Biochemistry · MU Sofia

70-Metabolism of Calcium And Phosphorus

Covers how calcium and phosphorus are obtained, absorbed, stored and kept in balance, set out separately for each mineral with their functions and sources. It then explains hormonal control by parathyroid hormone, calcitriol and calcitonin, the roles of osteoblasts, osteocytes and osteoclasts in bone formation and remodelling, and osteoporosis covering causes, diagnosis by DEXA scan, and hormone replacement therapy with its benefits and risks. It ends with four multiple-choice questions and their answers.

Inside: 11 sections · 8 labelled pictures · 10 flashcards · 4 min

Topic 70 of 70 in the MU Sofia syllabus for Biochemistry (Medicine, Year 2). The free AceMed note covers it in 8 sections, about 533 words (4 min of reading), with 10 flashcards.

In this note

  1. Introduction
  2. Metabolism of Calcium and Phosphorus
  3. Regulation
  4. Bone Formation
  5. Osteoporosis
  6. Hormone Replacement Therapy (HRT)
  7. MCQs
  8. Answers:

Metabolism of Calcium and Phosphorus

Calcium:

  • Functions: Vital for bone structure, muscle contraction, nerve transmission, blood clotting, and enzyme activity.
  • Sources: Dietary intake from dairy products, leafy greens. Absorbed in the small intestine, mainly in the duodenum and jejunum.
  • Storage: 99% stored in bones and teeth as hydroxyapatite. The remaining 1% is found in blood and extracellular fluids.
  • Homeostasis: Maintained by the balance between dietary intake, intestinal absorption, renal excretion, and bone resorption and formation.

Metabolism of Calcium and Phosphorus

  • Phosphorus:
  • Functions: Essential for bone structure, energy production (ATP), nucleic acids, and cell membranes (phospholipids).
  • Sources: Dietary intake from meat, dairy, nuts, and grains. Absorbed in the small intestine.
  • Storage: 85% stored in bones and teeth, the rest in cells and extracellular fluids.
  • Homeostasis: Regulated by dietary intake, renal excretion, and bone metabolism.

Regulation

Hormonal Regulation:

  • Parathyroid Hormone (PTH):
  • Source: Parathyroid glands.
  • Function: Increases blood calcium levels by stimulating bone resorption, increasing renal reabsorption of calcium, and promoting activation of vitamin D.

Continue reading free

The whole note, all 8 sections, is free with an AceMed account, with its 10 flashcards. Premium adds flashcard recall, highlights and Ask AI.

Start freeAlready a member? Open the note