Final answer:
The journey of a blood drop starting from the tricuspid valve involves passage through the heart to the lungs for oxygenation and back through the heart into systemic circulation.
Step-by-step explanation:
Following a drop of blood through the circulatory system starting at the tricuspid valve involves tracking the journey through the heart, lungs, and back to the heart. Once the blood passes through the tricuspid valve, it enters the right ventricle and is then pumped into the pulmonary artery through the pulmonary valve. The blood travels to the lungs via the pulmonary artery, where it releases carbon dioxide and gains oxygen. Oxygenated blood then returns to the heart through the pulmonary veins, entering the left atrium. From the left atrium, it flows through the mitral valve into the left ventricle, which then pumps it into the aorta. The systemic circulation begins as the aorta distributes blood to the body's organs, limbs, and tissues. Deoxygenated blood is returned to the heart from the systemic circulation through a network of veins, ultimately reaching the superior and inferior vena cava, and into the right atrium, completing the cycle.