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The Endocrine System

The Endocrine System. Endocrine System. Endocrine vs. Exocrine Organs are not physically connected Alters activities of target organs/cells Purpose: Growth/Development Reproduction Regulation Stress Reactions. Hormones are Activated By. Hormonal Humoral Neural.

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The Endocrine System

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  1. The Endocrine System

  2. Endocrine System • Endocrine vs. Exocrine • Organs are not physically connected • Alters activities of target organs/cells • Purpose: Growth/Development Reproduction Regulation Stress Reactions

  3. Hormones are Activated By • Hormonal • Humoral • Neural

  4. Gland/Hormone Functions • Some glands produce >1 hormone • Some hormones produced by >1 gland • Some organs have >1 function • Some hormones have >1 function

  5. Functions of Endocrine Glands • Endocrine Functions only Production Secretion • Contained within other organs which have other functions

  6. Categories of Glands • Central: Pituitary Hypothalamus • Peripheral: Thyroid Pineal Adrenals Gonads Parathyroids Pancreas Thymus Others

  7. Hypothalamus • Found on floor of diencephalon • Neural and endocrine functions • Biofeedback mechanism for: Osmotic pressures Temperature regulations Metabolic functions

  8. Pituitary • Extends from Hypothalamus-behind sphenoid bone • “Master Gland” of body • Anterior- Portal network • Posterior- Neural-contains axons of Hypothalamus neurons

  9. Anterior Pituitary • GH- Growth Hormone • Prolactin • TSH- Thyroid Stimulating Hormone • ACTH- Adrenocorticotropic • FSH- Follicle Stimulating Hormone • LH- Luteinizing Hormone

  10. Posterior Pituitary • ADH- Anti-Diuretic Hormone • Oxytocin

  11. Pituitary Disorders • Acromegaly- Hypersecretion of GH • Dwarfism- Hyposecretion of GH

  12. Thyroid • Inferior to larynx • 2 Lobes • T3- Triiodothyronine • T4- Thyroxine • Calcitonin

  13. Thyroid Disorders • Hypothyroidism- Hyposecretion • Hyperthyroidism- Hypersecretion • Graves Disease • Goiters- iron deficiencies

  14. Parathyroids • 4 small glands posterior surface of thyroid • Parathyroid hormone • Responsible for osteoclast of bone • Decreases blood phosphate levels (By way of kidneys) • Enhances activation of Vitamin D

  15. Parathyroid Disorders • Hyperparathyroidism “Moan and groan, stones and bones”

  16. Pineal Gland • Forms part of diencephalon • Melatonin • Inhibits hypothalamus release of gonadotropins • Melatonin-decreases in light/increase in dark (circadian rhythm)

  17. Thymus Gland • Posterior to sternum, around great vessels • Thymosin • Both lymphatic and endocrine • Lymphatic- produces T-lymphocytes • Endocrine- ‘programs’ T-cells

  18. The Adrenals • Located on superior end of each kidney • Medulla- inner gland • Cortex- outer gland

  19. Adrenal Medulla • Sympathetic preganglionic fibers synapse on cells in medulla • Release of epinephrine/norepinephrine into general circulation

  20. Adrenal Cortex • Produce over 30 steroid hormones • Three main cortical hormones Mineralocorticoids Glucocorticoids Sex hormones

  21. Mineralocorticoids • Regulate levels of electrolytes and water in extracellular fluid • 95% are aldosterone • Sodium reabsorption • Potassium excretion

  22. Glucocorticoids • Influence carbohydrate metabolism • Important in body’s response to stress • 95% cortisol (hydrocortisone) stimulates gluconeogenesis secretion is regulated by ACTH

  23. Sex Hormones • Androgens (testosterone) • Estrogens • Both are secreted in greater numbers by gonads

  24. Adrenal Disorders • Cushing’s disease- cortisol over-production secondary to increased ACTH • Addison’s Disease- cortisol/aldosterone deficiencies

  25. Gonads • Testes- males Testosterone • Ovaries- females Estrogens Progesterone • Both produce hormones/gametes

  26. Pancreas • Retroperitoneal-posterior to stomach • Exocrine & Endocrine • Endocrine- islets of Langerhans Alpha Beta Delta

