kelenjar partiroid-endokrinologi


Published on

buat yang mau bikin tugas mata kuliah endokrinologi. semoga bermanfaat

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

kelenjar partiroid-endokrinologi

  2. 2. Parathyroid Gland <ul><li>4 small glands located on the dorsal side of the thyroid gland </li></ul><ul><li>essential for life </li></ul><ul><li>produces parathyroid hormone </li></ul><ul><li>responsible for monitoring plasma Ca 2+ </li></ul>
  3. 3. Anatomy & Location of Parathyroid Gland
  5. 5. Parathyroid Hormone (PTH) <ul><li>a peptide hormone that increases plasma Ca 2+ </li></ul><ul><li>causes increase in plasma Ca 2+ by: </li></ul><ul><li>Mobilization of Ca 2+ from bone </li></ul><ul><li>Enhancing renal reabsorption </li></ul><ul><li>Increasing intestinal absorption (indirect) </li></ul>
  6. 6. Regulation of PTH release by Plasma Ca 2+ Levels <ul><li>PTH is released by chief cells in the parathyroid gland. </li></ul><ul><li>Chief cells contain receptors for Ca 2+ </li></ul><ul><li>A decrease in plasma Ca 2+ levels mediates the release of PTH </li></ul><ul><li>Conversely, hypercalcemia inhibits PTH release </li></ul>
  7. 7. Physiologic Anatomy of the Parathyroid Gland
  8. 8. Effect of Parathyroid Hormone on Calcium and Phosphate Concentrations in the ECF
  9. 9. The rise in calcium concentration is caused by two Effects <ul><ul><ul><li>1. an effect of PTH to increase calcium and phosphate absorption from the bone </li></ul></ul></ul><ul><li>2. a rapid effect of PTH to decrease the excretion of calcium by the kidneys </li></ul><ul><ul><ul><li>- Parathyroid Hormone Increased Calcium and Phosphate Absorption from the Bone </li></ul></ul></ul><ul><li>- Rapid Phase of Calcium and Phosphate Absorption – Osteolysis </li></ul><ul><li>- Slow Phase of Bone Absorption and Calcium Phosphate Release – Activation of the Osteoclasts </li></ul><ul><li>- Parathyroid Hormone Decreases Calcium Excretion and Increase Phosphate Excretion in the Kidneys </li></ul><ul><li>- Parathyroid Hormone Increases Intestinal absorption of Calcium and Phosphate </li></ul><ul><li>- Cyclic Adenosine Monophosphate Mediates the Effects of Parathyroid Hormone </li></ul>
  10. 10. <ul><ul><ul><li>ACTIONS OF PTH ON TARGET ORGANS </li></ul></ul></ul><ul><li>1. BONES OR SKELETON </li></ul><ul><li>Calcium and Phosphate absorption from bones </li></ul><ul><li>a. Rapid Phase – osteolysis </li></ul><ul><li>b. Slow Phase – activation of osteoclasts </li></ul><ul><ul><ul><ul><ul><li>1. immediate activation of osteoclasts that are already formed </li></ul></ul></ul></ul></ul><ul><li>2. formation of new osteoclasts from osteoprogenator cells </li></ul><ul><li>2 . INTESTINES </li></ul><ul><ul><ul><li>Enhances both Ca and PO4 absorption from the intestines by increasing formation of 1, 25 dihydroxycholecalciferol from vitamin </li></ul></ul></ul><ul><li>3. KIDNEYS </li></ul><ul><li>a. Increased renal tubular reabsorption of calcium in the distal tubules and collecting ducts </li></ul><ul><li>b. diminished proximal tubular reabsorption of PO4 </li></ul>
  11. 11. EFFECTS OF PTH ON TARGET ORGANS <ul><li>1 . Blood Calcium and Phosphate </li></ul><ul><ul><ul><li>a. Hypercalcemia </li></ul></ul></ul><ul><li>b. Hypophosphatemia </li></ul><ul><li>2. Urine </li></ul><ul><li>a. Hypocalciuria </li></ul><ul><li>b. Hyperphosphatemia - phosphaturic </li></ul>
  12. 12. Control of Parathyroid Hormone Secretion
