Answer:
B. lungs where blood picks up oxygen and returns to the left side of the heart.
Explanation:
In Human anatomy, cardiac cycle can be defined as a complete heartbeat of the human heart which comprises of sequential alternating contraction and relaxation of the atria and ventricles, therefore causing blood to flow unidirectionally (one direction) throughout the human body.
Generally, the cardiac cycle occurs in two (2) stages;
1. Diastole : in this stage, the ventricles is relaxed and would be filled with blood.
2. Systole: at this stage, the muscles contracts and thus, allow blood to be pushed through the atria.
The cardiovascular system comprises of two circulatory paths:
I. Pulmonary circulation.
II. Systemic circulation.
Pulmonary circulation transports deoxygenated blood from the right side of the heart to the lungs where blood picks up oxygen and returns to the left side of the heart.
The pulmonary circulation loop is mainly supported (powered) by the right atrium and right ventricle.
Additionally, the right atrioventricular valve (AV) also referred to as the tricuspid valve is located on the right dorsal side of the human heart. The right atrioventricular valve (AV) comprises of three (3) leaflets (flaps) which opens and closes in order to allow for the flow of blood from the right atrium of the human heart to the right ventricle. Also, the right atrioventricular valve is saddled with the responsibility of preventing blood from flowing backward in the mammalian heart.
