Chapter 44: Osmoregulation and Excretion MULTIPLE CHOICE 1) A marine sea star was mistakenly placed in freshwater and it died. What is the most likely explanation for its death? A) The sea star was stressed and needed more time to adapt to new conditions. B) The sea star is hypertonic to the freshwater, and it could not osmoregulate. C) The osmoregulatory system of the sea star could not handle the change in ionic content presented by the freshwater. D) The contractile vacuoles used to regulate water content ruptured in the freshwater. E) The cells of the sea star dehydrated and lost the ability to metabolize. ANS: B
TOP: Concept 44.1
2) Organisms categorized as osmoconformers are most likely A) terrestrial. B) marine. C) amphibious. D) found in freshwater streams. E) found in freshwater lakes. ANS: B
TOP: Concept 44.1
3) The body fluids of an osmoconformer would be ____ with its ____ environment. A) hypertonic; freshwater B) isotonic; freshwater C) hyperosmotic; saltwater D) isoosmotic; saltwater E) hypoosmotic; saltwater ANS: D
TOP: Concept 44.1
4) Compared to the seawater around them, most marine invertebrates are A) hyperosmotic. B) hypoosmotic. C) isoosmotic. D) hyperosmotic and isoosmotic. E) hypoosmotic and isoosmotic. ANS: C
TOP: Concept 44.1
5) Which feature of osmoregulation is found in both marine and freshwater bony fish? A) loss of water through the gills B) gain of salt through the gills C) loss of water in the urine D) no drinking of water E) gain of water through food ANS: E
TOP: Concept 44.1
6) In addition to their role in gas exchange, fish gills are also directly involved in A) digestion. B) osmoregulation.
C) thermoregulation. D) the excretion of uric acid. E) the release of atrial natriuretic proteins. ANS: B
TOP: Concept 44.1
7) All of the following represent adaptations by terrestrial animals to drying conditions except A) anhydrobiosis. B) salt glands. C) efficient kidneys. D) impervious surfaces. E) increased thirst. ANS: B
TOP: Concept 44.1
8) The digestion and utilization of which nutrient creates the greatest need for osmoregulation by the kidneys? A) protein B) starch C) fat D) oil E) cellulose ANS: A
TOP: Concept 44.2
9) Which of the molecules shown in the figure below represents urea?
A) B) C) D) E)
A B C D E
ANS: B
TOP: Concept 44.2
10) Where and from what compound(s) is urea produced? A) liver from NH3 and CO2 B) liver from glycogen C) kidneys from glucose D) kidneys from glycerol and fatty acids E) bladder from uric acid and H2O ANS: A
TOP: Concept 44.2
11) Which of the following is true of urea? It is A) insoluble in water. B) more toxic to human cells than ammonia. C) the primary nitrogenous waste product of humans. D) the primary nitrogenous waste product of most birds. E) the primary nitrogenous waste product of most aquatic invertebrates. ANS: C
TOP: Concept 44.2
12) Which of the following is true of ammonia? A) It is soluble in water. B) It can be stored as a precipitate. C) It has low toxicity relative to urea. D) Only A and C are true. E) A, B, and C are true. ANS: A
TOP: Concept 44.2
13) Which of the following is not a function of the liver? A) storage of glycogen B) secretion of urea C) production of plasma proteins D) removal of glucose from the blood E) detoxification of chemical poisons in the blood ANS: B
TOP: Concept 44.2
14) The advantage of excreting wastes as urea rather than as ammonia is that A) urea can be exchanged for Na+. B) urea is less toxic than ammonia. C) urea requires more water for excretion than ammonia. D) urea does not affect the osmolar gradient. E) less nitrogen is removed from the body. ANS: B
TOP: Concept 44.2
15) What is the main nitrogenous waste excreted by birds? A) ammonia B) nitrate C) nitrite D) urea E) uric acid ANS: E
TOP: Concept 44.2
16) Which of the following is a nitrogenous waste that requires hardly any water for its excretion? A) amino acid B) urea C) uric acid D) ammonia E) nitrogen gas ANS: C
TOP: Concept 44.2
17) What is the process called by which materials are returned to the blood from the nephron fluid? A) filtration B) ultrafiltration C) selective reabsorption D) secretion E) active transport ANS: C
