2.8 Blood Glucose Levels & Obesity Flashcards
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 cardiovascular disease, stroke or peripheral vascular disease.
Damage of small blood vessels
Small blood vessels damaged by elevated glucose levels may result in haemorrhage of blood vessels in the retina, renal failure or peripheral nerve dysfunction.
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 & 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.
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.
Glucose Tolerance Test
Used to diagnose diabetes and involves the following:
• 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
A major risk factor for cardiovascular disease and type 2 diabetes and
is characterised by excess body fat in relation to lean body tissue such as muscle.
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.
Body Mass Index (BMI)
Commonly used to measure obesity but can wrongly classify muscular individuals as obese.
BMI = body mass (kg) divided by height (m) squared. A BMI greater than 30 is used to indicate obesity.
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 blood lipid profiles.