1. Regulating Blood Sugar
SBI 4U
January 11th, 2013

2. Regulating Blood Sugar
Regulation of blood  usually automatic (no thinking! Except when we are hungry)
Glucose used by all cells

3. Problems With Blood Sugar
Diabetes mellitus – blood glucose fluctuates abnormally
Serious health risks and long-term problems
Electronic monitors, modern syringes, pens and pumps

4. Hormones That Control Blood Sugar
Pancreas: long gland, located between S.I. and spleen. Most is an exocrine gland, 2% specialized endocrine cells – islets of Langerhans
Islets of Langerhans produce insulin and glucagon

5. Insulin & Glucagon Secreted by islets of Langerhans
Regulate ability of tissues to metabolize fuel substances

6. Insulin Secreted by beta cells in islets
Rise in blood glucose  beta cells release insulin
Insulin  instructs target cells to uptake glucose
Acts on skeletal muscles, liver cells and adipose tissue
In liver, glucose inhibits breakdown of glycogen
Lowers fatty acid levels by promoting fatty acid uptake in adipose tissue
Lowers amino acid level by promoting protein synthesis

7. Insulin

8. Glucagon Secreted by alpha cells in islets
Opposite to effects of insulin
Breaks down glycogen in liver
Breaks down fats into fatty acids
Breaks down proteins into amino acids
Helps maintain blood glucose level during fasting!

9. Alpha & Beta Cells Respond directly to glucose levels in their cytosol
Glucose level high  beta produces insulin, alpha decreases production of glucagon
Glucose level low  beta decreases production of insulin, alpha produces glucagon

10. Glucocorticoids
Adrenal cortex: release of steroid hormones – glucocorticoids
Keeps brain well supplied in between meals
Raise blood glucose levels:
Stimulate synthesis of glucose from non-carbs
Reduce glucose uptake by the body cells
Release fatty acids and amino acids into the blood as alternate fuels

11. Glucose Levels Varies throughout the day Due to meals and sleep
Decrease during night, level of glucose up after each meal

12. Glucose Levels
Hyperglycemia: glucose levels too high!

13. Glucose Levels
Hypoglycemia: glucose levels too low! Cold sweats, hunger, headaches, nervousness

14. Diabetes
High blood glucose level caused by problems with insulin production or action
3 classic symptoms: frequent urination, frequent thirst and increased appetite
Frequent urination: ability to take up glucose is impaired, high glucose in blood  more glucose in kidneys, more water pulled from blood by osmosis. Excessive amounts of urine
Need to replace excreted water causes thirst

15. Diabetes
Increased appetite because, cells cannot get enough energy from glucose – proteins and fats broken down instead
3 types of diabetes: Type 1, Type 2 and gestational diabetes

16. Type 1 Diabetes – Juvenile Diabetes
Beta cells in islets do not produce any insulin
Usually diagnosed in childhood
Treated with daily administration of insulin

17. Type 2
Reduced insulin production or the inability of insulin to bind to its receptors properly
Usually diagnosed in adulthood
Strongly associated with obesity
Strong genetic link  more than 80% have a family member with it
Treatment involves diet and exercise maintenance

18. Gestational Diabetes
Occurs in pregnant women due to high blood glucose level during pregnancy
Usually a temporary condition
Can increase the risk of mother and child developing diabetes later on