The correct option is 4: Regulation of respiratory rate The Atrial Natriuretic Factor (ANF), also known as Atrial Natriuretic Peptide (ANP), is a peptide hormone secreted by the muscle cells of the heart's atria, primarily in response to atrial stretching caused by increased blood volume and elevated blood pressure. Its core function is to act as a counter-regulatory system to lower blood pressure and restore fluid and electrolyte balance within…Read More