The HICS Physiology blog

Dr Ch V Jyotsna Assistant Professor, Critical Care NRI Medical College Guntur CALCIUM AND PHOSPHATE HOMEOSTASIS     Calcium is a divalent cation and an essential element required for bone mineralization, muscle contraction, neuronal transmission, blood clotting and also functions as second messenger for hormone secretion and regulation. 99% of calcium is found within the bones and less than 1% is found intracellular with 0.1% of calcium in the extracellular fluid. Out of the calcium found in ECF, 50% is in ionized form which is the biologically active form and around 45% of calcium is protein bound and remaining is bound to anions like citrate, phosphate, sulphate and bicarbonate. Normal serum calcium levels are 8.5 – 10 mg/dl. Ionized calcium levels are 1.15-1.25 mmol/L. (Figure 1)                 In case of hypoalbuminemia, there is decrease in total body calcium where as ionized calcium remains unaffected...

  Contributed by Srikant Behera, AIIMS    Bhubaneswar Water and Sodium Homeostasis Introduction: Disorders of serum sodium and water balance are the commonest electrolyte disorders encountered in intensive care unit (ICU) setting. It is associated with higher morbidity and mortality among ICU patient. So, a detail understanding of water and sodium homeostasis are paramount importance for critical care physicians. Water and sodium homeostasis refers to the complex physiological mechanisms that regulate the balance between the total body water and the concentration of sodium in the extracellular fluid. Maintaining this balance is essential because even small deviations can impair cellular function, and overall cardiovascular and neurological health. Body Water Distribution: Water is an important biological solvent and it provides an ideal environment for biochemical reactions. Total body water (TBW) accounts for about 50–60% of body weight (less in elderly and obese i...

  Dr. Prithwiraj Saha; MBBS, MD, DrNB ;  Associate Consultant, Fortis Escorts Heart Institute Delhi  Email-pitusri@gmail.com   Phone-983050964 8   Magnesium Hemostasis- Inside story of a neglected gem   Introduction:  Magnesium is the fourth most cation and the second most intracellular in the body. It has significant  function in excitable tissues and also acts as cofactor in hundreds of enzymatic reaction. It  plays an  important role in  DNA and protein synthesis, oxidative phosphorylation, neuromuscular excitability  and regulation of parathyroid hormone (PTH) secretion.    Distribution of Magnesium  Total magnesium content of body is around 25-30 grams(1000 mmol).This is much less than  contribution of other ions such as Calcium and phosphorus. About 99 percent of total magnesium is  present intracellularly and only 1 % is in the extracellular space. Intracelullar magnesium is stored...