3. Physiological Roles of Calcium
Ca salt in bone provide structural integrity of the skeleton.
Absorption through small intestine, exit through kidney
Parathyroid and calciferol
2% of body weight where 99% in bones rest in blood and tissues.
8.6-10.3 mg/dl in blood
It acts as intra cellular messengers
4. It controls excitability of nerve cells and muscles.
Calcium signaling pathway
Regulation of cell membrane permeability and integrity.
Regulate muscular contraction and release of hormones
Essential for blood clotting
Play important role in SA node automaticity and AV Conduction
It helps in maintaining the structural function of Bones and teeth
5. Intake of Calcium
About 1000 mg of Ca Is ingested per day.
About 200 mg of this is absorbed into the body.
Absorption occurs in the small intestine, and requires vitamin D.
Dietary sources- Milk and dairy products, Egg yolk, Fish, beans.
Cow milk contains – 100 mg/ 100 ml
Human Milk – 30 mg/ 100 ml
6. Calcium Requirement
Recommended daily allowance
Adult – 500 mg / day
Children – 1200 mg/ day
Pregnancy & - 1500 mg / day
Lactation.
SITE : First part and second part of duodenum calcium absorbed
against concentration gradient and requires energy and a carrier
protein.
30 – 80 % of ingested calcium is absorbed.
Actively transported out of the intestinal cells with the help of calcium dependent
ATP.
8. Vitamin D
It may improve intestinal calcium absorption, suppress bone
remodelling and improve Bone mineral density in individuals
with marginal or deficient vit D status.
Calcitriol – suppresses the Parathyroid hormone function and
reduce bone turnover.
Dosage: 400-800 IU/ day.
It binds to a cytoplasmic Vitamin D receptor translocate to the
nucleus to increase synthesis of specific mRNA then it
regulate protein synthesis.
9. Thiazide diuretics
Reduce urinary calcium excretion and constrain bone loss in
patients with hypercalciuria.
Dosage –
Hydrochlorothiazide – 25 mg once or twice daily
10. Antacids
Taking too much calcium carbonate in the form of antiacids is
actually one of the more common cause of hypercalcemia
Lung cancer, breast cancer, and certain cancers of the blood
can cause hypercalcemia, that can become severe.
12. Loop diuretic (Furosemide)
They act on ascending limb of loop of Henle in the Kidney, act
by increasing the flow of urine by approximately 25% which also
cause loss of calcium.
Corticosteroids
It lead to rapid impairment of calcium transport in the intestine,
lead to decrease in the availability of calcium.
13. Tetracyclines
It binds with the calcium ions which cause decrease In the free
calcium in Blood
Laxative Abuse
Person attempt to eliminate unwanted calories, loose weight. It lead
to disturbance in electrolyte and mineral as well as decrease in
calcium level.
14. Other’s
Teriparatide
Recombinant preparation of 1-34 residues of amino acids
terminal of human Para thyroid hormone is used for the
treatment of severe osteoporosis
Cinacalcet
It activates the calcium sensing receptor in the parathyroids
and blocks Parathyroid hormone secretion.
It is indicated in secondary hyperparathyroidism due to renal
disease and in parathyroid tumor.
