CARDIAC MUSCLE CELLS IN THE RIGHT ATRIUM PRODUCE ATRIAL NATRIETIC PEPTIDE AND BRAIN NATRIURETIC PEPTIDE WHEN BLOOD VOLUME OR  BLOOD PRESSURE RISES.

 

THESE TWO HORMONES SUPPRESS THE RELEASE OF ANTIDIURETIC HORMONE AND ALDOSTERONE.  THIS CAUSES THE LOSS OF WATER AND SODIUM IONS IN THE KIDNEYS.  THIS WILL REDUCE BLOOD VOLUME AND BLOOD PRESSURE.