Metabolism of Carbohydrates


Metabolism of Carbohydrates


          The saliva, pancreas juice and enzymes present in the intestinal juice reaction on the carbohydrates taken as starch or sugar in meal in the digestive tract and transform them into monosacerides especially in the glucose. Glucose is absorbed by the villi of small intestine and reaches into the blood cells present inside them. From here, it goes into liver by the portal vein where it is used in the reactions of metabolism and the rest of glucose changes into glycogen by the hormone named insulin which is excreted by the pancreas and it remains present there. Some glucose reaches into skeletal muscles from the liver by the blood circulation and gathers there in the form of glycogen. Excessive quantity of glucose which does not gather in the liver and muscles gets changed into saturated fat and adipose tissues

          When the cells of the body need extra glucose for energy, the glycogen gathered in the liver is changed into glucose again because of the influence of epinephrine and glucagon and reaches all the body cells by mixing in the blood. 

          After the oxidation of glucose present in the body cells, required energy originates for all the bodily activities and heat for keeping the body heat and carbon dioxide and water originate as waste products that are excreted by the body. Carbon dioxide is expelled out from the body with breathing by the lungs. The water is expelled out from the body in form of urine by the kidneys and sweat by the skin. Supply of sufficient oxygen is essential for the complete oxidation of glucose. The oxidation of glucose remains incomplete in the deficiency of oxygen and because of this reason sufficient energy and heat is not available for the physical activities and glucose gets changed into lactic acid and due to this reason acute crap starts. This acute cramp can take muscles and heart walls in its grip because of too much labor or excessive running. In the case when oxygen is in sufficient quantity viz after anaerobic respiration, about 1/5 portion of lactic acid gets oxidized into carbon dioxide in the cells and in the water and the rest 4/5 portion gets changed into glycogen which is used by the muscles in need.