STPM Biology - chapter 9: Revision essay question 5

5. Explain the function of the liver.

Answer


-Regulates blood and body carbohydrate level at 80-100mg/100ml of blood:
    ~Converts excess glucose into glycogen in the presence of insulin in a process called
      glycogenesis.
    ~Converts glycogen into glucose in the presence of glycagon in a process called glycogenolysis.
    ~Releases glucose into the blood when the blood glucose level drops below the normal level.
    ~Metabolise lactate(lactic acid) transported from muscle cells through the Cori cycle or converts  
      it into pyruvate and glucose.
    ~Forms glucose from non-carbohydrate sources through gluconeogenesis.
-Regulates body and blood lipid level.
    ~Synthesis and breakdown of fat.
    ~Synthesis of cholesterol and phospholipids.
-Regulates blood and body proteins level.
    ~Deamination of excess amino acid into keto acid and ammonia.
    ~Ammonia produced is then converts into urea through ornithine cycle.
    ~Carries out transamination in which, the amino group from an amino acid is transferred to a
      keto acid.Transamination is used to synthesis non-essential amino acids.
-Stores vitamins and minerals such as ferum ions and vvitamin A,B12,D,and K.
-Produces plasma protein such as prothrombin and glubulins.
-Kupffer cell of the liver breaks down the old/worn-out erythrocytes.
-Produces bile,which is stored in the gall bladder.
-Performs detoxification of toxic substances such as ammonia and alcohol.
-In the foetal stage, liver produces erythrocytes.
-Stores blood.
-An active organ that produces a high amount of heat that can be used in the regulation of body temperature.