1. Principles of Anatomy and Physiology Thirteenth Edition Chapter 27 Fluid, Electrolyte, and Acid-Base Homeostasis Copyright © 2012 by John Wiley & Sons, Inc. Gerard J. Tortora Bryan H. Derrickson

2. Total body mass (female) (a) Distribution of body solids and fluids in average lean, adult female and male(b) Exchange of water among body fluid compartments Total body mass (male) 45% Solids 40% Solids 55% Fluids 60% Fluids 2/3 Intracellular fluid (ICF) 80% Interstitial fluid 1/3 Extracellular fluid (ECF) 20% Plasma Blood capillary Tissue cells Total body fluid Extracellular fluid

3. Metabolic water (200 mL) Ingested foods (700 mL) Ingested liquids (1600 mL) WATER GAIN GI tract (100 mL) Skin (600 mL) Kidneys (1500 mL) WATER LOSS 2500 2000 1500 1000 500 Volume of water (mL) Lungs (300 mL)

4. Dehydration Decreased flow of saliva Increased blood osmolarity Decreased blood volume Dry mouth and pharynx Stimulates osmoreceptors in hypothalamus Decreased blood pressure Increased renin release by juxtaglomerular cells of kidneys Increased angiotensin II formation Stimulates thirst center in hypothalamus Increases thirst Increases water intake Increases body water to normal level and relieves dehydration

5. Increased intake of NaCl Increased plasma concentrations of Na + and Cl – Increased osmosis of water from intracellular fluid to interstitial fluid to plasma Increased blood volume Increased stretching of atria of heart Increased release of atrial natriuretic peptide Decreased release of renin by juxtaglomerular cells Decreased formation of angiotensin II Reduced reabsorption of NaCl by kidneys Increased loss of Na + and Cl – in urine (natriuresis) Increased glomerular filtration rate Decreased release of aldosterone Increased loss of water in urine by osmosis Decreased blood volume

6. Excessive blood loss, sweating, vomiting, or diarrhea coupled with intake of plain water Decreased Na + concentration of interstitial fluid and plasma (hyponatremia) Decreased osmolarity of interstitial fluid and plasma Osmosis of water from interstitial fluid into intracellular fluid Water intoxication (cells swell) Convulsions, coma, and possible death

7. 142 Key: Blood plasma Interstitial fluid Intracellular fluid Extracellular fluids Na + K+K+ Ca 2+ Mg 2+ Cl – HCO 3 – HPO 4 2+ (organic) SO 4 2– Protein anions 175 150 125 100 75 50 25 0 mEq/liter 145 10 44 140 5 3 0.2 22 35 100 117 3 24 27 15 22 100 11 20 50 2

8. Some stimulus disrupts homeostasis by Blood pH (increase in H+ concentration) Receptors Control center Effectors Return to homeostasis when response brings blood pH or H + concentration back to normal As less H 2 CO 3 forms and fewer H + are present, blood pH increases (H + concentration decreases) Diaphragm contracts more forcefully and frequently so more CO 2 is exhaled Inspiratory area in medulla oblongata Central chemo- receptors in medulla oblongata Decreasing Nerve impulses Input Output Peripheral chemorece ptors in aortic and carotid bodies

9. Fluid in tubule lumen Intercalated cell in collecting duct Absorbed into peritubular capillary H+H+ ATP CA CO 2 + H 2 O H 2 CO 3 ADP H + + HCO 3 – Cl – HCO 3 – (new) (a) Secretion of H + Key: Proton pump (H + ATPase) in apical membrane HCO 3 – /Cl – antiporter in basolateral membrane Diffusion

10. Key: Proton pump (H + ATPase) in apical membrane HCO 3 – /Cl – antiporter in basolateral membrane Diffusion (b) Buffering of H + in urine H+H+ ATP ADP Interstitial fluid NH 3 + H + NH 4 + HPO 4 2– + H + H 2 PO 4 –