Chronic elevated blood glucose levels lead to atherosclerosis and blood vessel damage

• Chronic elevation of blood glucose levels leads to the endothelium cells taking in more glucose than normal damaging the blood vessels.
• Atherosclerosis may develop leading to cardio vascular disease, stroke or peripheral vascular disease.
• Small blood vessels damaged by elevated glucose levels may result in haemorrhage of blood vessels in the retina, renal failure or peripheral nerve dysfunction.

Pancreatic receptors and the role of hormones

• Pancreatic receptors respond to raised blood glucose levels by increasing secretion of insulin from the pancreas.
• Insulin activates the conversion of glucose to glycogen in the liver decreasing blood glucose concentration.
• Pancreatic receptors respond to lowered blood glucose levels by increasing secretion of glucagon from the pancreas.
• Glucagon activates the conversion of glycogen to glucose in the liver increasing blood glucose concentration.
• During exercise and fight or flight responses, glucose concentrations in the blood are raised by adrenaline, released from the adrenal glands, stimulating glucagon secretion and inhibiting insulin secretion.

Diagnosis, treatments and role of insulin in type 1 and type 2 diabetes

• Type 1 diabetes usually occurs in childhood.
• A person with type 1 diabetes is unable to produce insulin and can be treated with regular doses of insulin.
• Type 2 diabetes typically develops later in life.
• The likelihood of developing type 2 diabetes is increased by being overweight.
• 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 to glycogen.
• In both types of diabetes individual blood glucose concentrations will rise rapidly after a meal
• The kidneys will remove some of this glucose, resulting in glucose appearing in urine.
• Testing urine for glucose is often used as an indicator of diabetes.
• The glucose tolerance test is used to diagnose diabetes.
• 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.

Obesity linked to cardiovascular disease and diabetes

• Obesity is a major risk factor for cardiovascular disease and type 2 diabetes.
• Obesity is characterised by excess body fat in relation to lean body tissue such as muscle.
• Obesity may impair health.
• Body mass index (BMI) is commonly used to measure obesity but can wrongly classify muscular individuals as obese.
• A body mass index (body mass divided by height squared) greater than 30 is used to indicate obesity.
• Obesity is linked to high fat diets and a decrease in physical activity.
• The energy intake in the diet should limit fats and free sugars as fats have a high calorific value per gram and free sugars require no metabolic energy to be expended in their digestion.
• Exercise increases energy expenditure and preserves lean tissue.
• Exercise can help to reduce risk factors for CVD by keeping weight under control, minimising stress, reducing hypertension and improving HDL blood lipid profiles.