What is responsible for initiating contraction of smooth muscle?
a. stimulation by motor neurons
b. inhibition of acetylcholinesterase
c. membrane potential drifting to threshold as a result of automatic changes in ion movement across the membrane
d. excitation of the gap junctions by transmitter substance
e. stimulation by the autonomic nervous system
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Question 2) Select the incorrect statement about the pancreas.
a. it has endocrine tissue.
b. it has exocrine tissue.
c. it secretes an alkaline fluid.
d. it secretes pepsinogen.
e. it secretes trypsinogen.
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Question 3) A functional syncytium
a. refers to a pair of antagonistic muscles that function together to move a joint in two opposite directions.
b. is found in both the heart and single-unit smooth muscle
c. is associated with fast twitch fibers of skeletal muscle
d. allows for cells to contract independently
e. none of the above
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Question 4) Which of the following stimulates gallbladder contraction?
a. CCK.
b. secretin.
c. sympathetic stimulation.
d. both (a) and (c) above.
e. both (b) and (c) above.
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Question 5) A functional syncytium
a. refers to a pair of antagonistic muscles that function together to move a joint in two opposite directions.
b. can be excited to contract as a unit because action potentials can be conducted from one cell to adjacent cells through gap junctions.
c. refers to the functional junction between a smooth muscle fiber and an autonomic nerve ending.
d. more than one of these.
e. none of these answers.
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Question 6) Bile salts
a. aid fat digestion.
b. aid fat absorption through micelle formation.
c. are secreted into the bile.
d. both (a) and (b) above.
e. all of these answers.
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Question 7) Single-unit smooth muscle
a. contains an abundance of gap junctions and forms functional syncytia.
b. is self-excitable.
c. is found in the walls of the digestive, reproductive, and urinary tracts and small blood vessels.
d. both contains an abundance of gap junctions and forms functional syncytia and is self-excitable.
e. all of these answers.
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Question 8) Which vein carries blood into the liver from the digestive tract structures?
a. inferior vena cava
b. superior vena cava
c. hepatic portal vein
d. hepatic vein
e. aorta
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Question 9) Multiunit smooth muscle
a. is neurogenically activated.
b. under ANS control.
c. found in the iris of the eye.
d. all of these answers.
e. none of these answers.
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Question 10) Which of the following statements concerning secretin is correct?
a. the most potent stimulus for secretin secretion is the presence of fat in the duodenum.
b. secretin stimulates pancreatic enzyme secretion.
c. secretin stimulates the secretion of bicarbonate by the pancreas
d. secretin stimulates the acinar cells.
e. it targets only the stomach
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