What is B-type natriuretic peptide (BNP)?

B-type natriuretic peptide (BNP) is indeed a hormone produced by the ventricles of the heart, specifically in response to increased intracardiac blood volume and pressure. When the heart experiences stress due to elevated blood volume, such as in heart failure, the muscle cells in the ventricles secrete BNP. Its main roles are to promote vasodilation, enhancing diuresis (increased urination), and reducing blood pressure, all of which help to alleviate the workload on the heart and manage fluid balance in the body.

This hormone plays a crucial role in the body's response to heart strain, making it a vital marker used in clinical settings to diagnose and manage heart failure. Elevated levels of BNP in the blood can indicate heart failure and help clinicians assess the severity of the condition.

Other options describe different biological molecules or processes: hormones produced by the kidneys involve the regulation of blood pressure and fluid balance, neurotransmitters are involved in transmitting signals in the nervous system, and growth factors pertain to the processes of cell growth and repair, particularly related to blood vessels. These do not accurately describe BNP's origins or functions.