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Regulating Blood Sugar. SBI 4U January 11 th , 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 - PowerPoint PPT Presentation
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SBI 4UJANUARY 11 T H , 2013
Regulating Blood Sugar
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 problemsElectronic 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 LangerhansRegulate ability of tissues to metabolize fuel
substances
Insulin
Secreted by beta cells in isletsRise in blood glucose beta cells release insulinInsulin instructs target cells to uptake glucoseActs on skeletal muscles, liver cells and adipose
tissueIn liver, glucose inhibits breakdown of glycogenLowers fatty acid levels by promoting fatty acid
uptake in adipose tissueLowers amino acid level by promoting protein
synthesis
Insulin
Glucagon
Secreted by alpha cells in isletsOpposite to effects of insulinBreaks down glycogen in liverBreaks down fats into fatty acidsBreaks down proteins into amino acidsHelps 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 – glucocorticoidsKeeps brain well supplied in between mealsRaise blood glucose levels:1. Stimulate synthesis of glucose from non-carbs 2. Reduce glucose uptake by the body cells3. 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 insulinUsually diagnosed in childhoodTreated with daily administration of insulin
Type 2
Reduced insulin production or the inability of insulin to bind to its receptors properly
Usually diagnosed in adulthoodStrongly associated with obesityStrong genetic link more than 80% have a
family member with itTreatment involves diet and exercise
maintenance
Gestational Diabetes
Occurs in pregnant women due to high blood glucose level during pregnancy
Usually a temporary conditionCan increase the risk of mother and child
developing diabetes later on