Explain the concept of a countercurrent multiplier system and how it works in the kidneys. What is the importance of this system to the function of the kidneys?

How do diuretics work to reduce excess fluid in the body?  Describe the mechanisms of action for three types of diuretics.

Explain the role of the countercurrent multiplier in a kidney.

How does the secretion of ADH affect urine volume and urine concentration?   What factors increase the release of ADH from the posterior pituitary gland?   How would you alter the secretion of aldosterone and ADH to reabsorb more sodium without reabsorbing large quantities of water from the filtrate?