  27. Alpha cells • 20% of islets • Hormone glucagon • Stimulates breakdown of glycogen in liver- raises glucose levels in blood (glycogenolysis & glyconeogenesis)

  28. Beta Cells • 75% of islets • Hormone- insulin • Decreases glucose levels

  29. Glucose Metabolism • Organic components of food: Carbohydrates (instant-energy) Glucose Fats Fatty acids/glycerols Proteins Amino acids

  30. Carbohydrate Metabolism • Insulin is released by humoral, hormonal, neural means Increased glucose Parasympathetic stimulation Gastrointestinal hormones

  31. Carbohydrate Metabolism • 60% of carbohydrates are stored as glycogen in liver • If muscles are not exercised after eating-stored as muscle glycogen

  32. Glycolysis • Glucose is broken down into pyruvate and lactate- releasing 2ATPs (Anaerobic metabolism) Krebs Cycle

  33. Fat Metabolism • A third of any glucose passing through liver is converted to fatty acids • Fatty acids are converted to triglycerides and stored in adipose tissue

  34. Fat Metabolism • Without insulin, fat is broken back down into triglycerides/cholesterol  CAD • Fatty acids are also broken down into ketone bodies

  35. Protein Metabolism • In absence of insulin- protein storage stops and breakdown begins (muscle) • Amino acid breakdown for energy leads to increased urea in urine organ dysfunction

  36. Pancreas Disorders • Diabetes- • Type 1- Juvenile onset • Type 2- Mature onset • Gestational diabetes

  37. Type 1 Diabetes • Insulin dependant • S/S: polyuria polydipsia polyphagia blurred vision weight loss

  38. Type 2 Diabetes • Generally non-insulin dependant • Has ability to make small amounts of insulin • Can develop into insulin dependant

  39. Gestational Diabetes • Develops during pregnancy • Deficiencies in insulin leads to inability to metabolize carbohydrates • Generally disappears after delivery

  40. Insulin Agents • Early- porcine, bovine • Recent- genetic engineered human insulin • Protein • Rapid, intermediate and long-term • Combination of long-term, rapid each day

  41. Insulin Types • Regular- Fast acting 0.5-1 hour onset 6-8 hour duration • NPH- Intermediate 1-1.5 hour onset 24 hour duration

  42. Insulin Types • Ultralente- Long acting 4-6 hour onset 36 hour duration • Oral agents: • Diabinese (chlorpropamide) • Orinase (tolbutamide) • Micronase (glyburide) • Glucotrol

  43. Diabetic Emergencies • Hypoglycemia • Hyperglycemia • Diabetic Ketoacidosis (DKA) • Hyperosmolar Hyperglycemic Nonketotic Coma (HHNK)

  44. Hypoglycemia • Rapid on-set • < 60 mg/dl • Causes: too much insulin decreased intake salicylates excessive activity beta blockers emotional stress hypothermia chronic alcoholism sepsis

  45. S/S of Hypoglycemia • Altered LOCs- irritability, nervousness, confusion, combative • Cool, clammy • Weak, rapid pulse • Snoring,  salivation • Normal BP

  46. Diabetic Ketoacidosis • Fat metabolism leads to ketoacids • Acidosis leads to  K+ in circulation & hyperkaluria  K+ deficiency • Osmotic diuresis  dehydration, electrolyte imbalances

  47. S/S of DKA • Warm, dry skin • Dry mucous membranes • Tachycardia, thready pulse • Postural hypotension • Weight loss • ‘Polys’

  48. S/S of DKA • Abdominal pain • Anorexia, nausea/vomiting • Acetone breath • Kussmauls • Decreased LOC

  49. Hyperosmolar Hyperglycemic Nonketotic Coma • Generally Type II diabetic • Osmotic diuresis secondary to  sugars • Not acidotic as in DKA • Factors: Geriatric Preexisting diseases Increased insulin requirements Medication use- thiazide, diuretics Parenteral/enteral feedings

  50. S/S of HHNK • Weakness • Thirst • Polyuria • Weight Loss • Extreme dehydration

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