Collagen is an important protein that can be found throughout your body. In fact, it is found in all the connective tissues in your body ranging from your skin and bones, all the way down to your organs and blood vessels. Collagen functions several different ways in your body.
Upper gastrointestinal bleeding. Upper gastrointestinal bleeding (sometimes upper GI, UGI bleed, Upper gastrointestinal hemorrhage, gastrorrhagia) is gastrointestinal bleeding in the upper gastrointestinal tract, commonly defined as bleeding arising from the esophagus, stomach, or duodenum. Blood may be observed in vomit (hematemesis) or in altered form in the stool (melena).
Bilirubin (formerly referred to as haematoidin) is the yellow breakdown product of normal heme catabolism, caused by the body's clearance of aged red blood cells which contain hemoglobin.Bilirubin is excreted in bile and urine, and elevated levels may indicate certain diseases.ilirubin consists of an open chain of four pyrrole-like rings (tetrapyrrole). In heme, these four rings are connected into a larger ring, called a porphyrin ring. Bilirubin can be conjugated with a molecule of glucuronic acid which makes it soluble in water (see below).