causes these cells to become more active f) Differentiates from osteoprogenitor h) Over activity can contribute to hypocalcemia Answer 1: b Answer 2: c Answer 3: f Answer 4: h Answer 5: d

Question 63

Place the events of a fracture repair in order. A: A hematoma will form and will form a temporary connection between the ends of the bones. B: Fibroblasts and chondroblasts migrate from the periosteum and begin to produce fibrocartilage to connect the ends of the bones. C: Osteoclasts resorb dead portions of the new bony area, and compact bone replaces spongy bone. D: Osteoprogenitor cells differentiate into osteoblasts and produce spongy bone. E: Phagocytes and osteoclasts begin to remove dead and damaged tissue. a) A, B, E, C, D b) A, E, B, D, C c) E, A, B, D, C d) A, E, D, B, C

Answer 63

b) A, E, B, D, C

Question 64

Aging affects bone in two major ways. The tensile strength of bone decreases because osteoblasts protein synthesis is reduced. Because of this, the inorganic minerals increase in the matrix. The bones become brittle and increase their susceptibility to fracture. Bone also demineralizes (loses calcium salts), which can lead to poor ossification, known as osteopenia

Answer 64

Answer 1: decreases Answer 2: osteoblasts Answer 3: increase Answer 4: increase Answer 5: demineralizes Answer 6: osteopenia

Question 65

Mechanical stress [dropdown 1] osteoblast activity in bone, and removal of mechanical stress [dropdown 2] osteoblast activity in bone.

Answer 65

increases Decrease