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The Endocrine System

The Endocrine System. Hormones. Chemical substances secreted by endocrine (ductless) glands. These chemicals are carried by blood to their respective target cells. Tend to control slow long-term activities in the body. What would be a slow long-term process?. Primary Functions of Hormones.

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The Endocrine System

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  1. The Endocrine System

  2. Hormones Chemical substances secreted by endocrine (ductless) glands. These chemicals are carried by blood to their respective target cells. Tend to control slow long-term activities in the body. What would be a slow long-term process?

  3. Primary Functions of Hormones • Homeostasis • Growth and Development • Reproduction • Energy Metabolism • Behavior

  4. Chemical Composition of Hormones Steroids Proteins/Polypeptides Amines

  5. Steroids

  6. Some Protein/Polypeptide Hormones Glucagon Insulin Oxytocin ADH Calcitonin

  7. Amines tyrosine thyroxine epinephrine

  8. stimulates glucose release from liver glucagon from pancreas stimulates inhibits blood glucose high Negative Feedback Loop blood glucose low

  9. Biological Cycles

  10. hormones endocrine cell receptor protein target cell Mechanism of Action on Target Cells Water soluble hormone response

  11. hormones endocrine cell intracellular receptor target cell Mechanism of Action on Target Cells lipid soluble hormone response

  12. Tropic Versus Nontropic Hormones Tropic hormones- stimulate the production and secretion of hormones by other endocrine glands; ex. TSH Nontropic hormones- stimulates cellular growth, metabolism, or other functions; ex. thyroxine

  13. hypothalamus pineal gland pituitary gland thyroid gland thymus gland parathyroid glands adrenal glands pancreas ovaries testes Major Endocrine Organs

  14. pineal gland hypothalamus pituitary gland Endocrine Organs of the Brain

  15. Pineal Gland Produces melatonin (synthesized from seratonin, a derivative of tryptophan) • Secreted directly in CSF to blood • High levels at night make us sleepy; low level during day • Pineal gland is stimulated by darkness and inhibited by light • Function in regulating circadian rhythms (sleep, body temp, appetite)  biological clock

  16. The Pituitary Gland

  17. Posterior Pituitary

  18. Hormones of the Posterior Pituitary Antidiuretic Hormone (ADH) Oxytocin

  19. Oxytocin (+ feedback) loop oxytocin

  20. Anterior Pituitary

  21. Hormones of the Anterior Pituitary • Growth Hormone (GH) • Thyroid Stimulating Hormone (TSH) • Adrenocorticotropic Hormone (ACTH) • Gonadotropins (FSH, LH) • Prolactin (PRL) • Melanocyte-stimulating Hormone (MSH)

  22. Growth Hormone (GH) • Stimulates protein building • Stimulates cell growth (cell size and number), especially in muscle and bone. • Also stimulates fat breakdown.

  23. strenuous exercise GH Levels sleep awake

  24. Dwarfism hyposecretion of GH Little People Big World Kenadie - worlds smallest girl due to primordial dwarfism

  25. Gigantism hypersecretion of GH Bao Xishun, a 7ft 8.95in herdsman from Inner Mongolia

  26. Acromegaly hypersecretion of GH 7 ft 1 ¼ inches

  27. Thyroid-Stimulating Hormone (TSH) • Acts on the thyroid gland, stimulating it to release T3 & T4 • These thyroid hormones increase glucose catabolism and body heat production. • Regulated via negative feedback

  28. Adrenocorticotropic Hormone (ACTH) • Acts on the adrenal cortex, stimulating it to secrete glucocorticoids (e.g., cortisol). • Helps make glucose from amino acids and fatty acids • Regulated via negative feedback

  29. The Thyroid Gland larynx thyroid trachea

  30. Thyroid Hormones Thyroid gland selectively uptakes iodine to produce T3 & T4 • Thyroxine (T4) • Triiodothyronine (T3) • Both control metabolic rate and cellular oxidation • Calcitonin - lowers blood Ca++ levels and causes Ca++ reabsorption in bone

  31. Goiter Lack of iodine in diet hyposecretion of T3 & T4

  32. hyposecretion of T3 & T4 Cretinism

  33. Myxedemahyposecretion of T3 & T4 After thyroid treatment myxedema

  34. Exophthalmos-hyperthyroidism

  35. Parathyroid Glands

  36. Parathyroid Hormone (PTH) • PTH release: • stimulates osteoclasts to reabsorb bone Hyperparathyroidism- too much Ca++ drawn out of bone; could be due to tumor Hypoparathyroidism- most often follow parathyroid gland trauma or after removal of thyroid--- tetany, muscle twitches, convulsions; if untreatedrespiratory paralysis and death

  37. The Pancreas

  38. Pancreas: • Regulates glucose uptake by cells • Controlled via negative feedback: insulin & glucagon • Blood sugar level: 90 mg/mL

  39. capillaries alpha cells beta cells Islets of Langerhans

  40. Insulin • Produced by the  cells of the Islets of Langerhan • Catalyze oxidation of glucose for ATP production • Lowers blood glucose levels by promoting transport of glucose into cells. • Stimulates glucose uptake by the liver and muscle cells. • Stimulates glycogen synthesis in the liver and muscle cells. • Also stimulates amino acid uptake and protein synthesis of muscle tissue

  41. Glucagon • Produced by the  cells of the Islets of Langerhans • Stimulates change of glycogen to glucose in the liver. • Synthesis of glucose from lactic acid and non carbohydrate molecules such as fatty acids and amino acids • Causes  in blood glucose concentration hypoglycemic- low blood sugar; deficient in glucagon

  42. Diabetes Mellitus

  43. Type I Diabeteshyposecretion of insulin insulin dependant juvenile onsetType II Diabeteslate onset (adult) insensitivity of cells to insulin manage by exercise & diet

  44. Symptoms (Type I): • sugar in blood and urine • urinate too often and produce too much urine • Too thirsty • Too hungry

  45. Type I (IDDM): • Arteriosclerosis • Cardiovascular problems • Gangrene • Eye problems • Kidney damage

  46. Treatment: • Insulin replacement • Pancreas transplant • Pancreatic cell transplant • Fetal pancreatic islet cell transplant

  47. Adrenal Glands

  48. Hormones of the Adrenal Medulla • Adrenalin (epinephrine): converts glycogen to glucose in liver • Noradrenalin(norepinephrine): increases blood pressure • (sympathetic nervous system) • Corticosteroids: glucose levels)

  49. Hormones of the Adrenal Cortex • Glucocorticoids- cortisol • Decrease protein synthesis • Increase release and use of fatty acids • Stimulates the liver to produce glucose from non carb’s • Mineralcorticoids- aldosterone • Stimulates cells in kidney to reabsorb Na+ from filtrate • Increases water reabsorption in kidneys • Increases blood pressure • Sex Steroids- small amts (androgens) • Onset of puberty • Sex drive

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