The two pathways operate as a linked cycle. Pulmonary circulation carries blood between the heart and lungs, where gas exchange occurs, while systemic circulation sends oxygenated blood to tissues and returns blood containing carbon dioxide and metabolic waste to the heart. Their coordination allows oxygen delivery and waste removal to continue throughout the body.
Arteries carry blood outward from the heart, capillaries provide the vascular pathway associated with delivery and exchange at tissues, and veins return blood toward the heart. Together, these vessel types support the movement of oxygen, nutrients, carbon dioxide, and metabolic waste through the systemic pathway and complete the return of blood for continued circulation.
Tissue perfusion reflects whether circulating blood is reaching body tissues sufficiently to support oxygen and nutrient delivery. Reduced or impaired perfusion can signal difficulty maintaining organ oxygenation, even when circulation is considered as a whole. Clinically, assessing perfusion alongside blood flow helps evaluate cardiovascular function and identify possible vascular or circulatory problems.
Clinical assessment can include checking the pulse, measuring blood pressure, evaluating blood flow, and examining tissue perfusion. These observations provide complementary information about cardiovascular function and the movement of blood through the vascular system. Used together, they help clinicians recognize abnormal circulation, follow changes over time, and support decisions about further evaluation or care.
Pulse assessment provides a clinical indication of cardiac-driven blood movement, while blood pressure measurements describe pressure within the circulating system. Interpreted with blood flow and tissue perfusion findings, these measures help evaluate cardiovascular function rather than relying on one observation alone. They can also support recognition of hypertension and other circulation-related abnormalities.
Assessment is particularly relevant when clinicians suspect hypertension, vascular obstruction, or impaired organ oxygenation. Monitoring pulse, blood pressure, blood flow, and tissue perfusion can help identify these problems and track cardiovascular status during care. The resulting information supports diagnosis, treatment planning, and ongoing monitoring of cardiovascular disease.