Which of the following vessels do not have the ability to constrict and dilate?

Correct Answer: C

Rationale: Capillaries lack smooth muscle, so they cannot constrict or dilate like arteries, arterioles, or veins.

Correct Answer: D

Rationale: Interatrial bundles conduct impulses that stimulate contraction of the left atrium.

Correct Answer: C

Rationale: This period is ventricular relaxation (diastole), where semilunar valves close (end of systole) and atrioventricular valves open to allow passive filling, though the term here aligns with relaxation before filling begins.

Correct Answer: A

Rationale: A decrease in O2 saturation to less than 92% indicates hypoxemia, and the nurse should start supplemental O2 immediately. An increase in apical pulse rate, 1-kg weight gain, and decreases in urine output also indicate worsening heart failure and require nursing actions, but the low O2 saturation rate requires the most immediate nursing action.

Correct Answer: B

Rationale: The cardiac plexus includes parasympathetic fibers from the vagus nerve and sympathetic fibers from the sympathetic trunk.