Endocrine Part 4 Calcium- Miliotis Flashcards
Why is calcium critical for normal physiology? (6) IHBNMB
Calcium is essential for intracellular signalling, hormone secretion, blood clotting, neural excitability, muscle contraction, and building/maintaining bones.
Where is calcium located in the body and give their presence in percentage?
Most calcium (99%) is in bones, with smaller amounts in extracellular fluid (0.1%) and inside cells (0.9%).
What are the three hormones that control plasma calcium levels?
Parathyroid hormone (PTH), calcitriol, and calcitonin.
What are osteoblasts and what do they promote the formation of?
Osteoblasts are bone-forming cells that promote the formation of calcium phosphate complexes in bones.
What is the function of osteoclasts and what is the significance of this function?
Osteoclasts break down bone (bone resorption) to release calcium into the bloodstream.
What are osteocytes and what is their job?
Osteocytes are mature bone cells (previously osteoblasts) that maintain the bone matrix.
How does the PTH increase plasma calcium levels? (3) (BKC)
PTH increases calcium resorption from bone, enhances kidney calcium reabsorption, and stimulates calcitriol production.
What is the role of calcitriol (Vitamin D3)? (small intestine, renal, bone)
Calcitriol increases calcium absorption from the small intestine, enhances renal calcium reabsorption, and moves calcium from bone.
How does calcitonin regulate calcium levels? (reduces what, how, promote what)
Calcitonin reduces plasma calcium by inhibiting osteoclast activity and promoting bone formation by osteoblasts.
What are the symptoms of hypercalcemia? CFBKC (5)
Symptoms include constipation, fatigue, bone pain, kidney stones, and confusion.
what internal parts of the body does PTH use to increase and decrease phosphate in the bloodstream?
PTH increases phosphate release from bone and decreases phosphate reabsorption in the kidney
What are the symptoms of hypocalcemia? CATS
Symptoms include convulsions, arrhythmias, tetany (muscle spasms), and seizures.
How is blood phosphate controlled by calcitriol?
calcitriol increases phosphate absorption by the intestine.
How do osteoblasts promote osteoclast formation?
through the RANKL/RANK interaction.
What is the role of osteoprotegerin (OPG) and what does it prevent?
OPG blocks the RANKL/RANK interaction, preventing excessive osteoclast formation and bone resorption.
