Conceptual

Anatomy and Blood Flow of the Heart in Human Physiology [NCLEX]

The human heart functions as a four-chambered muscular pump enclosed by a pericardial sac that minimizes friction during rhythmic contractions. Blood circulation follows a closed-loop mechanism wherein deoxygenated blood traverses the right-sided tricuspid and pulmonary valves to reach the lungs, while oxygenated blood moves through left-sided bicuspid (mitral) and aortic valves into systemic arteries. The cardiac cycle operates via synchronized diastolic filling followed by systolic contraction of the atria and ventricles, regulated by semilunar and atrioventricular valves that prevent retrograde flow.