This chapter should help the student to:

• List the organs of the urinary system and describe the role of each in the system’s functions.
  
• Identify the structures and regions visible in a frontal section of a kidney and describe their functions.
  
• Describe the structure, function, and location of each component of a nephron and identify these components in histologic sections.
  
• Describe the function of the juxtaglomerular apparatus and identify its components.
  
• Trace the flow of blood through the kidney and identify renal vessels in histologic sections.
  
• Trace the flow of urinary filtrate from Bowman’s space to the exterior, naming in order the tubules and components of the urinary tract and describing any changes in filtrate composition and epithelial lining that occur in each component.
  
• Describe the kidney’s endocrine functions and the hormonal regulation of renal function.

1. Name the organs of the urinary system (I.A.1 and 2) and describe their roles in the system’s functions (I.B).

2. Sketch a frontal section of the kidney (Fig. 19–1) and label the following:

1. 
   

   Capsule (II.A)

   
   
2. 
   

   Cortex (II.A.3)

   
   
3. 
   

   Medulla (II.A.4)

   
   
4. 
   

   Medullary pyramids (II.A.4)

   
   
5. 
   

   Medullary rays (II.A.5)

   
   
6. 
   

   Renal columns (Fig. 19–1)

   
   
7. 
   

   Major calyx (I.A.1.a)

   
   
8. 
   

   Minor calyx (I.A.1.a)

   
   
9. 
   

   Renal papilla (II.A.4)

   
   
10. 
    

    Renal pelvis (I.A.1.a)

    
    
11. 
    

    Renal sinus (I.A.1.a)

    
    
12. 
    

    Hilum (I.A.1.a)

    
    
13. 
    

    Renal artery and vein (I.A.2.a)

    
    
14. 
    

    Interlobar artery and vein (II.E)

    
    
15. 
    

    Arcuate artery and vein (II.E)

    
    
16. 
    

    Interlobular artery and vein (II.E)

    
    
17. 
    

    Renal lobe (II.A.6)

    
    
18. 
    

    Renal lobule (II.A.7)

3. Sketch a nephron, label its major components, and show which components lie in the cortex and which in the medulla (II.B.1–5; Fig. 19–4).

4. Sketch a renal corpuscle and label the following:

1. 
   

   Glomerulus (II.B.1.a)

   
   
2. 
   

   Visceral and parietal layers of Bowman’s capsule (II.B.1.b)

   
   
3. 
   

   Urinary space (II.B.1.b)

   
   
4. 
   

   Afferent and efferent arterioles (II.B.1.f)

   
   
5. 
   

   Vascular pole (II.B.1.d)

   
   
6. 
   

   Urinary pole (II.B.1.e)

   
   
7. 
   

   Proximal convoluted tubule (II.B.2)

   
   
8. 
   

   Mesangial cells (II.B.1.a)

5. Sketch the ultrastructure of a portion of the glomerular filtration barrier (Fig. 19–2) and label the following:

1. 
   

   Glomerular capillary lumen

   
   
2. 
   

   Glomerular capillary endothelial cell

   
   
3. 
   

   Endothelial fenestrae

   
   
4. 
   

   Fused basal laminae

   
   
5. 
   

   Pedicels

   
   
6. 
   

   Filtration slits (slit pores)

   
   
7. 
   

   Diaphragms covering filtration slits

   
   
8. 
   

   Urinary space

6. Describe the role of mesangial cells in maintaining filtration barrier integrity (II.B.1.f).

7. Compare proximal and distal convoluted tubules in terms of:

1. 
   

   Location in the kidney (II.B.2 and 4)

   
   
2. 
   

   Epithelial lining (height, microvilli, mitochondria, staining, lateral and basal plasma membrane infoldings; II.B.2 and 4)

   
   
3. 
   

   Luminal diameter (II.B.2 and 4)

   
   
4. 
   

   Substances absorbed from or secreted into filtrate (II.B.2 and 4)

8. What is the general function of the loop of Henle (II.B.3.b)?

9. Compare the ascending and descending loop of Henle in terms of the type of convoluted tubules its thick portions resemble, the epithelial lining of its thin portions, and permeability to water (II.B.2, 3.b.[1],[2], and 4).

10. Compare cortical and juxtamedullary nephrons in terms of their numbers, their roles (active versus passive) in establishing medullary hypertonicity, and the length of their loops (II.B.5).

11. Compare collecting tubules and ducts (II.C.1 and 2) with convoluted tubules (II.B.2 and 4) in terms of location and epithelia (epithelial height variation, cytoplasmic staining intensity, and intercellular border visibility).

12. Describe the juxtaglomerular apparatus (II.D) in terms of its components and their locations. Which cells secrete renin?

13. Trace the flow of blood from the renal arteries to the glomerular capillaries (II.E).

14. Compare the paths taken to the renal vein by blood leaving the cortical and the juxtamedullary glomeruli. (Hint: one path includes peritubular capillaries and stellate veins; the other includes the vasa recta; II.E.)

15. Compare the vasa recta (II.E) with the thin loops of Henle (II.B.3) from juxtamedullary nephrons in terms of location, contents, epithelial type and thickness, and countercurrent function.

16. Compare aldosterone (II.B.4) and antidiuretic hormone (ADH; II.C.2) in terms of:

1. 
   

   Site of synthesis and secretion

   
   
2. 
   

   Stimulus for secretion

   
   
3. 
   

   Site of action in the kidney

   
   
4. 
   

   Role in kidney function

17. Beginning with the stimulus for renin production, diagram the cascade that yields angiotensin II and explain its role in renal function (II.D).

18. Trace the flow of filtrate from the urinary (Bowman’s) space to a minor calyx, naming, in order, the tubules through which the fluid flows. Describe any changes in fluid composition (substances added or removed), volume, and osmolarity (tonicity) that occur in each tubule segment (II.F; Fig. 19–3).

19. Describe the structural features of the walls of the renal calyces (III), renal pelvis (III), ureters (IV), and urinary bladder (V).

20. Name—in order, from bladder to exterior—the parts of the male urethra and the epithelial lining of each part (VI.A.1–3).