Calcium/Phosphate Flashcards
(30 cards)
List some signs/symptoms of hypercalcaemia
Stones, moans + groans
- kidney calculus (kidney stones)
- lethargy
- depression
- constipation
- kidney damage
Where is the biggest store of Ca/Pi in the body?
Skeleton/teeth in the form of hydroxyapatite crystals
Where are other bodily stores of calcium/phosphate?
Soft tissues
Extra cellular fluid
Causes of hypocalcaemia?
Insufficient dietary intake
PTH deficiency- rare + deadly
What can cause an endogenous PTH deficiency? Why is it so dangerous?
Accidental removal of PT glands
Hyperexcitability of NMJ- tetany and eventual paralysis
Causes of hypercalcaemia
- Primary hyperparathyroidism
- Hyperthyroidism- TF increased bone turnover
- malignancy- some secrete PTHrp, some secrete factors that act locally to activate osteoclasts
Which are the most common causes of hypercalcaemia?
Primary hyperparathyroidism- parathyroid adenoma OR parathyroid hyperplasia
List some symptoms/signs of hypocalcaemia.
Pins + needles Tetany Paralysis Convulsions (Due to hyperexcitability of NMJ)
What is PTHrp and what does it do?
Parathyroid hormone related peptide
Mimics PTH
Binds to PTH receptors
Normal role- tooth eruption, mammary development, lactation, placental transfer of calcium
What are calcitriol and calcitonin?
Calcitriol is the activated form of vitamin D3- (1,25 OH vitamin D3)
Calcitonin is a hormone secreted from parafollicular cells of thyroid gland that decreases calcium conc
Where is PTH secreted from?
Chief cells of the parathyroid gland
Where is calcitonin secreted from? And where does it act upon?
Parafollicular thyroid gland cells
Acts upon bone and kidney
What effects does calcitonin have in the kidneys?
Decrease reabsorption of calcium and phosphate
What effect does calcitonin have on bone?
Decrease osteoclast activity
What does 1, 25 OH vitamin D3 do to calcium/Phosphate levels? How?
Increases their levels by ^reabsorption in kidneys, ^osteoclasts in bones, ^absorption in the small intestine
Names for vitamin D?
Calcitriol
1, 25 OH Vitamin D3
Which enzyme is involved in the activation of Vitamin D3?
1 α hydroxylase
What is 1-α hydroxylase activated by?
PTH
What does PTH do to kidneys?
Activates 1 α-hydroxylase
Increases absorption of Ca from distal convoluted tubule
Decreases reabsorption of Pi from proximal convoluted tubules
What does 1, 25 OH vitamin D3 do to calcium/Phosphate levels? How?
Increases their levels by ^reabsorption in kidneys, ^osteoclasts in bones, ^absorption in the small intestine
What molecule is 1-α hydroxylase activated by?
PTH
What does PTH do to kidneys?
Activates 1 α-hydroxylase
Increases absorption of Ca from distal convoluted tubule
Decreases reabsorption of Pi from proximal convoluted tubules
What do high levels of calcium trigger?
Down regulation of transcription of PTH
Up regulate production of Calcitonin
What do low levels of calcium trigger?
Up regulation of PTH production
Down regulate production of Calcitonin