TOP: Concept 44.3
18) Which organism(s) has excretory structures known as protonephridia? A) flatworms B) earthworms C) insects D) vertebrates E) both C and D ANS: A
TOP: Concept 44.3
19) Which organism(s) has excretory organs known as Malpighian tubules? A) earthworms B) flatworms C) insects D) jellyfish E) both A and B ANS: C
TOP: Concept 44.3
20) Which of the following mechanisms for osmoregulation or nitrogen removal is incorrectly paired with its corresponding animal? A) metanephridium-earthworm B) Malpighian tubule-insect C) kidney-frog D) flame bulb-snake E) direct cellular exchange-marine invertebrate ANS: D
TOP: Concept 44.3
21) Which of the following excretory systems is partly based on the filtration of fluid under high hydrostatic pressure? A) flame-bulb system of flatworms B) protonephridia of rotifers C) metanephridia of earthworms D) Malpighian tubules of insects E) kidneys of vertebrates ANS: E
TOP: Concept 44.3
22) What is the functional unit of the kidney? A) cortex B) vasa recta C) nephron D) bladder E) glomerulus ANS: C
TOP: Concept 44.4
23) The transfer of fluid from the glomerulus to Bowman's capsule A) results from active transport. B) transfers large molecules as easily as small ones. C) is very selective as to which small molecules are transferred. D) is mainly a consequence of blood pressure force-filtering the fluid. E) usually includes the transfer of red blood cells to the nephron tubule. ANS: D
TOP: Concept 44.4
24) Which part of the vertebrate nephron consists of capillaries? A) glomerulus B) loop of Henle C) distal tubule D) Bowman's capsule E) collecting duct ANS: A
TOP: Concept 44.4
25) Which of the following normally contains blood? A) vasa recta B) Bowman's capsule C) loop of Henle D) proximal tubule E) collecting duct ANS: A
TOP: Concept 44.4
Refer to the figure below, a diagram of a renal tubule, to answer the following questions.
26) In which region would filtration occur? A) I
B) C) D) E)
III IV V VII
ANS: A
TOP: Concept 44.4
27) In which region would urine become more concentrated? A) I B) III C) IV D) V E) VII ANS: E
TOP: Concept 44.4
28) In which region would nutrients be actively transported to the blood? A) I B) II C) IV D) V E) VI ANS: B
TOP: Concept 44.4
29) Which part directly leads to the area where membranes become permeable to urea? A) III B) IV C) V D) VI E) VII ANS: E
TOP: Concept 44.4
30) What substance is secreted by the proximal-tubule cells and prevents the pH of urine from becoming too acidic? A) bicarbonate B) salt C) glucose D) ammonia E) HCl ANS: D
TOP: Concept 44.4
31) Which structure passes urine to the renal pelvis? A) loop of Henle B) collecting duct C) Bowman's capsule D) proximal tubule E) glomerulus ANS: B
TOP: Concept 44.4
32) Which structure possesses specialized cells called podocytes? A) loop of Henle B) collecting duct
C) Bowman's capsule D) proximal tubule E) glomerulus ANS: C
TOP: Concept 44.4
33) Which structure is the first section of the nephron tubule into which the filtrate enters? A) loop of Henle B) collecting duct C) ureter D) proximal tubule E) glomerulus ANS: D
TOP: Concept 44.4
34) Which structure descends deep into the renal medulla only in juxtamedullary nephrons? A) loop of Henle B) collecting duct C) Bowman's capsule D) proximal convoluted tubule E) glomerulus ANS: A
TOP: Concept 44.4
35) All of the following are functions of the mammalian kidney except A) water reabsorption. B) filtration of blood. C) excretion of nitrogenous waste. D) regulation of salt balance in the blood. E) production of urea as a waste product of protein catabolism. ANS: E
TOP: Concept 44.4
36) Which one of the following structures is found in birds and mammals but not in other vertebrates? A) juxtamedullary nephrons B) nephrons C) urethra D) ureter E) Bowman's capsule ANS: A
TOP: Concept 44.4
37) Which of the following is not true concerning transport epithelia involved in water balance? A) One surface of the epithelium faces the outside environment directly or indirectly. B) The epithelium is a semipermeable barrier. C) The surface area is small, which prevents excessive water loss. D) The epithelium regulates the movement of solutes. E) Cells are joined by tight junctions. ANS: C
