The liver: excretory role of the liver and homeostatic role of liver

The liver: excretory role of the liver and homeostatic role of liver

The liver 


Liver 

The liver is a central station of metabolism & consequently the body's central metabolic clearinghouse.
Homeostasis ( the protection of the internal environment of an organism from the harms of fluctuations i.e. alternations in temperature, pressure, etc.  in the external environment) and involved interactions with most organs system of the body.

Excretory role of liver

The liver supports the excretory role of the kidney by detoxifying many chemical poisons & produce ammonia NH3, urea CH4N2O & uric acid C5H4N4Ofrom the nitrogen of amino acid. Urea CH4N2O is the principal excretory product & liver produce it from the waste nitrogen through a metabolic pathway known as the urea cycle. Two ammonia NH3 & one carbon dioxide CO2 are shunted into the cycle to generate one molecule of urea CH4N2O. One ammonia  NHmolecule combines with carbon dioxide CO2 and ornithine C5H12N2O2 to form citrulline C6H13N3O3. Subsequently, another ammonia NH3combines to form arginine C6H14N4O2. The arginine C6H14N4O2 is split by arginase to form urea CH4N2O & the precursor ornithine C5H12N2O2 for next cycle.
The following diagram explains it well:



Homeostatic role of liver

The liver also has numerous crucial of homeostatic importance. These functions belong to synthesis, storage, conversion, recycling & detoxification categories.

Major homeostatic functions of the liver

  • Synthesis: Liver synthesizes nitrogenous substances like ammonia NH3, urea CH4N2O, uric acid C5H4N4O3. These nitrogenous substances support kidney in waste disposal.
  • Plasma proteins: Plasma proteins are synthesized by the liver. Plasma proteins like Prothrombin, fibrinogen plays a vital role in blood clotting and albumin helps to maintain the osmotic balance of the blood.
  • Bile: Lipids, cholesterol, lipoproteins regulate blood chemistry, store energy and help to maintain cell membranes.
  • Storage: Iron: oxygenation of tissues as a constituent of hemoglobin. Glycogen: Energy reserves energy storage and use. Oxygenation of tissues.
  •  Conversion: 1: Converts excess glucose in the blood into glycogen. 2: Converts lactic acid to glycogen. 3: Converts stored glycogen to glucose.
  • Recycling: Contents of old red blood cells e.g. iron & other constituents of hemoglobin ( a protein present in the blood): That play an important role in the oxygenation of tissue.
  • Detoxification: Many harmful chemicals e.g. food additives, pesticides, drugs, etc. assist kidneys in toxin disposal.


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