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.
The vasoconstrictor polypeptide hormone, angiotensin II, which is released by the action of the enzyme renin. Its precursor, angiotensin I, is inactive until acted on by the angiotensin-converting enzyme, mainly in the lungs. Angiotensin II has a powerful effect on raising the blood pressure. It binds to angiotensin receptors and constricts the circular smooth muscle of blood vessel walls.