Unit #3 EXTRA Ready-To-Go Teaching Module After Class: Kidney Physiology

You've counseled Mr. Boulard about how to prevent recurrence of his hypokalemia. Which of the statements he makes indicates a need for further instruction?

"There's lots of potassium in regular table salt, so I'll just use more." Table salt is NaCl, not KCl. So ingesting it will not help prevent hypokalemia.

Site that drains the distal convoluted tubule.:

Collecting duct.

If the GFR is too low, needed substances may pass so quickly through the renal tubules that they are not absorbed and instead are lost in the urine.

False

Site of filtrate formation.:

Glomerulus.

Blood supply that directly receives substances from the tubular cells.:

Peritubular capillaries.

Site at which most of the tubular reabsorption occurs:

Proximal convoluted tubule.

The relatively long half-life of lipid-soluble hormones (steroid hormones) compared to water-soluble hormones is due in part to the way that these hormones are passed into the filtrate from the glomerular capillaries. From the list below select the best explanation for why lipid-soluble (steroid) hormones have a relatively long half-life.

Steroid hormones travel in the plasma on large transport proteins that cannot pass through the filtration membrane.

If the diameter of the efferent arterioles leading away from the glomerulus increases (vasodilation), which of the following is NOT likely to occur?

Systemic blood pressure will decrease.

The lab results of a newly admitted patient indicate renal impairment. How might this affect the dosing regimen of drugs that are excreted by the kidney?

The dosage or the dosage interval may need to be reduced. If the renal clearance of the drug is reduced by kidney disease, then drugs eliminated by the kidney may need to be given less often, in smaller amounts, or both. This appropriate regimen is often found in information provided by the drug manufacturer.

Mr. Boulard's blood pressure is quite high. How would this affect his nephron function? Choose the statement below that is most accurate.

The heart releases atrial natriuretic peptide that reduces sodium reabsorption at the kidney when blood pressure increases. Atrial natriuretic peptide is released by the heart in response to high blood pressure. It targets the nephron where it reduces the reabsorption of sodium, which leads to less water being reabsorbed. More water is lost in urine, reducing the blood volume and blood pressure.

Atrial natriuretic peptide inhibits sodium reabsorption.

True

Which of the following hormones acting on the collecting duct is most responsible for retaining sodium ions in the blood?

aldosterone

What is the effect of antidiuretic hormone on the cells of the collecting duct?

causes aquaporins to be inserted into the apical membranes

The presence of protein in the urine indicates which of the following?

damage to the filtration membrane

Upon reaching what point in the nephron is reabsorption (1) dependent upon the body's needs at the time and (2) regulated by hormones?

distal convoluted tubule Distal convoluted tubule (DCT) reabsorption only occurs under the influence of hormonal regulation.

Your patient's urinalysis shows a large amount of protein in the urine. This suggests a problem in the ____________

glomerulus If the glomerular capillary is damaged, large molecules such as proteins can pass through the filtration membrane and appear in the urine.

Alcohol acts as a diuretic because it ________.

inhibits the release of ADH

Which of the following is NOT a major urine formation process?

micturition Micturition is the process of urinating, releasing stored urine after it is formed.

Which structure is INCORRECTLY matched with a function?

nephron loop: reabsorption of urea Urea in the medullary interstitial fluid is secreted into the ascending thin limb of the nephron loop. This is followed by the reabsorption of urea in the collecting duct, which completes the process of urea recycling.

Where in the nephron does most solute reabsorption occur?

proximal convoluted tubule The proximal convoluted tubule (PCT) is where most reabsorption takes place.

Which of the following is the primary function of the juxtaglomerular complex?

releases chemical signals that regulate the rate of filtrate formation The macula densa cells and granular cells of the juxtaglomerular complex (JGC) release, respectively, vasoactive chemicals and renin. These chemical messengers lead to changes in vasomotor activity and Na+ reabsorption that affect the rate of filtrate formation and systemic blood pressure.

Since most patients with renal failure produce little or no urine, hemodialysis often involves removal of water from the blood. However, side-effects may develop if too much fluid is removed from the blood. Which of the following is NOT one of the potential side-effects?

vasoconstriction of afferent arterioles Vasoconstriction of the afferent arterioles occurs during times of high systemic blood pressure. This reflexive response lowers glomerular blood pressure and helps maintain normal glomerular filtration rates.