Final answer:
The blood travels through a complex vascular system from the veins in the lower leg to the lungs for gas exchange and then back to the heart and out to the body before returning to the leg. The cardiac cycle, regulated by the nervous system, ensures that blood is pumped effectively throughout this circuit.
Step-by-step explanation:
Pathway of Blood Through the Vascular System
The pathway of blood through the vascular system is both intricate and vital for transporting oxygen and nutrients to various parts of the body while also carrying away waste products. Starting from a vein in the lower leg, a red blood cell would travel through the venous system up to the heart, entering through the right atrium, moving to the right ventricle, then being propelled through the pulmonary artery to the lungs. In the lungs, carbon dioxide is exchanged for oxygen. Afterward, the oxygenated blood returns via the pulmonary veins to the left side of the heart, into the left atrium, down to the left ventricle, and then is pumped through the aorta. From the aorta, blood is distributed to the body through major and minor arteries, reaching further into the tissues via arterioles and capillaries. From the capillary beds, the deoxygenated blood begins its return journey via venules that coalesce into veins, leading back up the leg to complete the circuit.
Essential to the functioning of this circulatory system is the cardiac cycle, which is influenced by the nervous system through the regulation of heart rate and blood vessel dilation, thereby connecting the two systems.