Which of the following is a specialized tissue in the right atrium that acts as the heart's natural pacemaker by generating the electrical signal for the heartbeat?
A) Sinus Venosus
B) Sinoatrial Node
C) Atrioventricular Node
D) Septa
Answer: B) Sinoatrial Node
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The degree of stretch experienced by the sarcomeres in the ventricle cells before they contract is called:
A) preload. B) contractility. C) afterload. D) stroke volume.
Which of the following is sometimes used in diagnostic imaging?
A) a radioisotope B) a proton C) an ion D) an atom E) an electrolyte
Pupillary muscle groups are controlled by the ANS. Parasympathetic activation causes pupillary ________, and sympathetic activation causes ________
A) dilation; constriction B) dilation; dilation C) constriction; dilation D) constriction; constriction E) vasoconstriction; vasoconstriction
During muscle contraction, myosin heads attach to actin and thereby form connections called ________.
Fill in the blank(s) with the appropriate word(s).