Drugs that treat hypertension, or high blood pressure, have the following actions. Discuss the specific effect that each drug will have on the kidneys.


c. Blocking the Na+/Cl−/2K+ transport pumps in the thick ascending limb of the nephron loop

Verified step by step guidance

1. Understand the role of the Na+/Cl−/2K+ transport pumps in the thick ascending limb of the nephron loop. These pumps are responsible for reabsorbing sodium, chloride, and potassium ions from the filtrate back into the blood.
2. Recognize that blocking these transport pumps will lead to a decrease in the reabsorption of these ions, particularly sodium, which is a key player in water reabsorption due to osmosis.
3. Consider the effect of decreased sodium reabsorption on the osmotic gradient in the renal medulla. This will reduce the kidney's ability to concentrate urine, leading to increased urine output (diuresis).
4. Understand that increased urine output will result in a decrease in blood volume, which can help lower blood pressure, as there is less fluid in the circulatory system.
5. Reflect on the potential side effects of this mechanism, such as electrolyte imbalances, due to the loss of sodium, chloride, and potassium in the urine.

Key Concepts

Nephron Structure and Function

The nephron is the functional unit of the kidney, responsible for filtering blood and forming urine. It consists of various segments, including the glomerulus, proximal tubule, loop of Henle, distal tubule, and collecting duct. Each segment plays a specific role in reabsorbing water, electrolytes, and nutrients, as well as excreting waste products.

Na+/Cl−/2K+ Transport Pumps

The Na+/Cl−/2K+ transport pumps, also known as the Na-K-2Cl cotransporter, are located in the thick ascending limb of the nephron loop. These pumps are crucial for reabsorbing sodium, potassium, and chloride ions from the filtrate back into the bloodstream, which helps regulate fluid balance and blood pressure. Blocking these pumps can lead to increased excretion of these ions and water.

Diuretics and Their Mechanism of Action

Diuretics are medications that promote the excretion of water and electrolytes through urine, primarily by acting on the kidneys. By blocking specific transport mechanisms, such as the Na+/Cl−/2K+ transport pumps, diuretics reduce the reabsorption of sodium and chloride, leading to increased urine output. This action is beneficial in treating hypertension by lowering blood volume and, consequently, blood pressure.