Lecture27: Parathyroid, Calcitonin Flashcards
What are the hormones involved in calcium level regulation?
PTH, Calcitonin, and Calcitriol
What does PTH do to calcium levels?
Increases it
What does PTH act on, target organs?
Bone, kidneys and intestines
How does PTH increase bone resporption and calcium mobilization?
It increases osteoclastic activity and proliferation
Which vitamin increases calcium absorption from intestine?
Vitamin D3
How is PTH secretion regulated?
Via calcium levels, low calcium means high PTH secretion
Do high phosphate concentrations stimulate PTH secretion?
Yes
does Calcitriol inhibit PTH secretion?
Yes
Hypoparathyroidism leads to?
Tetany, hypocalcemia
What is Tetany?
Muscle spacticity caused by decreased calcium levels
Causes of Tetany?
Hypocalcemia, hypoparathyroidism, vit D deficiency
What’s a carpopedal spasm?
Spontaneous contraction in the muscles of the extremities
What is Latent Tetany?
It needs test to provoke the spasms, like Chovostek’s sign
Carpopedal spams occur also in which muscles?
Respiratory muscles
How to Test for Latent Tetany?
Chovostek’s sign and Trousseau’s sign
Hyperparathyroidism leads to bone fractures and cysts how?
The increased bone resorption makes it de-calcified
Most common complication of increased bone resorption is?
Ostitis Fibrosa Cystica
What are the effects of hypercalcemia?
Muscular weakness, pain, constipation, RENAL STONES
What are the effects of Calcitriol on the intestine?
Increases both calcium facilitated diffusion and active transport
How is Calcitriol synthesis regulated?
Negative feedback, low calcium increases Calcitriol synthesis
Name 2 functions of Calcitonin?
Reduces bone resporption and increases calcium secretion
How is Calcitonin regulated?
When calcium increases, calcitonin increases. Positive feedback
