Lymphedema (lymphoedema in British English), also known as lymphatic obstruction, is a condition of localized fluid retention and tissue swelling caused by a compromised lymphatic system, which normally returns interstitial fluid to the thoracic duct and then the bloodstream.ymphedema (lymphoedema in British English), also known as lymphatic obstruction, is a condition of localized fluid retention and tissue swelling caused by a compromised lymphatic system, which normally returns interstitial fluid to the thoracic duct and then the bloodstream.
1 A polypeptide is a single linear chain of many amino acids, held together by amide bonds. 2  A protein is one or more polypeptide (more than about 50 amino acids long).  An oligopeptide consists of only a few amino acids (between two and twenty).
Quaternary structure is a sort of structure only present in proteins with multiple polypeptides (it is the arrangement of polypeptides). This brings up an important distinction between proteins and polypeptidesâpolypeptides are the products of translation of a single mRNA transcript, while proteins may consist of 1 or several polypeptides. All polypeptides are proteins, but not all proteins are just 1 polypeptide. Hemoglobin has 4 polypeptides, for example.