Chapter 6 bone tissue Flashcards
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
.
a) Support
b) Protection
e) Assistance in movement
f) Mineral homeostasis
g) Blood cell production
j) Triglyceride storage
Which region of a long bone articulates with other bones?
a) Diaphysis
b) Epiphysis
c) Proximal metaphysis
d) Epiphyseal plate
e) Distal metaphysis
b) Epiphysis
The shaft of a long bone is the
a) diaphysis.
b) epiphysis.
c) metaphysis.
d) periosteum.
e) medullary cavity.
a) diaphysis.
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
d) Articular cartilage
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
e) Epiphyseal plate
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
c) Metaphysis
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
a) Periosteum
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
b) Osteoclasts, osteoprogenitor cells, osteoblasts, osteocytes
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.
d) osteoblasts.
) 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.
b) osteoclasts.
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
c) Osteocytes
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
d) Canaliculi
) 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.
c) Parallel to the length of the diaphysis; the shaft resists bending even when stresses are applied
in certain directions.
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 1: a
Answer 2: b
Answer 3: c
Answer 4: d
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.
b) Osteoblasts are more active and osteoclast maintain normal activity when there is mechanical
stress placed on bones.
Briefly describe the steps in bone deposition
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.
) Briefly describe the steps in bone resorption.
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.
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
c) Calcium and phosphorous
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
d) a,b,c,d
In endochondral ossification, what is the original source of osteoblasts?
a) Endoderm
b) Mesenchyme
c) Mucus connective tissue
d) Osteoprogenitor cells
e) Ectoderm
d) Osteoprogenitor cells
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
d) Greenstick
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
e) Stress fracture
Bone mass reduction is promoted by which hormone?
a) Calcitriol
b) Calcitonin
c) Human growth hormone
d) Parathyroid hormone
e) Insulin
d) Parathyroid hormone
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
b) Parathyroid
Describe the steps in bone repair.
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.
Briefly describe the processes by which bone increases in length and diameter.
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.
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.
: 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.
Which hormone is the MOST important for Ca2+ regulation?
a) Parathyroid hormone
b) Calcitriol
c) Thyroid hormone
d) Calcitonin
e) Aldosterone
a) Parathyroid hormone
PTH will increase activity while Calcitonin will decrease activity.
a) osteoblast; osteoclast
b) osteoclast; osteoblast
c) osteoblast; osteoblast
d) osteoclast; osteoclast
d) osteoclast; osteoclast
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
e) Fracture hematoma, fibrocartilaginous callus formation, bony callus formation, bone
remodeling
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
b) estrogen; osteoclast activity
Briefly, explain how blood calcium level is regulated.
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
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.
a) The bone becomes stiff and brittle
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
Briefly describe the major differences between compact and spongy bone
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.
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
a) Ossification center develops > Calcification > Formation of trabeculae > Development of new
periosteum
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.
d) mesenchyme.
If bone is analogous to a bank, calcium is analogous to .
a) deposits
b) withdrawals
c) money
d) bank teller
e) automatic teller machine
c) money
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
e) Sex hormones
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
d) 1, 3, 4
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
a
b
c
e
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.
a) Their bones contain higher amounts of collagen.
Answer 1: Paget’s disease
Proliferation of osteoclasts, which leads to rapid bone remodeling, and weakening
the bones.
Paget’s disease
Bone fails to calcify when remodeled.
Answer 3: Osteomalacia
Bacterial infection causing inflammation, pain and rigid muscles.
Answer 4: Osteomyelitis
Bone cancer primarily affecting osteoblasts.
Answer 5: Osteosarcoma
Severe bone density loss
Osteoporosis
the receptors, respond to low blood calcium levels.
PT gland cells
input activates the control center when blood calcium is low.
Cyclic AMP
is/are the effector(s) of PTH.
Osteoclasts and kidney cells
Osteoclasts [dropdown 4] in response to PTH.
Release calcium to enter blood
The kidney [dropdown 5] in response to PTH.
Increases reabsorption of calcium
is secreted in response to PTH’s effects on the kidney.
Calcitriol
is an increase in blood calcium levels
Hypercalcemia
respond when there is an increase in blood calcium levels
Parafollicular cells
is the output in response to high blood calcium levels
Calcitonin
In response to the output when blood calcium levels are high, a(n) [dropdown 4] in bone
deposition occurs
increase
In response to the output when the blood calcium levels are high, there is a decrease in
[dropdown 5] activity
Osteoclast
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.
a) Blood calcium levels increase when bone breaks down, and decreases when bone is built.
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
a) 1, 5, 6, 7, 9
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
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
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
b) A, E, B, D, C
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 1: decreases
Answer 2: osteoblasts
Answer 3: increase
Answer 4: increase
Answer 5: demineralizes
Answer 6: osteopenia
Mechanical stress [dropdown 1] osteoblast activity in bone, and removal of mechanical stress
[dropdown 2] osteoblast activity in bone.
increases
Decrease
