Introduction to Laboratory Medicine Practice Test

Brain Natriuretic Peptide (BNP) is a hormone that's primarily released from the ventricles of the heart, particularly in response to increased wall stress and volume overload. This release typically occurs when the heart is functioning under strain, such as in conditions like heart failure. BNP has several actions, including promoting natriuresis (the excretion of sodium in urine), diuresis, and vasodilation, which help reduce the workload on the heart.

The other options—atria, septum, and aorta—do not play a significant role in the production or release of BNP. While the atria do release Atrial Natriuretic Peptide (ANP), it is specific to that part of the heart. The septum refers to the dividing wall between the left and right sides of the heart and does not synthesize BNP. The aorta is a major blood vessel that carries blood away from the heart and does not engage in hormone release. Understanding the specific sources and functions of heart hormones like BNP is crucial for interpreting their roles in cardiovascular health and disease.