The Urinary System: Glomerular Filtration

1. What force drives filtration at the glomerulus? __________

2. Glomerular filtration is a process of ___________ driven by the ______________________ of the blood.

3. Common components of the filtrate are divided into four categories on the CD program.

These include:

4. Blood pressure in the glomerulus is about _____ mmHg.

5. What two pressures oppose filtration and what are their values?

6. What is the normal net filtration pressure? _____ mmHg

7. With a glomerular filtration rate of 125 mL/min, how much plasma would be filtered per day? _________ In 24 hours? _________

8. In an exercising individual the afferent arteriole will dilate or constrict (circle one) to avoid excess fluid loss.

9. Two mechanisms that provide autoregulatory control over renal processes include:

10. High osmolarity (or high Na⁺ and Cl^-) in the ascending loop of Henle will cause afferent arterioles to dilate or constrict (circle one) by releasing _______________________.

11. In periods of extreme stress, the sympathetic nervous system will override autoregulation. An increase in sympathetic flow to the kidney will result in what two important effects that will aid maintenance of blood pressure?

The Urinary System: Early Filtrate Processing

1. What are the two reabsorption pathways through the tubular cell barrier?

2. How can we cause water to diffuse from the lumen into the interstitial space?

3. Transport of what ion could cause the diffusion in question #2?

4. Summarize reabsorption in the proximal tubule.

5. What percent of the filtrate is reabsorbed in the proximal tubule? ______%

6. The simple squamous epithelium cells of the thin descending loop are permeable to _______________ but impermeable to _______________.

7. The ascending limb of the loop of Henle is permeable to _________________ but impermeable to ________________.

8. What is the role of the loop of Henle?

9. What is the role of the Vasa Recta?

10. From the quiz section, what does furosemide do?

11. If you increase furosemide, what would happen to the following? (↑ or ↓)

a. _____ Na⁺/K⁺/2Cl^- cotransport

b. _____ Na⁺/K⁺/2Cl^- retained in tubule

c. _____ interstitial osmolarity

d. _____ water reabsorption in descending limb

e. _____ filtrate and volume flow

f. _____ urine output

g. _____ loss of body water and electrolytes

The Urinary System: Late Filtrate Processing

1. Name the two types of cells in the late distal tubules and cortical collecting ducts and describe their function.

2. Aldosterone is stimulated by an increase or decrease in what ions?

What does aldosterone increase in the basolateral membrane?

3. What does antidiuretic hormone (ADH) increase in the luminal membrane?

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

a. ADH? _____ dehydration, _____ overhydration (↑ or ↓)

b. Aldosterone? _____ dehydration, _____ overhydration (↑ or ↓)

5. Describe what moves out of the tubule and what the osmolarity would be in the following nephron segments:

a. Proximal tubule _____ moves out _____ mOsm

b. Descending limb _____ moves out _____ mOsm

c. Ascending limb _____ moves out _____ mOsm

d. Late distal tubule _____ moves out _____ mOsm

6. By the medullary collecting duct, only _____% of the filtrate remains.

7. Under the following conditions, report the levels of ADH and subsequent urine osmolarity and flow rate:

Hydration	ADH	Urine Osmolarity	Urine Volume
Normal
Dehydration
Overhydration

8. Urine with a:

a. “high normal osmolarity” and containing RBC’s and protein would indicate ________

b. very high osmolarity and glucose would indicate ____________________

c. very low osmolarity and high volume would indicate ______________________

9. An increase in plasma potassium levels would lead to what changes in the following? (↑ or ↓)

a. _____ Aldosterone levels

b. _____ Potassium excretion

c. _____ Sodium excretion

d. _____ Interstitial osmolarity

e. _____ Urine volume