1. Which of the following statements about aldosterone is NOT correct? Aldosterone is stimulated by decreased plasma sodium levels and increased plasma potassium levels. Aldosterone increases the number of passive sodium channels in the luminal membrane of the distal tubule and collecting duct, thus aiding sodium reabsorption. Aldosterone increases sodium reabsorption by increasing the number of Na+-K+ ATPase pumps in the luminal membrane of the proximal tubule. Aldosterone is produced in the adrenal cortex. 2. Which of the following statements about ADH (antidiuretic hormone) is correct? ADH is released by the posterior pituitary gland. ADH inserts water channels into the luminal membrane of the proximal tubules. ADH is synthesized by the adrenal gland and works in the kidney. ADH would increase urine volume. 3. In severe dehydration or blood loss, what would be the levels of ADH and what would be the urine flow rate? ADH – high; high urine flow rate (16 ml/min) ADH – low; low urine flow rate (0.25 ml/min) ADH – high; low urine flow rate (0.25 ml/min) ADH – low; high urine flow rate (16 ml/min)
