The stimulus for the heart's rhythmic contractions comes from _________.
A. intercalated discs
B. acetylcholine
C. a neuromuscular junction
D. a pacemaker potential
Answer: D. a pacemaker potential
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The hormone that stimulates platelet formation is
A) thymosin. B) thrombopoietin. C) erythropoietin. D) colony-stimulating factor. E) endothelin.
Which of the following binds to a specific receptor and initiates a response in a cell?
A)G protein B)Ligand C)Protein kinase D)Cyclic AMP
Which of the following is/are true regarding a force couple?
A. created by equal forces on opposite sides of an axis B. created by forces acting in the same angular direction C. both A and B D. none of the above
Normally, the amount of bicarbonate ions secreted into the intestine nearly equals the amount of acid secreted by the stomach during digestion
Indicate whether the statement is true or false.