2. I. pH of Body Fluids water ionizes to form protons (H + ) and proton acceptors (OH - ) A. Remember that to an extent water ionizes to form protons (H + ) and proton acceptors (OH - ) 1. The pH of a solution is determined by the measure of the solution’s H+ ion concentration. it has a higher H + concentration than OH - concentration a. When a solution is acidic it has a higher H + concentration than OH - concentration it has a higher concentration of OH - concentration than H + concentration b. When a solution is basic it has a higher concentration of OH - concentration than H + concentration H2OH2O H + + OH -

3. many different changes, both internal and external, effect pH. 2. In our bodies, many different changes, both internal and external, effect pH.

4. II. Controlling pH in our Bodies narrow pH 7.35-7.45 A. The pH of the blood needs to be within a narrow pH range of 7.35-7.45. the buffer system, the respiratory system, and the urinary system. 1. There are three ways that the blood pH is maintained: the buffer system, the respiratory system, and the urinary system. because of (carbon dioxide) CO 2 level differences and filtering in the kidneys. 2. The pH of blood differs in arteries and veins: because of (carbon dioxide) CO 2 level differences and filtering in the kidneys.

5. of a chemical reaction that occurs between CO 2 and water (H 2 O). B. The blood in veins is slightly more acidic because of a chemical reaction that occurs between CO 2 and water (H 2 O). all of the cells undergoing cellular respiration around the blood capillaries. 1. CO 2 is released into the veins from all of the cells undergoing cellular respiration around the blood capillaries.

6. *Carbonic anhydrase is an enzyme necessary to speed up the rate of this reaction.

8. the amount of carbonic acid in the blood will decrease the pH of the blood 2. If you hold your breath the amount of carbonic acid in the blood will decrease the pH of the blood. condition in which there is an excessive proportion of acid in the blood Acidosis – condition in which there is an excessive proportion of acid in the blood condition in which there is an excessive proportion of alkali (base) in the blood Alkalosis – condition in which there is an excessive proportion of alkali (base) in the blood

9. Buffers C. Buffers in the blood work to make sure the pH remains at homeostasis. compound that combines with an acid or with a base to form a weaker acid or base, thereby lessening the change in hydrogen-ion concentration that would occur without the buffer Buffer – compound that combines with an acid or with a base to form a weaker acid or base, thereby lessening the change in hydrogen-ion concentration that would occur without the buffer the amount of H + ions in the solution. The higher the concentration of H + ions, the stronger the acid. 1. The strength of an acid depends on the amount of H + ions in the solution. The higher the concentration of H + ions, the stronger the acid. the amount of *OH - ions in the solution. The higher the concentration of OH - ions in the solution, the stronger the base. The strength of a base depends on the amount of *OH - ions in the solution. The higher the concentration of OH - ions in the solution, the stronger the base. *Or any proton-accepting compound

10. acidsbuffering the strong acid (i.e. Hydrochloric acid, HCl) to make a much weaker acid and sodium chloride. 2. Sodium bicarbonate (NaHCO 3 ) buffers extreme acids by buffering the strong acid (i.e. Hydrochloric acid, HCl) to make a much weaker acid and sodium chloride. basesbuffering the strong base (i.e. Sodium hydroxide, NaOH) to make NaHCO 3 and water. Carbonic acid buffers extreme bases by buffering the strong base (i.e. Sodium hydroxide, NaOH) to make NaHCO 3 and water. weak acids buffering the weak acid to form a weaker acid and sodium lactate. Sodium bicarbonate buffers weak acids by buffering the weak acid to form a weaker acid and sodium lactate.

11. they can remove both excess acids and excess base. D. The kidneys are the most efficient organs for regulating blood pH because they can remove both excess acids and excess base. acidify 4.8 1. Kidneys usually acidify urine to a pH of approximately 4.8. 2(While still excreting acid) 2. The kidneys conserve sodium bicarbonate (NaHCO 3 ) in 2 ways. (While still excreting acid)

12. III. pH Imbalances 201 A. In humans the acid-base balance needs to be maintained at the proper ratio of 20 NaHCO 3 to 1 H 2 CO 3. the levels of H 2 CO 3 can drop, raising the pH of the blood to normal levels. 1. CO 2 is expelled in the respiratory and urinary systems so that the levels of H 2 CO 3 can drop, raising the pH of the blood to normal levels. protons from the NH 2 will not raise the acid (lower pH) level of the blood. 2. Proteins that contain an –NH 2 group are expelled in the urinary system so that protons from the NH 2 will not raise the acid (lower pH) level of the blood.

13. metabolic acidosismetabolic alkalosis B. Metabolic disturbances in acid-base balance result in metabolic acidosis and metabolic alkalosis. a bicarbonate deficiency caused by renal failure/disease, uncontrolled diabetes, prolonged diarrhea, or the ingestion of toxic chemicals like antifreeze (ethylene glycol) or wood alcohol (methanol) 1. Metabolic acidosis can be caused by a bicarbonate deficiency caused by renal failure/disease, uncontrolled diabetes, prolonged diarrhea, or the ingestion of toxic chemicals like antifreeze (ethylene glycol) or wood alcohol (methanol). bicarbonate excess. This can be the result of diuretic therapy, loss of gastric juice due to vomiting or suction or from certain diseases 2. Metabolic alkalosis can be caused by bicarbonate excess. This can be the result of diuretic therapy, loss of gastric juice due to vomiting or suction or from certain diseases.

14. C. Respiratory disturbance an excess of H 2 CO 3 resulting from slow breathing that will increase the concentration of CO 2 in the arteries. This can happen due to depressed breathing due to anesthesia, drugs, or pulmonary disease. 1. Respiratory acidosis can be caused by an excess of H 2 CO 3 resulting from slow breathing that will increase the concentration of CO 2 in the arteries. This can happen due to depressed breathing due to anesthesia, drugs, or pulmonary disease. an H 2 CO 3 deficit resulting from excessive loss of CO 2 due to hyperventilating. Hyperventilation can occur due to nervousness, overinflation of patients on ventilators, or a hepatic coma. 2. Respiratory alkalosis can be caused by an H 2 CO 3 deficit resulting from excessive loss of CO 2 due to hyperventilating. Hyperventilation can occur due to nervousness, overinflation of patients on ventilators, or a hepatic coma.

15. a. The removal of CO 2 occurs when: 1. CO 2 leaves the blood and enters the distal tubules of the kidneys 2. In the kidneys it reacts with H 2 O to form H 2 CO 3 3. A proton leaves H 2 CO 3 and enters the urine leaving HCO 3 - to bind with a Na + ion to form NaHCO 3 4. The H + -ion makes a weak acid (NaH 2 PO 4 ) and is excreted with urine.

16. b. The removal of amino groups (-NH 2 ) when: 1. Breaking down proteins result in the release of amino acids into blood. 2. -NH 2 leaves the blood and enters the distal tubules of the kidneys 3. A proton joins –NH 2 to form NH 3. NH 3 then goes into urine. 4. In urine, NaCl dissociates and a Cl- ion joins NH 3 to make NH 3 Cl - (a base) 5. H 2 CO 3 releases a H+ ion that enters the urine to join NH 3 Cl- to form NH 4 Cl to be excreted with the urine 6. HCO 3 in the kidneys bonds with Na + to make NaHCO 3