2.8

• Aerobic respiration

  Process where glucose and oxygen are broken down to release energy (ATP), carbon dioxide and water
• Aerobic respiration

  Glucose + Oxygen → Energy + Carbon dioxide + Water
• Chronic elevation of blood glucose

  Leads to atherosclerosis and blood vessel damage
• Chronic elevation of blood glucose

  • Due to untreated diabetes
  • Causes endothelium cells lining blood vessels to absorb more glucose than normal, damaging the blood vessels
• Damage to small blood vessels by elevated glucose levels

  May result in haemorrhage of blood vessels in the retina, renal failure or peripheral nerve dysfunction
• Chronic elevation of blood glucose

  May also lead to atherosclerosis, resulting in cardiovascular disease, stroke or peripheral vascular disease
• Negative feedback

  A mechanism where a change is detected and hormones are released to bring the change back to normal
• Pancreatic receptors

  • Detect changes in blood glucose concentration
  • Respond by releasing hormones to bring blood glucose back to normal
• Hormones involved in blood glucose regulation

  • Insulin
  • Glucagon
  • Adrenaline
• Blood glucose regulation

  1. Receptors in pancreas detect increase in blood glucose

  2. Pancreas secretes insulin

  3. Insulin activates conversion of glucose to glycogen in liver, decreasing blood glucose

  4. Receptors in pancreas detect decrease in blood glucose

  5. Pancreas secretes glucagon

  6. Glucagon activates conversion of glycogen to glucose in liver, increasing blood glucose
• Adrenaline

  • Hormone released from adrenal glands
  • Stimulates glucagon secretion and inhibits insulin secretion to raise blood glucose during exercise and fight-or-flight responses
• Comparisons between type 1 and type 2 diabetes

  • Type 1 usually occurs in childhood, person unable to produce insulin, treated with insulin doses
  • Type 2 develops later in life, more likely if overweight, person produces insulin but cells are less sensitive to it (insulin resistance)
• Both type 1 and type 2 diabetes

  Blood glucose levels rise rapidly after a meal, kidneys unable to reabsorb all the glucose, resulting in glucose appearing in urine
• Glucose tolerance test

  • Used to diagnose diabetes
  • Measures blood glucose changes after drinking glucose solution
  • Diabetic's blood glucose increases to much higher level and takes longer to return to normal
• Obesity is a major risk factor for cardiovascular disease and type 2 diabetes
• Body Mass Index (BMI)


  • Body mass divided by height squared
  • Used to measure obesity, but can wrongly classify muscular individuals as obese
• BMI greater than 30 is used to indicate obesity
• Role of diet and exercise in reducing obesity and cardiovascular disease

  • Obesity linked to high fat diets and decreased physical activity
  • Exercise can help reduce risk factors for cardiovascular disease by controlling weight, minimising stress, reducing hypertension and improving HDL blood lipid profiles