Liver Function Tests And Bilirubin Biology Essay

Liver Function Tests And Bilirubin Biology wadvasThe human body is made up of various organs and oneness of the most important homeostatic organs is the colored. However, despite its very sprightly role, is mostly underemphasised and although most of its lives atomic number 18 non as regulatory as the brain, the glossinessed is involved in important processes. These include biochemical, excretory and synthetical functions, at that placefore, to detect deviations in its function, several tests must(prenominal) be carried out. These test ar referred to as Liver function tests. They provide clues on the liver function and help to evaluate the level or meat of liver vilify. Hence, they are physical exercised in the diagnosis of liver disease. And since early diagnosis and therapeutical intervention plays a large role in the treatment of liver diseases, liver function tests are important.Liver function testsThe liver is the largest visceral organ in the body. It weigh s approximately 1.3kg (3lb) in an adult (patho book ref). It has about 500 individual functions. To ensure that the liver continues to carry out these functions, there are several tests which are carried out on the liver when investigate a patient with liver disease. These tests are carried out on the bllod, for each one of them checking the amounts or levels of various constituents in the blood. Liver function tests include tests absorb cholestasis (alkaline phosphatase, gamma glutamyl transpeptidase), tests reflecting the synthetic function of the liver tests (albumin and prothrombin time),tests depiction excretion ( haematoidin, alkaline phosphatase and gamma glutamyl transpeptidase) and tests monitoring the amount of electric cell damage or liver injury (Aspartate aminotransferase and alanine aminotransferase).BilirubinThis is a discolour compound or pigment formed by the segmentation of haemoglobin. This originates from the sectionalization of worn out, old or damaged red blood cells. The aging blood cells are taken up and destroyed macrophages (Kupffer cells) of the phagocytic transcription (which are located primarily in the spleen and in the liver. During the breakdown of haemoglobin into heme and globin, the globin is further degraded to form new-fashioned proteins and the heme part forms bilverdin. In the Kupffer cells, the bilverdin is converted to bilirubin by the use of enzymes. The bilirubin is then released into the plasma where it binds to albumin and becomes an un coalesce bilirubin.The un conflate or free bilirubin enters the hepatocytes and after mixing with glucuronic acid, it becomes a conjugated bilirubin. This conjugated bilirubin is body of water soluble and hence, soluble in cheekiness, therefore if the outflow of bile is interrupted, conjugated bilirubin will affect the colour of the urine, it becomes darker. Conjugated bilirubin enters into the petty(a) intestines through the bile ducts and there, it is deconjugated in to urobilinogen by bacteria. The urobilinogin formed could either be reabsorbed into circulation by the hepatic portal vein into the liver to be re-excreted into the bile or excreted in faeces. This process is known as the enterohepatic circulation. The urobilinogen excreted in faeces or urine is oxidized to urobilin which is responsible for the colour of faeces. in that location are two tests which are carried out for bilirubin. They are direct-reacting (which is carried out for conjugated bilirubin) and indirect-reacting (which is carried out for unconjugated bilirubin). Various conditions can lead to an elevation in the amount of bilirubin in the blood, such as stoppage of the bile ducts, redundancy production of bilirubin, reduced conjugation, reduced secretion and reduced uptake by the liver. Increased levels of indirect bilirubin are usually caused by liver cell dis rear. An example is in hepatitis where the damaged biliary excretion leads to the heraldic bearing of exces s faecal urobilinogen in the urine. This gives the urine a darker colour and can be used as an indication of early cell injury. And an profit of direct bilirubin characteristically results from an obstruction which could either be located within or outside the liver (e.g.a blockage in the bile ducts or gallstones). When the bile duct is obstructed, the concentration of urinary urobilinogen reduces because the stoppage in the excretion of bile into the gut does not lead to synthesis of the faecal urobilinogen.Albumin.Albumin is a major protein which is synthesised by the liver cells and secreted into the blood. The capacity of the synthetic function of the liver can be measured with the use of albumin. The serum albumin test, therefore, is carried out in order to measure the amount of protein in the serum. Albumin has a comparatively huge half life of twenty one days, therefore, liver damage must persist (be long term) before reduced levels of serum can be noticed. Inability to mai ntain the serum levels between the reference value of 35- 50 g/L leads to a low reading of albumin, referred to as hypoalbuminaemia, which signifies threatening liver failure. Apart from liver failure, there are other conditions which can result in low serum albumin. Examples include urinary loss, hypercatabolism and withal utter(a) malnutrition.Alkaline PhosphataseAlkaline phosphatase is an isoenzyme which is present in the liver canalicular plasma membrane of hepatocytes, in the placenta, intestine and in the tusk for bone building. The normal amount of alkaline phosphates is less 100 IU/L. Increase in alkaline phosphatase is mostly due to increase in enzyme production in areas close to an obstruction and also due to the molecular weight of the biliary isoenzyme. This can be detected with the used of serum electrophoresis. Increase in alkaline phosphatase can be caused by disorders such as cholestasis within the liver (intrahepatic) or outside the live (extrahepatic), space oc cupying lesions (such as abscesses, cysts and tumours) and hepatitis. During pregnancy, the isoenzyme located in the placenta is released and the isoenzyme in the bone is also released in children and adolescents during growth. These are known as physiological increases in serum alkaline phosphatase. In disorders such as rickets, the serum alkaline phosphatase level is increase. This type of increase is called a pathological increase. And although bilirubin levels increase alongside alkaline phosphatase levels, sometimes the bilirubin value can remain normal regardless of an increased alkaline phosphatase level.Gamma Glutamyl transpeptidaseGamma-glutamyltraferse, gGT, is a glycoprotein which is found in many tissues such as the prostate, liver, intestine, pancreas, and kidneys. It has a normal range which is 20 times (1000U/L), it is considered severe and the raised ALT level can lead to severe viral hepatitis , circulatory shock and drug or toxin induced necrosis. The levels of AST and ALT are reasonably increased (2 30 times) in hepatitis (e.g. alcoholic hepatitis). An increased level of AST normally indicates acute abnormality of liver, heart and/or skeletal muscles.