25. Urinary System

Multiple Choice More than one choice may apply. Urine passes through the ureters by which mechanism? a. Ciliary action b. Gravity alone c. Peristalsis d. Suction

Which is reabsorbed by the proximal convoluted tubule cells? a. Na⁺, b. K⁺, c. amino acids, d. all of the above.

Glucose is not normally found in the urine because it a. does not pass through the walls of the glomerulus, b. is kept in the blood by colloid osmotic pressure, c. is reabsorbed by the tubule cells, d. is removed by the body cells before the blood reaches the kidney.

Multiple Choice More than one choice may apply. Which of the following is dependent on tubular secretion? a. Clearing penicillin from the blood b. Removal of nitrogenous wastes that have been reabsorbed c. Removal of excess potassium ions from the blood d. Control of blood pH

Filtration at the glomerulus is inversely related to a. water reabsorption, b. capsular hydrostatic pressure, c. arterial blood pressure, d. acidity of the urine.

Tubular reabsorption a. of glucose and many other substances is a Tₘ -limited active transport process, b. of chloride is always linked to the passive transport of Na⁺ , c. is the movement of substances from the blood into the nephron, d. of sodium occurs only in the proximal tubule.

Which of the following is/are true about ADH? a. It promotes obligatory water reabsorption, b. it is secreted in response to an increase in extracellular fluid osmolality, c. it causes insertion of aquaporins in the PCT, d. it promotes Na⁺ reabsorption.

Describe the mechanisms that contribute to renal autoregulation.

Trace the pathway a uric acid molecule takes from a glomerulus to the urethra. Name every gross or microscopic structure it passes through on its journey.

Describe the mechanisms of extrinsic regulation of GFR, and their physiological role.

What is the function of the glomerulus?

Describe what is involved in active and passive tubular reabsorption.

Explain how the peritubular capillaries are adapted for receiving reabsorbed substances.

Explain the difference between filtrate and urine.

Explain the process and purpose of tubular secretion.

Explain the important differences between blood plasma and glomerular filtrate, and relate the differences to the structure of the filtration membrane.

How does aldosterone modify the chemical composition of urine?

Explain why the filtrate becomes hypotonic as it flows through the ascending limb of the nephron loop. Also explain why the filtrate at the bend of the nephron loop (and the interstitial fluid of the deep portions of the medulla) is hypertonic.

Mrs. Bigda, a 60-year-old woman, was brought to the hospital by the police after falling to the pavement. She is found to have alcoholic hepatitis. She is put on a salt- and protein-restricted diet and diuretics are prescribed to manage her ascites (accumulated fluid in the peritoneal cavity). How will diuretics reduce this excess fluid? Name and describe the mechanisms of action of three types of diuretics. Why is her diet salt-restricted?

Why are renal failure patients undergoing dialysis at risk for anemia and osteoporosis? What medications or supplements could you give them to prevent these problems?

Two physiology students are having a disagreement about renal function. Dan says that the kidneys work harder when you eat a high-salt diet, whereas Peter says that they work harder when you drink lots of water. Who is right, and why?

Every day the kidneys filter nearly __________ of fluid from the bloodstream.

In what part of the nephron is plasma filtered?

The hydrostatic pressure in glomerular capillaries is the chief force pushing water and solutes out of the blood and across the filtration membrane.

An important factor directly affecting the glomerular filtration rate is __________.

Which substance would NOT normally be expected in urine?

All of the following are layers of the filtration membrane in the glomerular membrane EXCEPT the __________.

Which process results in increased blood pressure in response to hormone release?

If the efferent arteriole constricts while the afferent arteriole remains unchanged, the glomerular filtration rate __________.

What structure(s) is/are part of the juxtaglomerular complex and act(s) as a mechanoreceptor, sensing blood pressure in the afferent arteriole?

The reason glucose is detected in the urine of individuals with uncontrolled diabetes mellitus is that __________.

Water can leave the ascending limb of the nephron loop.

The descending limb of the nephron loop is relatively impermeable to solutes and freely permeable to water.

How is Na⁺ reabsorbed?

When the concentration of ADH increases, __________.

Tubular secretion is important for all EXCEPT which of the following?

All of the following functions are carried out in the renal tubules EXCEPT __________.

Which of the following is the countercurrent multiplier in the kidney?

Which nephron capillary bed specializes in forming concentrated urine?

Urea transport out of the medullary collecting duct is enhanced by __________.