1 PowerPoint Lecture Outlines to accompany Hole’s Human Anatomy and Physiology Eleventh Edition Shier  Butler  Lewis Chapter 21 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2 Chapter 21 Water, Electrolyte, and Acid-Base Balance Of the 40 liters of water in the body of an average adult male, about two-thirds is intracellular, and one-third is extracellular

3 Fluid Compartments

4 Body Fluid Composition EC fluids high concentrations of sodium, calcium, chloride & bicarbonate ions IC fluids high concentrations of potassium, magnesium, phosphate, & sulfate ions

5 Movement of Fluids Between Compartments Net movements of fluids between compartments result from differences in hydrostatic and osmotic pressures

6 Water Balance urine production is most important in the regulation of water balance

7 Regulation of Water Intake

8 Regulation of Water Output

9 Electrolyte Balance

10 Regulation of Electrolyte Output: Potassium and Sodium Balance

11 Calcium Balance

12 Sources of Hydrogen Ions

13 Strengths of Acids and Bases Weak bases ionize less completely and release fewer OH - Strong bases ionize more completely and release more OH - Weak acids ionize less completely and release fewer H + Strong acids ionize more completely and release more H +

14 Regulation of Hydrogen Ion Concentration acid-base buffer systems respiratory excretion of carbon dioxide renal excretion of hydrogen ions

15 Acid-Base Buffer Systems Bicarbonate System the bicarbonate ion converts a strong acid to a weak acid carbonic acid converts a strong base to a weak base H + + HCO 3 -  H 2 CO 3  H + + HCO 3 - Phosphate System the monohydrogen phosphate ion converts a strong acid to a weak acid the dihydrogen phosphate ion converts a strong base to a weak base H + + HPO 4 -2  H 2 PO 4 -  H + + HPO 4 -2

16 Acid-Base Buffer Systems Protein Buffer System NH3 + group releases a hydrogen ion in the presence of excess base COO - group accepts a hydrogen ion in the presence of excess acid

17 Respiratory Excretion of Carbon Dioxide

18 Renal Excretion of Hydrogen Ions

19 Summary of Acid-Base Balance

20 Clinical Application Acid-Base Imbalances If the pH of arterial blood drops to 6.8 or rises to 8.0 for more than a few hours, the person usually cannot survive factors that lead to respiratory acidosis acidosis versus alkalosis

21 Clinical Application Metabolic acidosis Respiratory alkalosisMetabolic alkalosis