Dr.Thameem Latest Endocrinology notes Ebook PDF

Dr.Thameem Latest Endocrinology notes Ebook PDF The homeostatic control of hydrogen ion concentration in body uids is an essential requirement for life – to defend the relatively alkaline environment required for the most ef cient maintenance of body processes and organ function (Ayers & Dixon 2012). The degree of acidity or alkalinity of a solution is dictated by the pH (potential of hydrogen ion concentration). Large quantities of volatile acids are produced from cellular metabolism (mainly carbon dioxide – CO2), and non-volatile acids from the metabolism of fats and certain proteins.

Dr.Thameem Latest Endocrinology notes Ebook PDF A robust system for the maintenance of plasma pH is therefore required to defend the alkaline environment in the face of this massive, daily acid load.
An acid, by de nition, is a substance that can donate (give up) hydrogen (H+) ions. A strong acid donates a lot of hydrogen ions, while a weak acid will donate only a few. An alkaline (or base) is a substance that can accept (take up) H+ ions. Like an acid, a strong alkali can accept a lot of H+ ions, while a weak one can only accept a few. The pH is related to the actual H+ concentration. A low pH corresponds to a high H+ concentration and is evidence of an acidosis. Conversely, a high pH corresponds to a low H+ concentration, known as an alkalosis (Edwards 2008).

The interrelationship between oxygen (O2), H+, CO2 and bicarbonate (HCO3–) is central to the understanding of acid- base balance. It also re ects the physiological importance of the CO2/HCO3– buffer system, as illustrated in Figure 1.1 (below).