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Muscular System: Tubular Reabsorption and Secretion

Answer Key

1. _______________ is the movement of water and valuable solutes from the filtrate in the renal tubules into the blood. In which part of the renal tubule does this take place? In which part of the renal tubules does most of it take place?

1. ______________ is the movement of selected solutes from the blood of the peritubular capillaries into the renal tubule for excretion.

1. What is the purpose of reabsorption in the kidney tubule?

1. Name 2 pathways whereby water and solutes can be reabsorbed from the lumen of the renal tubule to the blood of the peritubular capillaries. Which pathway is the most commonly used?

1. How does the Na-K pump affect the reabsorption of sodium and water in the renal tubule?

1. Consuming a salty meal would increase / decrease water reabsorption from the filtrate.

1. How does sodium reabsorption by the proximal tubule drive the reabsorption of other solutes such as glucose?

1. Explain the concept of transport maximum in your own words.

1. Considering the concept of transport maximum, why would a patient with uncontrolled diabetes mellitus have glucose in their urine?

1. What effect does aldosterone have on the membranes of the kidney tubule, and how does this effect sodium reabsorption?

1. How does ADH (antidiuretic hormone) affect the collecting duct membrane, and how does this influence water reabsorption?

1. In dehydration and overhydration, what would be the levels of:

   1. ADH ___________ dehydration ___________ overhydration (↑ or ↓)

   2. Aldosterone __________ dehydration ____________ overhydration (↑ or ↓)

1. For each part of the renal tubule listed, tell whether reabsorption, secretion, or both processes happen there.

   1. Proximal tubule

   2. Nephron loop

   3. Distal tubule

   4. Collecting duct

1. List at least 4 solutes that are secreted into the filtrate. With these items in mind, explain why secretion is so important in generating urine.

1. Compare and contrast reabsorption and secretion for the following items: