*2.1.2 Pulmonary circulation*

This circulatory system is known as the lesser circulatory system with a lower resistance circuit [3]. Such circulation begins at the right ventricle and terminates in the left atrium [3]. At first, the right ventricular blood flows to the lungs via the pulmonary artery [24]. By means of the pulmonary capillaries, the exchange of gases takes place between the circulating blood and the lungs' alveoli [24]. Once the blood has been oxygenated, it returns to the left atrium via the pulmonary veins.

#### **2.2 Components of the cardiovascular system**

The cardiovascular system is primarily composed of—(i) heart and (ii) blood vessels (i.e. capillaries, arteries, and veins).

**Figure 1.** *Circulatory system of a heathy heart (designed with biorender).*
