During muscle contraction, the
a. contractile proteins contract.
b. contractile proteins shorten
c. A band becomes smaller
d. I band remains unchanged.
e. amount of calcium in the cytosol remains constant
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Question 2) About _________ of the filtered urea is reabsorbed as compared to __________ of glucose.
Fill in the blank(s) with correct word
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Question 3) Which molecules are involved with regulation of cross bridge attachment activity?
a. calcium ions.
b. troponin.
c. tropomyosin.
d. both (a) and (b) above.
e. all these answers.
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Question 4) Vasopressin is also known as ____________________, indicative of its effect on the kidneys.
Fill in the blank(s) with correct word
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Question 5) During contraction of skeletal muscle fibers, the
a. contractile proteins contract.
b. thin filaments slide inward toward the A band's center as a result of cycles of cross-bridge binding and bending.
c. thick and thin filaments become tightly coiled, thus shortening the sarcomere.
d. I bands slide in between the A bands.
e. lateral sacs of the sarcoplasmic reticulum shrink, pulling the Z lines closer together.
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Question 6) Of the Na+ filtered, ____________ is normally reabsorbed
Fill in the blank(s) with correct word
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Question 7) According to the sliding-filament mechanism of muscle contraction, the
a. A bands slide in closer between the I bands.
b. thin filaments slide inward toward the center of the A band.
c. Z lines slide in between the T tubules.
d. contractile proteins contract, thus shortening the sarcomere.
e. filaments slide into the lateral sacs of the sarcoplasmic reticulum.
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Question 8) ____________________ are water channels in the tubular cells of the nephron.
Fill in the blank(s) with correct word
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Question 9) A function of tropomyosin is
a. bind Ca2+.
b. form attachments with myosin cross bridges.
c. prevent myosin cross bridges from attaching to the thin filaments.
d. serve as an ATPase.
e. none of these answers.
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Question 10) On passing through the ___________ angiotensin I is converted to angiotensin II.
Fill in the blank(s) with correct word
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