Mineral Metabolism

Question 1

General information about Calcium

Answer 1

Total 1 to 1.5 kg. Present in bones and teeth and ECF.
RDA - 800 to 1500mg/day
Functions - BCCI MENS Have Heart
Serum calcium - 9 to 11mg/dl
Absorption against concentration gradient from 1st and 2nd part of duodenum.

Question 2

Calcium homeostasis and regulation of calcium level in blood.

Answer 2

50 ionised 40 protein bound 10 bicarbonate and phosphorus

Vit D increase blood calcium by increasing absorption from intestine, increasing bone mineralisation and reabsorption of calcium from renal tubules.

PTH causes demineralisation of bones, absorption of calcium through Vit D and increase reabsorption from renal tubules.

Calcitonin causes mineralisation of bones, Decreased reabsorption from intestine and decreased reabsorption from renal tubules.

Question 3

Clinical significance of Calcium

Answer 3

Decrease in calcium level below 9mg/dl causes hypocalcemia and increase above 11mg/dl causes hypercalcaemia.

Hypocalcemia
Symptoms - convulsions , arrhythmias, tetany and spasm
Causes - rickets, osteomalacia, osteoporosis, decreased PTH and medullary carcinoma of thyroid.

Hypercalcaemia
Symptoms - pain in abdomen and bones, nausea , weakness , confusion and fatigue
Causes - PTH tumor, bone tumor or metastasis, multiple myeloma, pagets disease of bone.

Tetany
Serum calcium decreases below 7mg/dl
Signs
Carpopedal spasm, chvosteks sign, trousseau sign

Question 4

General information about Phosphorus.

Answer 4

Total body weight is 1kg .
80 in bones and teeth, 10 in muscles and RBCs and 10 in other compounds.
RDA - 800mg/dl
Function-
Bone and teeth formation
Synthesis of DNA, RNA and nucleoproteins
Formation of 3 ‘5’ phosphodiester
Component of nucleotide
Formation of phospholipids and phosphoproteins.
Enzyme regulation by phosphorylation
Synthesis of high energy compounds like ATP and creatine.
Major Intracellular Buffer in acid base balance
Synthesis of coenzymes like PLP, TPP, NADP, CoA .
Serum - 3 to 4 mg/dl
Blood - 30 to 40 mg/dl

Question 5

Deficiency manifestation of Phosphorus.

Answer 5

Normal serum - 3 to 4 mg/dl

Hypophosphatemia- due to
Malasorption, Malnutrition, Vit D deficiency and hyperparathyroidism.

Hyperphosphatemia - hypoparathyroidism, Vit D toxicity , cancer chemotherapy & secondaries in bone.

Question 6

Magnesium in short

Answer 6

Function -
Bone and teeth formation
Activation of enzymes like glucokinase, hexokinase, phosphofructokinase and adenylate cyclase.
Neuromuscular function

Deficiency-
Neuromuscular irritability
Convulsions
Spasm

Question 7

Sulphur in Short

Answer 7

Functions -
Important constituent in cysteine, cystine and methionine
Important in protein synthesis and disulphide bond formation
Constituent of thiamine, biotin, lipoic acid and CoA.
Glutathione, heparin, PAPS synthesis
Important for detoxification
Important for transmethylation