TOP: Concept 44.4
38) Which of the following processes of osmoregulation by the kidney is the least selective? A) salt pumping to control osmolarity B) H+ pumping to control pH C) reabsorption D) filtration
E) secretion ANS: D
TOP: Concept 44.4
39) Proper functioning of the human kidney requires considerable active transport of sodium in the kidney tubules. If these active transport mechanisms were to stop completely, how would urine production be affected? A) No urine would be produced. B) A less-than-normal volume of hypoosmotic urine would be produced. C) A greater-than-normal volume of isoosmotic urine would be produced. D) A greater-than-normal volume of hyperosmotic urine would be produced. E) A less-than-normal volume of isoosmotic urine would be produced. ANS: C
TOP: Concept 44.4
40) Which one of the following is extremely important for water conservation in mammals? A) juxtamedullary nephrons B) Bowman's capsule C) urethra D) podocytes E) ureter ANS: A
TOP: Concept 44.4
41) Which one of the following, if present in a urine sample, would likely be caused by trauma? A) amino acids B) glucose C) salts D) erythrocytes E) vitamins ANS: D
TOP: Concept 44.5
42) A toxin that specifically blocks active transport in the loop of Henle might result in which of the following? A) a decrease in the interstitial concentration of NaCl B) a decrease in the filtrate concentration ability of the kidney C) an increase in the amount of interstitial urea to maintain interstitial osmolarity D) A and C only E) A, B and C ANS: E
TOP: Concept 44.5
43) Depending on salt intake and water availability, humans can produce urine that is A) hyperosmotic to body fluids. B) hypoosmotic to body fluids. C) isoosmotic to body fluids. D) A and B are true. E) A, B, and C are true. ANS: E
TOP: Concept 44.5
44) Which structure increases the reabsorption of Na+ when stimulated by aldosterone? A) loop of Henle B) collecting duct C) Bowman's capsule
D) proximal tubule E) distal tubules ANS: E
TOP: Concept 44.5
45) What would account for increased urine production as a result of drinking alcoholic beverages? A) increased aldosterone production B) increased blood pressure C) decreased amount of antidiuretic hormone (ADH) D) increased reabsorption of water in the proximal tubule E) the osmoregulator cells of the brain increasing their activity ANS: C
TOP: Concept 44.5
46) In a laboratory experiment with three groups, one group of people drinks pure water, a second group drinks an equal amount of beer, and a third group drinks an equal amount of concentrated salt solution all during the same time period. Their urine production is monitored for several hours. At the end of the measurement period, which group will have produced the greatest volume of urine and which group the least? A) beer the most, salt solution the least B) salt solution the most, water the least C) water the most, beer the least D) beer the most, water the least E) There will be no significant difference between these groups. ANS: A
TOP: Concept 44.5
47) Which of the following activities would initiate an osmoregulatory adjustment brought about primarily through the renin-angiotensin-aldosterone system? A) sleeping B) spending several hours mowing the lawn on a hot day C) eating a bag of potato chips D) eating a pizza with olives and pepperoni E) drinking several glasses of water ANS: B
TOP: Concept 44.5
48) Hormones involved in the production of urine include all of the following except A) aldosterone. B) angiotensin. C) ADH. D) atrial natriuretic factor. E) secretin. ANS: E
TOP: Concept 44.5
49) Which statement is true about marine fishes? A) Compared to marine fishes, freshwater fishes have fewer glomeruli. B) The kidneys of marine fishes excrete little urine. C) Marine fishes lack proximal tubules. D) Marine fishes secrete uric acid to conserve water. E) Their kidneys produce filtrate at high rates. ANS: B
TOP: Concept 44.6
