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.
Some cells have smooth ER further specialised that is dedicated to the release and reuptake of Ca2+. The most widely used example of this is the sarcoplasmic reticulum, found in muscle cells. Calcium ion release and reuptake triggers myofibril contraction and relaxation respectively in muscle [2,4,12,18].