Which of following is a function of the skeletal system? |
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blood cell production
calcium homeostasis
body support
protection of internal organs
All of the answers are correct. |
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When a fractured bone heals it leaves a thickened region known as a ____________. |
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fracture hematoma
callus
bone scab
tuberosity
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This cell (osteoclast) functions to _________. |
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lay down matrix fibers
build bone
maintain bone
break down bone
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Spongy bone is filled with ____________. |
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compact bone
red marrow
the osteons
fatty marrow
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A vertebra is an example of a(n) __________ bone. |
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dense
flat
irregular
short
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In relationship to the diaphysis of a long bone, the osteons are |
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diagonal.
radial.
anterior.
proximal.
parallel.
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A drop in blood calcium levels stimulates the secretion of __________. |
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parathyroid hormone
growth hormone
calcitonin
thyroid hormone
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A bone scan of an older patient revealed the beginnings of osteoporosis. Which of these interventions is notrecommended? |
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bed rest
vitamin D supplements
calcium supplements
vitamin C supplements
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Migration of osteoblasts into the ___________ creates the __________. |
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epiphysis, secondary ossification center
diaphysis, secondary ossification center
epiphysis, primary ossification center
diaphysis, tertiary ossification center
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Where in the body does the production of precursors for the synthesis of calcitriol occur? |
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small intestine
kidneys
bone
skin
liver
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Which of these forms by intramembranous bone formation? |
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mandible
carpal bones
humerus
long bones
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Which of these is a primary role of the skeletal system? |
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leverage
calcium homeostasis
muscle attachment site
All of these are primary roles of the skeletal system.
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Which of the following are not components of the skeletal system? |
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tendons
bones
cartilage
ligaments
other tissues that connect bones
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Which of the following characteristics applies to the cells known as osteoclasts? |
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They are stem cells.
They are mature bone cells.
The cells dissolve matrix.
The cells secrete matrix.
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Osteoblasts differentiate from __________. |
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osteocytes
osteomedullary cells
osteoclasts
osteoprogenitor cells |
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Bone is composed of ________ percent cells. |
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2
15
50
25
10
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Through the action of osteoclasts, |
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osteoid is calcified.
new bone is formed.
an organic framework is formed.
fractured bones regenerate.
bony matrix is dissolved.
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________ account(s) for almost two-thirds of the weight of bone. |
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Water
Fluoride
Calcium phosphate
Calcium carbonate
Collagen fibers
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________ cells are located in the inner cellular layer of the periosteum. |
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Osteoprogenitor
Osteoclast
Chondroblast
Osteocyte
Osteoid
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The most abundant cell type in bone is |
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osteoclasts.
osteocytes.
osteoprogenitor cells.
osteolytes.
osteoblasts.
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The type of bone that forms the diaphysis of a long bone is called __________ bone. |
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trabecular
compact
cancellous
spongy
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The interconnecting tiny arches of bone tissue found in spongy bone are called |
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trabeculae.
interstitial lamellae.
concentric lamellae.
lacunae.
osteons.
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Fat is stored within the |
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metaphysis.
medullary cavity.
spongy bone.
diaphysis.
epiphysis.
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The trabeculae of spongy bone |
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are composed mostly of cartilage
.will collapse under stress.
are organized along stress lines.
are concentrated in the cortex of the diaphysis.
are organized parallel to the long axis of the bone. |
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Migration of blood vessels into the central region of the cartilage bone model, starting bone development, occurs at which site? |
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secondary ossification center
periosteum
primary ossification center
epiphysis
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The cell (osteoblasts) designated by the arrow _________. |
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differentiates into osteoblasts
maintain bone from outside the lacuna
requires oxygen and nutrients to function
breaks down bone for calcium reabsorption
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During endochondral bone formation, the primary ossification center is located in the __________. |
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distal epiphysis
proximal epiphysis
diaphysis
metaphysis
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Intramembranous ossification begins with differentiation of ________ cells. |
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osteoprogenitor
osteocyte
osteoblast
osteoclast
mesenchymal
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When the epiphyseal plate is replaced by bone, |
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interstitial bone growth begins.
appositional bone growth begins.
long bones have reached their adult length.
puberty begins.
the bone becomes more brittle.
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Accelerated closure of the epiphyseal plates could be caused by |
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too little thyroxine.
elevated levels of estrogen.
high levels of vitamin D.
an excess of growth hormone.
too much calcium in the diet.
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When production of sex hormones increases at puberty, epiphyseal plates |
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increase slowly.
accelerate rapidly, but mostly in thickness.
are hardly affected.
get wider.
become narrower.
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In normal adult bones, |
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osteoclasts continue to be active long after osteoblast activity ceases.
a portion of the protein and mineral content is replaced each year.
exercise will have no effect on bone remodeling.
there is no turnover of minerals.
osteoblast activity exceeds osteoclast activity, once bone has been formed.
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Calcitriol is required for __________. |
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collagen synthesis
activating osteoclasts
quieting osteoblasts
absorbing dietary calcium and phosphate
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A lack of exercise could |
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result in porous and weak bones.
cause bones to lose their medullary cavity.
cause bones to become longer.
cause bones to store more calcium.
cause bones to become thicker.
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Excessive growth hormone prior to puberty could result in |
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osteoporosis.
giantism.
osteopenia.
dwarfism.
rickets.
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Which hormone increases blood calcium upon secretion? |
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parathyroid hormone (PTH)
Angiotensin converting enzyme (ACE)
thyroid hormone
growth factor
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Bone plays a central role in the regulation of blood levels of |
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sulfate.
iron.
sodium.
potassium.
calcium.
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Which of the following is formed immediately after a fracture? |
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hematoma
external callus
spongy bone
internal callus
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What is normally found at a fracture hematoma? |
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blood clot
bone fragments
dead bone
All of these are found at the site of a fracture hematoma.
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Why does osteoporosis affect more women than men? |
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Men exercise more than women and therefore have less osteoporosis.
Men do not remodel the skeleton as fast as women.
Women have a decrease in sex hormones after menopause whereas men continue to produce male sex hormones throughout adulthood.
Women typically do not get enough calcium in their diet.
Pregnancy causes deossification of bones in women and will lead to osteoporosis.
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Aging has what effect on the skeletal system? |
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fusion of joints, especially syndesmoses
loss of calcium and collagen fibers from matrix
progressive loss of processes and tuberosities
increase in the number of cranial foramina
increase in adipose tissue in epiphyses
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