Anatomy & Physiology II

Chapter 24

Fluids, Electrolytes, & Acid-Base Balance

1.      Secretion of potassium into the urine:
            a. Is decreased by aldosterone
            b. Is associated with the reabsorption of sodium from the distal tubules and collecting ducts
            c. Is minimal because humans ingest very little potassium
            d. Is increased with elevated levels of ADH
            e. Is increased in the presence of atrial natriuretic hormone

2. Dehydration would cause:
           a. Fluid to shift from the ECF to the ICF
           b. Decreased secretion of ADH
           c. Increased thirst
           d. Decreased levels of aldosterone
           e. All of the above

3. When the pH of body fluids begins to fall:
           a. Proteins will release a hydrogen ion from the carboxyl group
           b. Proteins will release a hydrogen ion from the amino group
           c. Proteins will bind a hydrogen at the carboxyl group
           d. Proteins will bind a hydrogen at the amino group
           e. None of the above

4. When the pH of the extracellular fluid declines:
          a. The kidneys excrete more sodium ions
          b. The kidneys excrete more bicarbonate ions
          c. The kidneys retain more potassium ions
          d. The pH of the urine increases
          e. The kidneys reabsorb less water

5. What affect would a decrease in pH have on the amount of potassium ion in the urine?
         a. It would cause an increase in the amount of potassium in the urine
         b. It would cause a decrease in the amount of potassium in the urine
         c. It would have no effect on the amount of potassium in the urine

6. A mountain climber at high altitude may lose consciousness as the result of:
          a. Respiratory acidosis                                 c. Metabolic acidosis
          b. Respiratory alkalosis                                d. Metabolic alkalosis

7.   Which of the following cations is most concentrated in the intracellular fluid? 
          a. Ca²⁺                                                 d. Na⁺
          b. Fe²⁺                                                 e. K⁺
          c.NH⁴⁺    

8. Aldosterone receptors are found on cells of:
          a. The posterior pituitary                                     d. The descending loop of nephron
          b. The ascending loop of nephron                     e. The proximal convoluted tubule
          c. The distal convoluted tubule  

9.  The pH of the intracellular fluid is buffered mainly by:
          a. Bicarbonate                                                     d. Carbonic acid
          b. Protein                                                              e. Ammonium ions
          c. Phosphates   

10. The bicarbonate buffer system would not work very well in the human body if not for the action of the respiratory system, which:
           a. Supplies the buffer system with CO₂ 
           b. Supplies the buffer system with O₂
           c. Expels HCO₃^- produced by the buffer system
           d. Expels H⁺ produced by the buffer system
           e. Expels CO₂ produce by the buffer system

11. The limiting pH is a value below which:
           a. Human life cannot be maintained
           b. Hydrogen ions cannot be reabsorbed from the tubular fluid
           c. Hydrogen ions cannot be secreted into the tubular fluid
           d. The bicarbonate buffer system no longer works
           e. Hydrogen ions must be buffered by ammonia

12. Because of carbonic anhydrase on the brush borders of the kidney tubules:
          a. The kidneys eliminate almost as much CO2 as the lungs do
          b. The urine is normally free of bicarbonate ions
          c. The urine contains a high concentration of bicarbonate ions
          d. Bicarbonate ions are rapidly reabsorbed by the kidney tubules
          e. The pH of the urine is normally slightly basic

13. The volume of water in a cell is mainly governed by the amount of _?_ in the cytoplasm.
         a. K+                                          d. HCO3-
         b. Protein                                   e. Cl-
         c. Na+

14. If you could trace the hydrogen ions removed from the blood andexcreted in the urine, most of them would be part of the _?_ of the urine.
          a. NaH₂PO₄                                            d. Urea
          b. NH₄Cl                                                   e. H₂O
          c. HCO₃^-

 15. The collecting ducts of the kidney have intercalated cells which can:
           a. Override the limiting pH
           b. Secrete aldosterone in response to hyponatremia
           c. Secrete renin and activate the angiotensin-aldosterone system
           d. Reabsorb K⁺ from the urine
           e. Secrete K⁺ into the urine

16. Sympathetic signals from the thirst center of the hypothalamus will?

17. Name three factors that stimulate short-term satiation of thirst.

18. What is the physiological difference between hypovolemia (volume depletion) and true dehydration? What will the body's hormonal response be to each?

19. The most significant ion in determining total body water and distribution is _?_.

20. What is the specific cellular response to aldosterone?

21. What are the target cells of ADH and what is their specific response to ADH?

22. Phosphates are concentrated in the ICF, while calcium ions are either pumped out of the cell or stored in the sarcoplasmic reticulum. Why is it important to keep these ions apart?

23. Name two factors that determine the amount of acid or base that can be neutralized by a buffer system.

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