Which of the following electrocardiogram(EKG) waves represents atrial depolarization?

Correct Answer: D

Rationale: The P wave on an ECG signifies atrial depolarization, initiating atrial contraction and subsequent ventricular filling.

Correct Answer: C

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

Correct Answer: D

Rationale: All statements about the myocardium provided here are true.

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.