Insulin is released when blood sugar is too high. It stimulates the removal of glucose in the blood. Glucagon is released when blood sugar is too low. It stimulates the release of glucose into the blood.
Insulin controls the conversion of glucose to glycogen; glucagon controls the conversion of glycogen to glucose. Glucose is a simple sugar which is soluble in blood plasma and the cells cytoplasm. Glycogen is a polysaccharide and is insoluble. Polysaccharides are formed from many of the simplest carbohydrates called monosaccharides, they are insoluble, so they are good stores of energy and can form independent structures such as cellulose cell walls. Glucose is therefore the usable form of carbohydrate and glycogen is the storage form of carbohydrate. The way in which the blood glucose level is kept within safe limits is shown on the sheet ‘Controlling Blood Sugar’.
As one of the cells main sources of energy glucose must always be available to the cells for respiration, to make sure there is always enough glucose the body keeps a constant amount of glucose on the blood. This blood glucose level is usually maintained at about 1 mg of glucose per cm3 of blood.
Diabetes is a condition in which the blood glucose concentration is higher than normal. Diabetes is usually the result of the pancreas failing to secrete enough insulin.
The symptoms of diabetes include excessive thirst, hunger and urine production, sweet smelling breath and a high ‘overflow’ of glucose into urine.
The long term affects of diabetes include premature ageing, cataract formation, the hardening of arteries and heart disease. Diabetes can be treated by a regular injection or pure insulin. Diabetes can also be caused by your diet, eating too much fat and sugar can cause diabetes. This type of diabetes can be treated by adjusting your diet and doesn’t need the injection of pure insulin.
A test for diabetes is clinistix which are thin strips of plastic with a small pad at the bottom. The pad contains an enzyme and a dye. If glucose is present the enzymes uses it to change the colour of the dye. A Clinistix dipped into a urine sample from a diabetic person will give a positive result within seconds. Clinistix are an excellent example of medical uses of enzymes.
