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1-A person who experiences a drop in plasma calcium levels will respond by:
B increasing secretion of pth that will stimulate osteoclasts
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2-In a normal healthy skeletal muscle fiber the specific event that end a contraction is
A active transport of ca back into the sr
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3-The tissue that is responsible for growth and remodeling of bone in the skeleton
E stem cells in osteogenic layer, fibroblasts of fibrous periosteum, osteoblasts in endosteum
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4-The major function of the sarcoplasmic reticulum in muscle contraction is to
B regulate intracellular caqlcium concentration
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5-Mineralized bone contains which of the following matrials that contribute to its structure?
E-all-collagen, calcium carb, hydroxyapatite
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6-Normal bone formation and growth are dependent on the adequate intake of
C calcium, phosphate and vitamin D
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7-The event that begins a contraction of sarcomeres within a skeletal muscle fiber is
C calcium binging to troponin
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8-During the later stages of the healing process for a broken bone, a patient is often allowed to use a sling or walking cast that allows some freedom of movement for the affected limb. Why?
B minor flexing of the bone speeds bone remodeling by stimulating osteoblasts
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9-The action that causes myosin heads to release from binding sites on actin is
D-Binding a fresh ATP to the myosin heads
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10-A rapidly available form of energy in skeletal muscles that is synthesized during resting periods
B creatine phosphate
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11-A resting muscle that has not been exercised for several hours shows increasingly strong contractions when stimulated again. This is called
d-treppe
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12-Which of the followimg statement is correct about osteoid?
c-is composed of glycoproteins and collagen proteins
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13-Structural adaptations of bone tissue that are important in helping bones to resist fractures are
d- a and b-cylindrical osteons, counter-rotating bands of collagen,
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14-Osteoprogenitor cells are responsible for
a-dividing to produce osteoblasts
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15-Bone remodeling is stimulated by
e-all-increased bending or twisting, weak electrical currents, increased secretion of testosterone/estrogen
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16-A young patient is experiencing skeletal growth rates that are significantly behind other children of the same age. Tests show a below normal growth hormone level so likely cause is
d-a and b, decreased mitosis of osteoblasts and decreased growth of cartilage in epiphyseal plate
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17-After being stimulated a muscle fiber increases tension until it reaches it maximum force but the load suspended from the fiber does not move this is an example of
c-isometric contraction
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18-metacarpals in the wrist grow by
d-a and b--elongation of diaphysis and conversion of cartilage to bone at the diaphyseal margin of the epi plates.
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19-Formulation of bony tissues (ossification) occurs at approx. what stage in fetal development?
c-8 weeks
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20-lactate that is produced during periods of intense muscle activity
A is converted back into pyruvate in the liver but only when aerobic conditions exist
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21=growth of bones is promoted by which?
D-a and b thyroid and testosterone/estrogen
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22-the occipital bones of the skull grow
B by intramembranous development withn flexible dense connective tissue
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23 during healing in a broken bone, binding of the broken edges together a tough but flexible form if scare tissue occurs in what stage of the process?
C fibrocartilage callus
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24 during formation of muscles in the developing fetus which of the following is true
D – a and b – groups of myoblasts fuse, skeletal muscles are present by week 8
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25 During remodeling of bone tissue minerals in the matrix must be dissolved and then soft matrix is digested. The is accomplished by
D osteoclasts
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26 in intramembranous bone growth bone tissue first appears when
b-mesenchymal cells transform into osteoblasts to form an ossification center
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27-The only step in cellular respiration that can function in the absence of oxygen is
D glycolysis
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28-the ability you have to lif an object with your arm and hold it at a fixed position is possible because of what muscle property?
A wave summation
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29 The time interval from the beginning of excitation of a skeletal muscle and the beginning of contraction is
d-both a and b, latent period, from 1 ot 3 milliseconds
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30-When pyruvate is fully decomposed in cellular respiration
e-all of energy is transferred to nadh and fadh2, process occurs in krebs cycle, co2 is produced
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31 flexion of the myosin heads, the power stroke, duringn contraction occurs when what event occurs?
D ATP is split forming adp and pi
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32 a person ingests a chemical that binds irreversibly to the ach receptors on the motor end plate but does not stimulate the sarcolemma. The consequence of this would be
A contraction only from external electrical stimulation
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33 which is the proper sequence of events leading up to the contraction of a muscle cell
B actionpotential to axon, ca enters the axon terminal, ach is released into synapse, action potential is generated on the sarcolemma, ap travels down t tubule, ca is released from SR
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34 which of the following is true or neuromusculat junctions
E all of above all junctions are simultaneous, only one junction for each fiber, an axon may have many junctions.
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35 which of the following is not correct concerning skeletal muscle fibers?
d-fibers are joined by gap junctions
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36-postural musles like the erector spinae must maintain a nearly constant state of contraction for long periods of time without fatiguing. Which of the following are ture about the composition of these and other long endurance muscles?
d-a and b-slow oxidative, high concentration of oxygen storing myoglobin
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37-which of the following will not affect the strength a skeletal muscle contraction?
B increase in myoglobin concentration
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38 when exercising aerobically below anaerobic threshold, the energy source that sustains contractions after 5 minutes is
B creatine phosphate?
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39 the protein that allows myosin to bind to actin in a skeletal muscle fiber to begin contraction is
C tropomyosin
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40 the I band of a mofibril contains which of the following
D actin contain thin filaments and z dixc proteins
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