Hormones affecting glucose


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  • Hormones affecting glucose

    1. 1. Endocrine SystemPart 2: Glucose Regulation
    2. 2. Glucose in Blood Glucose is an important fuel for cells Pancreas maintains blood glucose levels by secreting hormones
    3. 3. Pancreas Exocrine system: secretion of hormones through ducts Exocrine cells:  98%-99% of pancreas by mass  Produce digestive enzymes released into small intestine http://media-2.web.britannica.com/eb-media/17/74317-004-9B143D52.jpg
    4. 4. Pancreas Endocrine cells:  1%-2% of pancreas by mass  Scattered throughout the pancreas  Islets of Langerhans http://media-2.web.britannica.com/eb-media/17/74317-004-9B143D52.jpg
    5. 5. Islets of Langerhans Alpha cells: secrete glucagon Beta cells: secrete insulin Insulin and glucagon are antagonistic hormones http://www.rajeun.net/diabetes-pancreas.gif
    6. 6. Insulin Stimulant:  Blood glucose level rises above a set point  Observed naturally after eating a meal Effect:  Uptake of glucose by body cells through facilitated diffusion by activating glucose transporters  Inhibits the livers breakdown of glycogen  Inhibits liver’s conversion of amino acids and glycerol to glucose Result:  lowering blood glucose level  decrease stimulus for insulin release
    7. 7. Glucagon Stimulant:  Lowered blood glucose  Glucose cleared from the blood stream Effect:  Liver to increase breakdown of glycogen  Liver convert amino acids and glycerol to glucose Result:  Higher blood glucose level  Decrease stimulus for glucagon release
    8. 8. Insulin Function When is insulin released? after eating hyperglycemia decreased blood cellular signals for beta cells sugar insulin release increased glucose uptake glycogen production in liver
    9. 9. Glucagon Function What does glucagon do? breaks down glycogen hypoglycemia increased blood cellular signals for alpha cells sugar glucagon release glucose release from liver glucose production in liver
    10. 10. Comparing Insulin & GlucagonCharacteristics Insulin GlucagonSituationStimulant:Blood glucoselevelsEffect: GlucoseuptakeEffect: Glycogenbreakdown
    11. 11. Comparing Insulin & GlucagonCharacteristics Insulin GlucagonSituation After a meal Between mealsStimulant:Blood glucoselevelsEffect: GlucoseuptakeEffect: Glycogenbreakdown
    12. 12. Comparing Insulin & GlucagonCharacteristics Insulin GlucagonSituation After a meal Between mealsStimulant: IncreasedBlood glucoselevelsEffect: Glucose IncreaseuptakeEffect: Glycogen Decreasebreakdown
    13. 13. Comparing Insulin & GlucagonHormone Insulin GlucagonSituation After a meal Between mealsStimulant: Increased DecreasedBlood glucoselevelsEffect: Glucose Increase DecreaseuptakeEffect: Glycogen Decrease Increasebreakdown
    14. 14. Diabetes Mellitus Cause Decreased insulin levels  Type 1 diabetes: Immune system attacks insulin producing cells  Type 2 diabetes: reasons not related to autoimmunity Type 2: diabetes: Decreased responsiveness of cells to insulin  Inability of insulin to regulate blood glucose levels  Impairment of ability to remove glucose from the bloodstream
    15. 15. Diabetes Mellitus Types Type 1 Type 2 (Insulin dependent) (Non-insulin dependent)Onset Childhood Adult (past age 40) PregnancyMolecular Insulin deficiency Insulin resistanceCause (unresponsive receptors) and deficiencyCause Genetic Obesity Autoimmune disorderTreatment Daily insulin injections Exercise & dietary control drugs
    16. 16. Diabetes Mellitus Effect Glucose unavailable to body cells  Hyperglycemia: high glucose in blood  Excessive hunger  Fat used for cellular respiration  Increased blood viscosity and decreased blood flow ▪ leads to blurry vision (poor blood flow in capillaries of retina) ▪ foot infections (gravity cause blood to pool in feet) Kidneys start to excrete glucose  Glucosuria: glucose in urine, “sweet” urine  Frequent urination  Persistent thirst
    17. 17. Diabetes Insipidus Cause Inability of kidneys to conserve water Cause: deficiency in ADH  ADH controls excretion rate by reabsorbing water from urine into blood
    18. 18. Diabetes Insipidus Symptoms Excessive thirst Frequent urination Dilute urine Urine does not contain glucose and is not sweet
    19. 19. Diabetes Insipidus Treatment Drinking sufficient water Take ADH medication
    20. 20. Canadian Connection Frederick Banting & Charles Best Nobel Prize – 1923 insulin isolation  tied off ducts to digestive tract  cell producing digestive enzymes shrivelled  only islets of Langerhans remained
    21. 21. Banting and Best Banting and Best began their experiments by removing the pancreas from a dog. This resulted in the following:  Its blood sugar rose.  It became thirsty, drank lots of water, and urinated more often.  It became weaker and weaker.  The dog had developed diabetes. They then isolated “insulin” and injected it back into the dogs and they seemed to be cured.
