Image: Seals are consumers. An ecosystem is made up of animals, plants and bacteria as well as the physical and chemical environment they live in. The living parts of an ecosystem are called factors while the environmental factors that they interact with are called abiotic factors.
Atrial natriuretic peptide (ANP), also called atrial natriuretic factor (ANF), atrial natriuretic hormone (ANH), cardionatrine, cardiodilatin (CDD), or atriopeptin, is a powerful vasodilator, and a protein (polypeptide) hormone secreted by heart muscle cells.
At rest, the atrial contraction contributes only about 10% to the total ventricular volume. If the heart rate is high and the ventricles don't have time to fill completely, atrial systole can contibute as much as 40%. Atria relaxation causes atrial pressure to be lower than ventricular pressure.