  13. 13. CALCITONIN <ul><ul><ul><li>Peptide hormone secreted by the thyroid gland that tends to decrease plasma calcium concentration. </li></ul></ul></ul><ul><ul><ul><li>Two ways: </li></ul></ul></ul><ul><li>1. decrease absorptive activities of the osteoclasts and the osteocytic effect of the osteocytic membrane – immediate effect </li></ul><ul><li>2. decrease formation of new osteoclasts – more prolonged effect </li></ul>Increased Plasma Calcium Concentration Stimulates Calcitonin Secretion Calcitonin Has a Weak Effect on Plasma Calcium Concentration in Adult Human
  14. 14. SUMMARY OF CONTROL OF CALCIUM ION CONCENTRATION <ul><li>1. Buffer Function of the Exchangeable Calcium in Bones - the First Line of Defense </li></ul><ul><li>2. Hormonal Control of Calcium ion concentration – the Second Line of Defense </li></ul><ul><li>a. PTH </li></ul><ul><li>b. Calcitonin </li></ul>
  15. 15. PARATHYROID HORMONE and BONE DISEASE <ul><li>1. Hypoparathryroidism </li></ul><ul><li>a. Tetany – Calcium concentration is 6-7 mg% - Larygospasm </li></ul><ul><li>Signs of Latent Tetany </li></ul><ul><ul><ul><ul><ul><li>1. Chvostek’s sign </li></ul></ul></ul></ul></ul><ul><li>2. Trousseau’s sign </li></ul><ul><li>b. Impairment of blood clotting </li></ul>
  16. 17. <ul><ul><ul><li>2. Hyperparathyroidism </li></ul></ul></ul><ul><ul><ul><ul><li>a. Bone Disease </li></ul></ul></ul></ul><ul><ul><ul><ul><li>- broken bones </li></ul></ul></ul></ul><ul><ul><ul><ul><li>- Cystic bone disease – Osteitis Fibrosa Cystica or Von Recklinghausen’s Disease </li></ul></ul></ul></ul><ul><ul><ul><li>b. Effects of Hypercalcemia </li></ul></ul></ul><ul><ul><ul><li>1. Rise of calcium to 12-15 mg% </li></ul></ul></ul><ul><ul><ul><li>- depression of central and peripheral nervous system </li></ul></ul></ul><ul><ul><ul><li>- muscular weakness, constipation, abdominal pain, peptic ulcer, lack of appetite, depressed relaxation of the heart during diastole </li></ul></ul></ul>
  17. 18. <ul><ul><ul><li>2. Formation of kidney stones </li></ul></ul></ul><ul><ul><ul><li>3. Parathyroid hormone poisoning and metastatic calcification- 17 mg% Calcium </li></ul></ul></ul><ul><ul><ul><ul><li>alveoli of the lungs – tubules of kidneys </li></ul></ul></ul></ul><ul><ul><ul><ul><li>thyroid gland – walls of the arteries </li></ul></ul></ul></ul><ul><ul><ul><ul><li>stomach mucosa </li></ul></ul></ul></ul>
  18. 19. BONE DISEASES <ul><li>Rickets – Vitamin D Deficiency </li></ul><ul><ul><ul><li>- occurs mainly in children </li></ul></ul></ul><ul><li>- results from calcium or phosphate deficiency in the ECF caused by lack of VitaminD </li></ul><ul><li>- develops tetany </li></ul>
  19. 20. <ul><li>Osteomalacia – “Adult Rickets” </li></ul><ul><ul><ul><li>- deficiency of both vitamin D and calcium occurs as aresult of steatorrhea (failure to absorb fat) because vitamin D is fat soluble </li></ul></ul></ul><ul><li>- “Renal rickets” is a type of osteomalacia that results from kidney damage </li></ul><ul><ul><ul><li>Osteoporosis – Decreased Bone Matrix </li></ul></ul></ul><ul><ul><ul><li>- the most common of all bone disease in adults especially in old age </li></ul></ul></ul><ul><li>- results from diminished bone matrix rather than poor bone calcification </li></ul>
  20. 21. <ul><ul><ul><li>Causes: </li></ul></ul></ul><ul><ul><ul><li>a. lack of physical stress on the bones due to inactivity </li></ul></ul></ul><ul><ul><ul><li>b. malnutrition – sufficient protein matrix cannot be formed </li></ul></ul></ul><ul><ul><ul><li>c. lack of vitamin C – necessary for secretion of intercellular substances </li></ul></ul></ul><ul><ul><ul><li>d. postmenopausal lack of estrogen secretion – estrogen have osteoblast-stimulating activity </li></ul></ul></ul><ul><ul><ul><li>e. old age – diminished growth hormone </li></ul></ul></ul><ul><ul><ul><li>f. Cushing’s syndrome – massive glucocorticoids cause decreased deposition of protein thus depressing osteoblastic activity </li></ul></ul></ul>