Endocrinology 17 Flashcards
What kind of hormone is parathyroid hormone?
It is a peptide hormone
How does PTH affect blood calcium and phosphate?
- Increases blood calcium
* Decreases blood phosphate
What are the three targets of PTH?
- Bone
- Kidney
- GI tract
What does parathyroid hormone do to bone?
It increases the reabsorption of calcium from bone and moves it to the blood
How can PTH be used as a treatment for osteoporosis?
PTH can sometimes have an opposite effect
How does PTH affect the kidney?
It increases the reabsorption of calcium and increases the excretion of phosphate ions
How does PTH affect the gut?
It increases the absorption of calcium and phosphate from the gut
What kind of hormone is Active vitamin D3?
A steroid like molecule
Where is active vitamin D3 secreted from?
The kidneys
How does active vitamin D3 affect blood calcium and phosphate?
It increases the levels of blood calcium and phosphate by increasing their absorption in the GI tract
How do active vitamin D and PTH work together in the bone?
They increase the reabsorption of calcium and phosphate (increase breakdown)
What does a lack of calcitonin do?
It does not give rise to any obvious disorders within the body
What family of hormones is Calcitonin?
A peptide
Where does calcitonin come from?
C-cells/parafollicular cells in the thyroid gland
How does Calcitonin affect calcium and phosphate levels in the blood?
It decreases both calcium and phosphate levels in the blood
What is secretion of calcitonin increased by?
Increased blood calcium
What are the effects of too much PTH?
It eats away at the bones causing them to be more fragile. It can also cause the precipitation of calcium into kidney stones
What are the effects of too little PTH?
Tetany - Muscles go into spasms due to increased levels of blood calcium
What are the disease of too little Active vitamin D?
Rickets in kids and osteomalacia in adults where there is softening of the bones because no calcium and phosphate is absorbed from the gut
What does low extracellular calcium favor?
The opening of sodium channels
What does high extracellular calcium favor?
Inhibition of the opening of sodium channels and decreases excitability
