Regulation Of Calcium And Vitamin D Flashcards
What is vitamin d
A hormone
What are the hormones involved in the control of blood calcium
Vitamin D
PTH
Calcitriol
What is the anatomy of the parathyroid glands
Would be 4 Lental size nodes on the thyroid gland
Some people can have up to 6
What is the main function of the PTH
Controls the uptake of calcium
What is the role of the kidney in calcium regulation
Reabsorption of the calcium
PTH can also act and on kidney and decreased urine loss
What is the role of the gut in the calcium regulation
PTH would stimulate the vitamin D
form the D3 (which would be the active form)
Allows the transcellular uptake from the GI tract
What is the role of the bone in the calcium regulation
Increased resorption (when would have the low levels of calcium)
What would happen in the hypercalcemia
Stones (in the kidney)
Moans (depression and psychiatric issues)
Groans (abdominal issues)
What happens in hypocalcemia
Pins and needles
Muscle spasms
Paralysis
Convulsions (that would happen during a seizure)
What is another name for calcitriol
1,25-dihydroxycholecalciferol
What is calcium normal bound to
Albumin
What would happen to the levels of albumin during acute illness
Albumin would decrease
What are the chef cells
Cells within the parathyroid gland that would produce the hormones
What is the function of calcitonin
Weak effect
Deposition of the calcium in the bone
What happens to PTH when there would be a low calcium level
Increase transcription and gene expression
Increased calcitriol
More ca2+ reabsorption
Increased bone break down
Less bone building,
So would allow the amount of calcium in the body to increase
What happens to the PTH when the levels of calcium would increase
Decreased PTH
Decreased calcitriol (less calcium from the gut)
Less reabsorption
Low plasma calcium
Less bone break down
More bone building
Why do you need to be careful when taking a calcium sample
Would start a clotting cascade
Could then lead to the damage of the blood cells
What do you need to take a sample of blood calcium in
A plain tube
Not a sodium citrate or an EDTA as this would cause the calcium to chelate
What can malignancies do to calcium
Can alter the calcium homeostasis
B - BREAST
L - LUNG
T - THYROID
-
K - KIDNEY
P - PROSTATE
What is parathyroid hormone - related peptide
Hormone that would be secreted by the tumour cells
squamous tumours of the lung Or Head and neck of pancreas
Bind to PTH receptors and mimics PTH
No release of C-1 hyrdroxylase enzyme would normally increase the calcitriol
(1,25-dihydroxycholecalciferol)
What are the sources of vitamin D
Sun light (direct)
Oily fish (mackerel)
Fortified Cereals
Fortified mild
Butter and margarine
What happens in a mild vitamin D deficiency
25-50 nmol/L
Increased PTH (as low vitamin D would have the decrease uptake of the calcium)
High bone Breakdown
What would happen in a moderate vitamin D deficiency
12.5 - 25 nmol/L
Reduced Bone density
High bine breakdown
Increased risk of hip fracture
What would happen in the severe vitamin D deficiency
<12.5 nmol/L
Rickets in children
Osteomalacia (rickets in adults)
