Physiological Effects of Alkalosis

Alkalosis

PHYSIOLOGICAL EFFECTS OF ALKALOSIS

Alkalosis increases the affinity of hemoglobin for oxygen and shifts the oxygen dissociation curve to the left, making it more difficult for hemoglobin to give up oxygen to tissues. Movement of H⁺ out of cells in exchange for the movement of extracellular K⁺ into cells can produce hypokalemia. Alkalosis increases the number of anionic binding sites for Ca²⁺ on plasma proteins and can therefore decrease ionized plasma [Ca²⁺], leading to circulatory depres-sion and neuromuscular irritability. Respiratory alkalosis reduces cerebral blood flow, increases sys-temic vascular resistance, and may precipitate coro-nary vasospasm. In the lungs, respiratory alkalosis increases bronchial smooth muscle tone (broncho-constriction), but decreases pulmonary vascular resistance.