31.  Increased ADH secretion could be stimulated by which of the following situations?  
A.  increased renal blood flow
B.  increased blood osmolality
C.  increased atrial natriuretic hormone production
D.  increased blood pressure
E.  decreased blood osmolality

32.  Atrial natriuretic hormone increases  
A.  urine volume.
B.  ADH secretion.
C.  aldosterone secretion.
D.  the reabsorption of sodium ions.
E.  blood volume.

33.  What characteristic of the plasma membrane is responsible for maintaining the difference between intracellular and extracellular fluid?  
A.  presence of channels in the membrane
B.  presence of lipids in the membrane
C.  being selectively permeable
D.  high sodium concentration inside the cell

34.  The composition of extracellular fluid has little affect on intracellular fluid amounts.  
FALSE

35.  Which of the following would be expected to cause hyponatremia?  
A.  high intake of sodium
B.  increased aldosterone production
C.  increased urine output
D.  decreased aldosterone production
E.  decreased ADH production

36.  Oversecretion of aldosterone causes  
A.  hyperkalemia.
B.  hypercalcemia.
C.  hypernatremia.
D.  increased urine volume.
E.  hyponatremia.

37.  Chloride ions  
A.  are cations.
B.  are found only inside cells.
C.  are part of the DNA molecule.
D.  are regulated with Na+.
E.  are not found in extracellular fluid.

38.  Decreased extracellular potassium levels cause  
A.  cells to become more excitable.
B.  hyperpolarization of cell membranes.
C.  more action potentials to be generated.
D.  increased permeability of cell membranes.
E.  hypopolarization of cell membranes.

39.  Which of the following statements concerning potassium ions is false?  
A.  An increase in the extracellular potassium ion concentration leads to depolarization.
B.  Potassium ions are secreted into the nephron by the distal convoluted tubule.
C.  When aldosterone levels are high, potassium secretion is low.
D.  Aldosterone secretion is stimulated by high blood levels of potassium ions.
E.  None of these choices is false.

40.  Potassium levels in the body are regulated by  
A.  ADH.
B.  PTH.
C.  calcitonin.
D.  aldosterone.
E.  insulin.