    22. 22. Leonard Thompson January 1922 in Toronto, Canada 14-year-old boy was the first to be treated with insulin injections
    23. 23. Stress RegulationWhat is Stress? The feeling of alarm or distress when reacting to particular event Can be physical, emotional, cognitive or mental
    24. 24. Stress Response Natural response Prepares an individual to handle the stressor (an event that provokes stress) Types:  Short term: responses are immediate  Long term: responses are ongoing and can cause detrimental side effects on the individual
    25. 25. Adrenal Gland Secretes stress response hormones Location: adjacent to kidneys Structure:  Adrenal cortex : outer portion, involved with long- term stress response  Adrenal medulla : inner portion, involved with short-term stress response
    26. 26. Short Term Stress Response
    27. 27. Short-term Stress Response Stress excites nerve cells to release a neurotransmitter: acetylcholine (ACh) Stimulates adrenal medulla to release catecholamines: epinephrine and norepinephrine
    28. 28. Catecholamines Synthesized from tyrosine Secreted in response to positive or negative stress by the adrenal medulla Types:  Epinephrine (adrenaline)  Norepinephrine (noradrenaline)
    29. 29. Catecholamines Tyrosine
    30. 30. Effects Stimulates the “fight-or-flight” response Increase metabolism  Cellular respiration produces ATP  Need oxygen  Need energy source (glucose)
    31. 31. Effects: Energy Source Increased blood glucose levels  Glycogen  glucose  more ATP readily available Stimulates the release of fatty acids from fat cells to supply the body with more energy Decreased kidney and digestive activity
    32. 32. Effects: Oxygen Increased blood pressure and blood flow  oxygen is distributed to cells faster Increased breathing rate Relaxes/contracts certain blood vessels  overall effect of redirecting blood away from non- vital areas  increasing blood flow to the heart, brain, and skeletal muscles Increased alertness
    33. 33. Application Epinephrine is present in epinephrine autoinjectors (EpiPens)
    34. 34. Long Term Stress Response
    35. 35. Long-Term Stress Response:Neuroendocrine pathway  CRH  ACTH  Corticosteroid  Glucocorticoid  Mineralcorticoid
    36. 36. Long-Term Stress Response: Neuroendocrine pathwayLocation HormoneStimulus StressHypothalamus Corticotropin-releasing Hormone (CRH)Anterior Pituitary Adrenocorticotropic Hormone (ACTH)Adrenal Cortex Corticosteroids: Glucocorticoids (e.g. cortisol) Mineralocoritcoids (e.g. aldosterone)Effect Increase glucose production Increase oxygen delivery
    37. 37. Corticotropin-ReleasingHormone (CRH) Neuropeptide hormone Released from hypothalamus Cause: stressful stimuli Stimulates anterior pituitary to synthesize ACTH
    38. 38. Adrenocorticotropic Hormone(ACTH) Polypeptide hormone Tropic hormone Produced from anterior pituitary Stimulates adrenal cortex to synthesize corticosteroids
    39. 39. Corticosteroids steroids produced and released from the adrenal cortex Type Example Glucocorticoid Cortisol Mineralcorticoid Aldoesterone Sex hormones testosterone
    40. 40. GlucocorticoidsEffects: Energy source Affects glucose metabolism  Synthesize of glucose from non-carbohydrate sources  Liver breaks down muscle protein in skeletal muscles to glucose Occurs when body needs more glucose than what the liver can produce from its storage of glycogen
    41. 41. MineralocorticoidsEffects: Indirectly on oxygen Hormone that affects the body’s osmotic balance  Stimulates reabsorption of salt and water by kidneys Cause increase in blood volume and pressure Increase oxygen delivery
    42. 42. Compare Short & Long Term Stress ManagementStress Short term Long termHormones Epinephrine Glucocorticoid (cortisol) Norepinephrine Mineralcorticoid (aldoesterone)Energy Glucose from Glucose from non- glycogen stores carbohydrate sourceOxygen Increase heart Increase reabsorption rate, pressure, flow of salt and water, blood & resp rate, volume, pressure & regulate vessel size flow
    43. 43. Stress Associated Disorders
    44. 44. Hypersecretion: Cushing’s Disease Overproduction of corticosteroids (glucocorticoid) Cause: pituitary tumour (excess ACTH) Treatment: surgery, radiation
    45. 45. Cushing’s Disease Effects Mimic diabetes:  Hyperglycermia (high blood glucose)  Glucosuria (glucose in urine)  Protein shortage (protein converted to glucose) Physical effects:  Excess glucose deposited as body fat in abdomen, face, above shoulder blades ▪ Weight gain, “moon face” and “buffalo hump”  Appendages remain thin  Muscle weakness, prone to bruising  Weak skeleton, prone to fractures
    46. 46. Hyposecretion: Addison’s Disease Failure to produce adequate levels of glucocorticoid (cortisol) Cause: autoimmune / adrenal gland disorders  immune system gradually destroys the adrenal cortex Treated with gluco/mineralocorticoids
    47. 47. Addison’s Disease Symptoms major weight loss dizziness, vomiting and nausea extreme pain in stomach