25. The Urinary System

Tubular secretion occurs in the…

Which of the following is not a physiological process carried out by the kidneys?

a. Blood pressure regulation

b. Tubular reabsorption

c. Tubular secretion

d. Glomerular filtration

e. All of the above are physiological processes carried out by the kidneys.

Which of the following is false about the GFR?

a. The GFR averages about 120 ml/min.

b. The GFR increases when the afferent arteriole dilates.

c. The GFR decreases when the efferent arteriole constricts.

d. The GFR decreases when the afferent arteriole constricts

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

d. Filtrate flows from the renal corpuscle to the distal tubule, the nephron loop, the proximal tubule, and into the collecting system.

Describe the structure of the filtration membrane.

Which of the following substances would pass through the filtration membrane to become part of the filtrate under normal circumstances? (Circle all that apply.)

a. Sodium ions

b. Albumin

c. Glucose

d. Erythrocytes

e. Leukocytes

f. Amino acids

g. Urea

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

a. Sodium ions and glucose are cotransported into the proximal tubule cell by secondary active transport.

The route by which substances are reabsorbed by crossing through the cells of the renal tubule and collecting system is known as the:

a. paracellular route.

b. transcellular route.

c. primary active transport route.

d. facultative route.

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

b. The distal tubule reabsorbs sodium ions and secretes potassium and hydrogen ions in response to ADH.

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

c. Sodium ion reabsorption creates a gradient that helps drive the reabsorption of water and many other solutes from the proximal tubule.

Fill in the blanks: Glomerular hydrostatic pressure _____ filtration; colloid osmotic pressure and capsular hydrostatic pressure_____ filtration.

a. favors; favor

b. opposes; oppose

c. favors; oppose

d. opposes; favor

Dilute urine is produced when decreased levels of______ are secreted:

a. aldosterone

b. atrial natriuretic peptide

c. ADH

d. none of the above

Which of the following conditions does not contribute to the creation and/or maintenance of the medullary osmotic gradient?

a. The countercurrent exchanger of the vasa recta

b. The countercurrent multiplier of the nephron loops of cortical nephrons

c. The countercurrent multiplier of the nephron loops of juxtamedullary nephrons

d. The permeability of the medullary collecting system to urea and other ions

Fill in the blanks: The kidneys produce  _____ urine when the osmolarity of the body's fluids increases. They produce _____urine when the osmolarity of the body's fluids decreases.

Predict the effects the following scenarios would have on glomerular filtration:

a. Having excess proteins in the blood, increasing colloid osmotic pressure

Predict the effects the following scenarios would have on glomerular filtration:

b. Having low arterial blood pressure (hypotension)

Predict the effects the following scenarios would have on glomerular filtration:

c. Having high arterial blood pressure (hypertension)

Trace the pathway taken by a molecule of urea through the kidney from the glomerulus to the renal pelvis if the urea is recycled.

Why must the kidneys establish a concentration gradient in the interstitial fluid of the renal medulla in order to produce concentrated urine?

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

a. Blocking the action of aldosterone on the kidneys

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

b. Blocking the receptor for angiotensin-II on blood vessels and in the renal tubule cells

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

Mr. Wu is a patient with kidney disease who presents to your clinic for monitoring. You notice on his chart that his GFR was estimated through inulin administration to be about 35 ml/min. What does this tell you about the health of his kidneys? Mr. Wu is taking a medication that is normally excreted from the body in the urine. You order blood work and find that the concentration of this medication in his plasma is much higher than normal. How does his decreased GFR explain the elevated level of medication in his plasma?

Deana is a 4-year-old girl with a rare genetic defect that causes the Na+/glucose symporters in the proximal tubule to reabsorb fewer glucose and sodium ions than normal. Predict the effects this defect will have on the composition and volume of Deana's urine. Explain why you would expect to see increased activity of the tubuloglomerular feedback and the renin-angiotensin-aldosterone system in Deana's kidneys.

Explain how each of the drugs in question 1 from this section would lower blood ​pressure. (Connects to Chapter 17)​