IHS: Exam 3: ABG 100% REVISION 2023//2024

IHS: Exam 3: ABG 100% REVISION 2023//2024 Acid • a molecule that can act as a proton (H+) donor. • Strong acid readily and irreversible gives up an H+, and a strong base avidly binds H+ Base • a molecule that can act as a proton acceptor. • A weak acid or base reversible donates H+ or reversible binds H+. Acidemia blood pH 7.35 Acidosis is the process that lowers pH - H+ concentration in blood is increased Alkalemia blood pH 7.45 Alkalosis is the process that raises pH - Decrease in H+ concentration Base Excess amount of strong acid or strong base required to return 1 L of whole blood exposed in vitro to a PaCO2 of 40 mmHg to a pH of 7.4 Normal base excess is ______. 0 Base deficit: 0 metabolic acidosis Base excess: 0 metabolic alkalosis Regulation of Hydrogen Ion Concentration Buffers Ventilation Renal responses Normal Hydrogen ion concentration in arterial blood is __________. 35 -45 mmol/L Normal pH of arterial blood is ____________. 7.35 - 7.45 Normal bicarbonate ion concentration is ____________. 24 mEq/L (+/- 2 mEq/L) Intracellular Hydrogen ion concentration is approx. ________ nmol/L or pH of __________. 160, 6.8 buffering system •A substance within a solution that can prevent extreme changes in pH •Composed of a base molecule and its weak conjugate acid How does the buffer system work? When needed: 1. Base binds to the excess H+ 2. Weak acid protonates excess base molecules Henderson-Hasselbalch equation (image) Dissociation ionization constant (pKa): the strength of an acid derived from the Henderson-Hasselbalch equation Three main points about the H-H equation: 1. The pH is positively related to HCO3- 2. The pH is inversely related to the PaCO2 3. The ratio of HCO3- to the PaCO2 defines what the pH will be. pKa -the pH at which an acid is 50% protonated and 50% deprotonated -Tells us the strength of an acid -Signifies the pH at which the acid is: • 50% protonated (have H+ attached) • 50% deprotonated (have lost H+ ions) protonation when acid donates H+ to the base Hydrochloric acid (strong acid) pKa is ____. -7 Carbonic acid (weak acid) pKa is ___. 6 4 most important bufferi