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Essential Ion and Compound Balance and Homeostasis - Anatomy & Physiology (view source)
Revision as of 15:11, 4 September 2008
, 15:11, 4 September 2008→Acid Base
==Acid Base==
==Acid Base==
It is essential that 50-100meq of acid is excreted by the kidneys every day. This is achieved by secretion of H<sup>+</sup> in two regions of the nephron, the proximal tubule and the collecting ducts, and is essential for maintaining the acid base ratio, within the body, at the correct levels. If there is a net gain or loss of H<sup>+</sup> within the body then the kidneys will compensate for it. The H<sup>+</sup> ions cannot be secreted as free ions, however virtually all filtered HCO<sub>3</sub><sup>-</sup> must be reabsorbed. The result is that the H<sup>+</sup> ions bind to other filtered buffers which are not fully reabsorbed such as ammonia or phosphate. Extracellular pH is th main physiological regulator affecting how much acid is secreted. In pathological states circulating volume, aldosterone and plasma potassium affect it.
===The Role of the Kidney's in Acid Base===
The kidneys work with the respiratory system to regulate H<sup>+</sup>. Where as the respiratory systems quickly compensates for a problem its is left to the kidneys to actually remove the problem and restore a proper balance. They do this by altering the plasma concentration of HCO<sub>3</sub><sup>-</sup>.
=====Alkalosis=====
In a situation of alkalosis the kidneys allow more HCO<sub>3</sub><sup>-</sup> to be excreted. This results in an increase in an increase of un-buffered H<sup>+</sup> and thus returns the pH towards normal.
=====Acidosis=====
In a situation of increased H<sup>+</sup> levels the body is said to be in a state of acidosis and the kidneys stop excreting HCO<sub>3</sub><sup>-</sup> and the tubular cells produce more bicarbonate. This results in more H<sup>+</sup> being buffered and the pH increases back to normal
==Calcium==
==Calcium==