Blood Proteins: Proteins that are present in blood serum, including SERUM ALBUMIN; BLOOD COAGULATION FACTORS; and many other types of proteins.Vitelline Duct: The narrow tube connecting the YOLK SAC with the midgut of the EMBRYO; persistence of all or part of it in post-fetal life produces abnormalities, of which the commonest is MECKEL DIVERTICULUM.Blood Protein DisordersSerum Albumin: A major protein in the BLOOD. It is important in maintaining the colloidal osmotic pressure and transporting large organic molecules.Hemoglobins: The oxygen-carrying proteins of ERYTHROCYTES. They are found in all vertebrates and some invertebrates. The number of globin subunits in the hemoglobin quaternary structure differs between species. Structures range from monomeric to a variety of multimeric arrangements.Blood Protein Electrophoresis: Electrophoresis applied to BLOOD PROTEINS.