Control Of Calcium Flashcards
How is calcium found in the boood?
Fee ions in solution (45%), bound to negatively chardged serum proteins such as almbumin (45%) complexed with free ions (10%)
What are the three hormones involved in the regulation of calcium?
Parathyroid hormone, active vitamin D (calcitrol)
What happens in cases of hypercalcemia?
The formation of kidney stones, constipation, diarrhoea, dehydration, kidney damage, tiredness p, depression.
What happens in cases of hypercalcemia?
Hyperexcitability in the nervous system, including neruomuscular junctions, which can lead to parasthenia, tetany, paralysis and even convulsions.
What is the role of parathyroid hormone?
It is used for short term control and raises serum calcium, can be used to active calictrol for longer term activation.
What is the role of calcitrol?
Longer term raising of calcium levels.
How is vitamin D activated?
Two hydroxylation reactions.
What is the role of parathryoid hormone related peptide?
It is produced by a tumour and can lead to hypercalcemia, and is excreted by some cancer cells, leading to humoural hypercalcemia malignancy, can increase calcium release from bone and does not increase calcitrol concentration.
What are the potential roles of calcitonin?
This lowers serum calcium levels in animals, however in humans they lack pathology associated with hyper and hypo secretion, and if the thyroid gland is removed the lack of calcitonin is not seen to have a negative affect.
Waht cellular processes is calcium involved in?
Hormone secretion, muscle contraction, exocytosis, activation and inactivation, intracellular second messenger.
