Bodyfluid and electrolit Physiology Department Medical Faculty, Hasanuddin University
Bodyfluid and electrolit
Physiology DepartmentMedical Faculty, Hasanuddin
University
KOMPOSISI Plasma Interstitiel intrasel (meq/l) ( meq/l) ( meq/l)
KATION Na 143,0 140,0 14,0K 4,2 4,0 140,0Ca 1,8 1,2 <1Mg 0,8 0,7 20,0 ANIONCl 108,0 108,0 4,0 HCO3 24,0 28,3 10,0HPO4 2,0 2,0 11,0Protein 1,2 0,2 4,0
Acid base balance
Physiology DepartmentMedical Faculty, Hasanuddin
University
Acid-Base Balance Precise H+ regulation is essential because the
activities of almost all enzyme, cell and body functions in the body are influenced by H+ concentration
Molecules containing hydrogen atoms that can release hydrogen ions in solutions are referred to as acids
A base is an ion or a molecule that can accept an H+, alkali is a molecule formed by the combination of one or more of the alkaline metals—sodium, potassium, lithium, and so forth—with a highly basic ion such as a hydroxyl ion (OH–).
Alkalosis refers to excess removal of H+ from the body fluids, in contrast to the excess addition of H+, which is referred to as acidosis.
Defenses Against Changes inHydrogen Ion Concentration Buffer system
Lung
Kidney
Buffering of Hydrogen Ionsin the Body Fluids
Bicarbonate Buffer System Phosphate Buffer System Proteins: Important Intracellular
Buffers
Bicarbonate Buffer System Consists of a water solution that
contains two ingredients: (1) a weak acid, H2CO3, and (2) a bicarbonate salt, such as NaHCO3
Extracellular fluid
Phosphate Buffer System The main elements of the
phosphate buffer system are H2PO4– and HPO4 =.
plays a major role in buffering renal tubular fluid and intracellular fluids.
Proteins: ImportantIntracellular Buffers Proteins are among the most plentiful
buffers in the body because of their high concentrations, especially within the cells
In the red blood cell, hemoglobin (Hb) is an important buffer, as follows:
60 to 70 per cent of the total chemical buffering of the body fluids is inside the cells, and most of this results from the intracellular proteins
Respiratory Regulationof Acid-Base Balance The second line of defense against
acid-base disturbances is control of extracellular fluid CO2 concentration by the lungs.
An increase in ventilation eliminates CO2 from extracellular fluid, which, by mass action, reduces the H+ concentration
Renal Control ofAcid-Base Balance The kidneys control acid-base balance
by excreting either an acidic or a basic urine
Thus, the kidneys regulate extracellular fluid H+ concentration through three fundamental mechanisms: (1) secretion of H+, (2) reabsorption of filtered HCO3- and (3) production of new HCO3-.