If a physician hears abnormal heart sounds while examining a patient with a stethoscope, this would most likely indicate a problem with
a. the firing of the sinoatrial node.
b. the contraction of the heart muscle.
c. the function of the heart valves.
d. the electrical signal from the muscles of the ventricles.
e. the flow of blood into the atria.
C; Heart sounds accompany the opening and closing of the valves. If the valves do not close completely, blood may leak back, producing abnormal sounds. These sounds are generally produced only when blood flows around constrictions, so flow into the atria is unlikely to produce an audible sound (choice e). The electrical signals from the pacemaker (choice a) and heart muscles (choice d) are sensed using an EKG, but cannot be heard, nor can you hear the muscle contract (choice b).
You might also like to view...
Which of the following is not a common way signals are relayed between cells?
A. Contact-dependent signaling B. Autocrine signaling C. Direct intercellular signaling D. Paracrine signaling E. All of the above are ways signals are relayed between cells
Members of the __________ move via pseudopodia
a. amoebozoa b. rhizaria c. archaeplastids d. excavates e. chromalveolates
Under which mating condition is the Hardy-Weinberg principle applicable?
a. Matings are nonrandom. b. Matings between individuals are random.
c. Matings between families occur preferentially. d. Matings between individuals of different genotypes occur preferentially. e. Matings between individuals of the same genotypes occur preferentially
The transfer of genes during bacterial conjugation involves rigid, tubular appendages called
A. flagella. B. sex pili. C. periplasmic flagella (axial filaments). D. fimbriae. E. cilia.