Page 1053 - Fundamentals of anatomy physiology

1040 Unit 5 Environmental Exchange 23. Describe the action of atrial and brain natriuretic peptides in the
r­eduction of sodium reuptake in the distal convoluted tubule.
14. Define what is the glomerular filtration rate. List three forces that de-
termine its value. 24. Describe two functions of countercurrent multiplication in the kidney.
25. Describe the micturition reflex.
15. Which structures of the urinary system are responsible for the trans-
port, storage, and elimination of urine? LEVEL 3 Critical Thinking and Clinical Applications

LEVEL 2 Reviewing Concepts 26. In a normal kidney, which of the following conditions would cause an
16. When the renal threshold for a substance exceeds its tubular maxi- increase in the glomerular filtration rate (GFR)? (a) constriction of the
afferent arteriole, (b) a decrease in the pressure of the glomerulus,
mum (a) more of the substance will be filtered, (b) more of the (c) an increase in the capsular hydrostatic pressure, (d) a decrease in
s­ ubstance will be reabsorbed, (c) more of the substance will be se- the concentration of plasma proteins in the blood, (e) a decrease in
creted, (d) the amount of the substance that exceeds the tubular maxi- the net glomerular filtration process.
mum will be found in the urine, (e) both a and d occur.
17. Sympathetic activation of nerve fibers in the nephron causes (a) the 27. John and Terry are in arid mountainous terrain but have just
regulation of glomerular blood flow and pressure, (b) the stimula- ­consumed the remainder of their water. They calculate that it will take
tion of renin release from the juxtaglomerular complex, (c) the direct approximately seven days for them to reach the nearest supply. John
stimulation of water and Na+ reabsorption, (d) all of these. thinks drinking their own urine will help them stay alive, whereas
18. Sodium reabsorption in the DCT and in the cortical portion of the Tony thinks it may kill them. Who is right and why?
collecting system is accelerated by the secretion of (a) ADH, (b) renin,
(c) aldosterone, (d) erythropoietin. 28. Why might people with hypertension (high blood pressure) be pre-
19. When ADH levels rise, (a) the amount of water reabsorbed increases, scribed angiotensin-converting enzyme inhibitors (ACE inhibitors)?
(b) the DCT becomes impermeable to water, (c) the amount of
water reabsorbed decreases, (d) sodium ions are exchanged for 29. Sylvia has kidney stones which have become lodged in the renal pel-
potassium ions. vis. Why might this lead to a reduction in GFR?
20. The control of blood pH by the kidneys during acidosis involves
(a) the secretion of hydrogen ions and reabsorption of bicarbonate 30. Mannitol is a sugar that is filtered, but not reabsorbed, by the kidneys.
ions from the tubular fluid, (b) a decrease in the amount of water What effect would drinking a solution of mannitol have on the vol-
reabsorbed, (c) hydrogen ion reabsorption and bicarbonate ion loss, ume of urine produced?
(d) potassium ion secretion.
21. Describe the role of antidiuretic hormone (ADH) in the formation of 31. The drug Diamox is sometimes used to treat mountain sickness.
concentrated urine. Diamox inhibits the action of carbonic anhydrase in the proximal
22. Describe how the urinary system supports cardiovascular function. convoluted tubule. Polyuria (the elimination of an unusually large
volume of urine) is a side effect associated with the medication.
Why does polyuria occur?

Clinical Case Wrap-Up

A Case of “Hidden” Bleeding This kidney is too
­damaged to heal. The sur-
Normally, when a kidney is injured, the urine appears geon quickly performs a
very bloody (hematuria). Mike has made very little left n­ ephrectomy (kidney
urine since his injury and massive blood loss, but the urine in his removal). If Mike survives this
catheter is clear. This reduces the initial suspicion of a renal injury. trauma, he will have to live
However, when the surgeon opens the left retroperitoneal with a solitary kidney. With the bleeding stopped, including the
space, he finds another large collection of free blood. When the “hidden” b­ leeding, the trauma team is finally able to sustain an
surgeon clears this blood away, the source of Mike’s continued adequate circulating blood volume.
bleeding becomes apparent. His left renal artery, renal vein, and
ureter have been completely torn away from the kidney at the 1. How could you tell from Mike’s x-rays that there is a high
hilum. The renal artery is briskly pumping what circulatory blood probability of renal injury?
volume is left into the retroperitoneal space, where it is walled off
from the abdominal space by the parietal peritoneum. Because 2. What do you think will happen to the glomerular filtration rate
the left ureter is completely torn from the damaged kidney, there (GFR) of Mike’s remaining right kidney if he survives this trauma?
is no visible blood in the urine.
See the blue Answers tab at the back of the book.