Glucose is needed by cells for respiration. The concentration of glucose in the blood must be maintained at a constant level and controlled carefully.
Chronic elevated blood glucose levels can lead the epithelial cells lining blood vessels to absorb far more glucose than normal. This can cause atherosclerosis and blood vessel damage.
Insulin is a hormone produced by the pancreas. It regulates glucose concentrations in the blood.
Pancreatic receptors respond to raised blood glucose levels by increasing the secretion of insulin from the pancreas.
Insulin activates the conversion of glucose to glycogen in the liverdecreasing blood glucose concentration.
Glucagon:
Pancreatic receptors respond to lowered blood glucose levels by increasing the secretion of glucagon from the pancreas.
Glucagon activates the conversion of glycogen to glucose in the liverincreasing blood glucose concentration.
During exercise and the fight or flight response, glucose concentrations in the blood are raised by adrenaline released from the adrenal glands. This stimulates glucagon secretion and inhibitsinsulin secretion.
Type 1 Diabetes:
A person with type 1diabetes is unable to produce insulin and can be treated with regular doses of insulin.
The onset of Type 1 diabetes usually occurs in childhood.
Type 2 Diabetes:
In Type 2 diabetes, individuals produce insulin, but their cells are less sensitive to it. This insulin resistance is linked to a decrease in the number of insulin receptors in the liver, leading to a failure to convert glucose into glycogen.
Type 2 diabetes typically develops later in life. The likelihood of developing type 2 diabetes is increased by being overweight.
Urine Test:
In both types of diabetes, individual blood glucose levels rise rapidly after a meal. The kidneys remove some of this glucose, resulting in glucose appearing in urine.
Testing urine is often used as an indicator of diabetes.
Glucose Tolerance Test
The blood glucose concentrations of the individual are initially measured after fasting. The individual then drinks a glucose solution and changes in their blood glucose concentration are measured for at least the next two hours.
The blood glucose concentration of a diabetic usually starts at a higher level than that of a non-diabetic.
During the test, a diabetic’s blood glucose concentration increases to a much higher level than that of a non-diabetic and takes longer to return to its starting concentration.
Small blood vessels damaged by elevated glucose levels may result in haemorrhage of blood vessels in the retina, renal failure or peripheral nerve dysfunction.