The functional unit of skeletal muscle is the myofibril.
Indicate whether the statement is true or false
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Question 2) Where is digestion completed?
a. stomach.
b. small intestine lumen.
c. on the brush borders of the small intestine epithelial cells.
d. colon.
e. rectum.
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Question 3) During the power stroke all of the cross bridges on myosin do not stroke in unison when pulling the actin filaments.
Indicate whether the statement is true or false
(
Question 4) Which control mechanism brings about segmentation of the terminal portion of the small intestine?
a. gastroileal reflex.
b. distention of the stomach.
c. gastrin action.
d. both (a) and (b) above,
e. all of these answers.
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Question 5) Tropomyosin covers the cross bridge binding sites on the thick filaments when a sarcomere is not contracting.
Indicate whether the statement is true or false
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Question 6) Which of the following enzymes is not secreted into the duodenal lumen?
a. aminopeptidase.
b. lipase.
c. trypsinogen.
d. procarboxypeptidase.
e. amylase.
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Question 7) Myosin is considered to be a regulatory protein because it plays an important role in the regulation of muscle contraction.
Indicate whether the statement is true or false
(
Question 8) Epithelial cells are continually being shed from the villi because
a. the intracellular enzymes digest important cellular constituents, causing the cells to disintegrate and slough.
b. the body needs a continual supply of protein derived from the digestion of these cells.
c. new cells are continually being produced in the crypts at the base of the villi and migrate upward.
d. acid entering the small intestine from the stomach constantly destroys the small intestinal lining, causing the cells to slough.
e. none of these answers.
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Question 9) The actin filaments in sarcomere contain cross bridges.
Indicate whether the statement is true or false
(
Question 10) Segmentation
a. is the primary motility in the small intestine during digestion of a meal.
b. is both mixing and propulsive.
c. refers to sequential ring-like contractions that sweep downward, creating a stripping motion that pushes the chyme forward.
d. both (a) and (b) above.
e. all of these answers.
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