Regulating Blood Sugar SBI 4U January 11th, 2013

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

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

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

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

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

Insulin

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!

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

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

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

Glucose Levels Hyperglycemia: glucose levels too high!

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

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

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

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

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

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