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Importance of calcium: Ca ++ regulates: Neural function Muscle contraction

Importance of calcium: Ca ++ regulates: Neural function Muscle contraction Secretion of some hormones Blood clotting. The four parathyroid glands are located adjacent to the much larger thyroid gland. Secretion of p ara th ormone (PTH) is a direct response to an abnormal

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Importance of calcium: Ca ++ regulates: Neural function Muscle contraction

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  1. Importance of calcium: • Ca++ regulates: • Neural function • Muscle contraction • Secretion of some hormones • Blood clotting

  2. The four parathyroid glands are located adjacent to the much larger thyroid gland. Secretion of parathormone (PTH) is a direct response to an abnormal decrease in the concentration of calcium ions.

  3. RICKETS • Insufficient Vitamin D3 • Bones fail to mineralize due to lack of calcium • Bones are soft and easily fractured • Bones become distorted due to weight bearing • A major health problem in the US in the 1930’s • Vit D fortification of milk was introduced and largely • eliminated the problem • Still a major health problem in many developing nations • Has recently re-emerged in the US particularly among • African American infants and children

  4. Vitamin D • Ca++ and PO4-- regulation • Blood pressure regulation • Immunomodulatory effects • Anti-cancer effects • Anti-thrombotic effects Most cells and tissues of the body have Vitamin D receptors

  5. Vitamin D deficiency • Definition: serum 25-hydroxyvitamin D < 30 ng/ml • Epidemiology: 1 billion people worldwide have vitamin D • deficiency or insufficiency • Risk factor for: • osteopenia • muscle weakness • increased risk of some cancers • autoimmune disease • hypertension • cardiovascular disease • asthma Source: Vitamin D deficiency, Holick, MF, New Engl. J. Med. 357:266-280, 2007

  6. Vitamin D deficiency Risk factors: Reduced skin synthesis: sunscreen, skin pigment, aging, season, latitude Decreased bioavailability: malabsorption (GI problems), obesity (sequestration in fat) Drugs that increase catabolism Breastfeeding Decreased synthesis: (liver or kidney failure) Heritable Disorders

  7. Source: Vitamin D deficiency, Holick, MF, New Engl. J. Med. 357:266-280, 2007 * * 5 to 10 minutes of exposure (depending on the time of day, season, latitude, and skin sensitivity) of the arms and legs to direct sunlight.

  8. Hypercalcemia • Serum calcium > 10.5 mg/100ml • High serum calcium makes nerves and muscle hypoexcitable • Signs and symptoms • Kidney stones • Bone pain and fractures • Anorexia • Constipation • Fatigue, weakness, and joint pain • Depression, memory loss, confusion, lethargy • Primary cause: • Hyperparathyroidism,excess PTH release usually from • a parathyroid adenoma

  9. Hypocalcemia • Serum calcium > 9 mg/100ml • low serum calcium makes nerves and muscle hyperexcitable • Signs and symptoms • Numbness and tingling • Muscle cramps and pain • Irritability • Impaired mutation • Seizures • Cardiac problems • Laryngospasm • Bronchospasm • Tetany • Primary cause: • PTH or Vitamin D deficiency

  10. OSTEOPOROSIS

  11. OSTEOPOROSIS • Loss of bone matrix and mineralization

  12. SYMPTOMS OF OSTEOPOROSIS • Often asymptomatic • Bone fractures (vertebrae, hip, wrists) • Bone pain • Back pain, neck pain • Loss of height • Stooped posture

  13. From: Kettyle and Arky, Endocrine Pathophysiology, Lippincott -Raven

  14. From: Kettyle and Arky, Endocrine Pathophysiology, Lippincott -Raven

  15. From: Kettyle and Arky, Endocrine Pathophysiology, Lippincott -Raven

  16. RISK FACTORS FOR OSTEOPOROSIS • Age (affects ¼ of women over 50) • Race (highest in Caucasians) • Gender (more common in females) • Loss of growth promoting hormones (menopause) • Immobilization/lack of exercise • Genetics • Diet (calcium and vitamin D3) • Smoking and alcohol • Excess of hormones that cause bone resorption • Thyroid hormone • Corticosteroids

  17. From: Kettyle and Arky, Endocrine Pathophysiology, Lippincott -Raven

  18. RISK FACTORS FOR OSTEOPOROSIS • Age (affects ¼ of women over 50) • Race (highest in Caucasians) • Gender (more common in females) • Loss of growth promoting hormones (menopause) • Immobilization/lack of exercise • Genetics • Diet (calcium and vitamin D3) • Smoking and alcohol • Excess of hormones that cause bone resorption • Thyroid hormone • Corticosteroids

  19. RISK FACTORS FOR OSTEOPOROSIS • Age (affects ¼ of women over 50) • Race (highest in Caucasians) • Gender (more common in females) • Loss of growth promoting hormones (menopause) • Immobilization/lack of exercise • Genetics • Diet (calcium and vitamin D3) • Smoking and alcohol • Excess of hormones that cause bone resorption • Thyroid hormone • Corticosteroids

  20. PREVENTION • Dietary supplementation • -calcium • - vitamin D • Exercise • Reduce factors leading to falls

  21. TREATMENT • Hormone replacement therapy • -(side effects) • Calcitonin • Alendronates (Fosamax)

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