Question

The diagram given below represents the human heart in one phase of its functional activities. Study the same and answer the questions that follow:

(i) Name the phase.
(ii) Label the parts 1, 2 and 3
(iii) Which part of the heart is contracting in this phase ? Give a reason to support your answer.

Answer 1

(i) Atrial systole.
(ii)
(1) Left pulmonary artery
(2) Superior vena cava
(3) Aorta.
(iii) Simultaneous contraction of both the auricles. Because the cuspid valves are open, allowing blood to flow into ventricles.