Deck 40: Water and Electrolyte Balance in Animals

Question 1

To maintain homeostasis freshwater fish must ________.

A) excrete large quantities of electrolytes
B) consume large quantities of water
C) excrete large quantities of water
D) take in electrolytes through simple diffusion

Answer 1

C

Question 2

One of the waste products that accumulates during cellular functions is carbon dioxide. It is removed via the respiratory system. What other waste product(s) accumulate during normal physiological functions in vertebrates?
I) ammonia
II) uric acid
III) urea

A) only I and III
B) only II and III
C) only I and II
D) I, II, and III

Answer 2

D

Question 3

Organisms categorized as osmoconformers are most likely ________.

A) found in freshwater lakes and streams
B) marine
C) amphibious
D) found in arid terrestrial environments
E) found in terrestrial environments with adequate moisture

Answer 3

B

Question 4

Among vertebrate animals, urea is ________.

A) made in the kidneys and immediately excreted
B) added to the air in the lungs to be exhaled, along with carbon dioxide
C) made in the liver by combining ammonia molecules or amino groups.
D) made in the pancreas and added to the intestinal contents, along with bile salts, for excretion
E) rarely the nitrogenous waste

Question 5

A necropsy (postmortem analysis) of a marine sea star that died after it was mistakenly placed in freshwater would likely show that it died because ________.

A) it was stressed and needed more time to acclimate to the new conditions
B) it was so hypertonic to the freshwater that it could not osmoregulate
C) the sea star's kidneys could not handle the change in ionic content presented by the freshwater
D) its contractile vacuoles ruptured
E) its cells dehydrated and lost the ability to metabolize

Question 6

When a cell is in equilibrium with its environment, which of the following occurs for substances that can diffuse through the cell?

A) There is random movement of substances into and out of the cell.
B) There is directed movement of substances into and out of the cell.
C) There is no movement of substances into and out of the cell.
D) All movement of molecules is directed by active transport.

Question 7

Ammonia is likely to be the primary nitrogenous waste in living conditions that include ________.

A) lots of freshwater flowing across the gills of a fish
B) lots of seawater, such as a bird living in a marine environment
C) lots of seawater, such as a marine mammal (for example, a polar bear)
D) a terrestrial environment, such as that supporting crickets
E) a moist system of burrows, such as those of naked mole rats

Question 8

Urea 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

Question 9

Compared to the seawater around them, most marine invertebrates are ________.

A) hyperosmotic
B) hypoosmotic
C) isoosmotic
D) hyperosmotic and isoosmotic
E) hypoosmotic and isoosmotic

Question 10

The body fluids of an osmoconformer would be ________ with its ________ environment

A) hyperosmotic; freshwater
B) isoosmotic; freshwater
C) hyperosmotic; saltwater
D) isoosmotic; saltwater
E) hypoosmotic; saltwater

Question 11

The advantage of excreting nitrogenous 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

Question 12

A human who has no access to freshwater but is forced to drink seawater instead will ________.

A) thrive under such conditions, as long as he has lived at the ocean most of his life
B) excrete more water molecules than taken in, because of the high load of ion ingestion
C) develop structural changes in the kidneys to accommodate the salt overload
D) find that drinking saltwater satiates his thirst
E) risk becoming overhydrated within 12 hours

Question 13

Which of the following mechanisms contributes to osmoregulation in both marine and freshwater bony fish?

A) gain of water through the gills via osmosis
B) gain of salt through the gills via active transport
C) loss of salt through the gills via diffusion
D) excretion of hyperosmotic urine
E) gain of water through food

Question 14

Marine vertebrates are ________ to their environment.

A) isotonic
B) hypotonic
C) hypertonic
D) osmotonic

Question 15

Both marine bony fishes and terrestrial animals lose water to the environment. However, a difference is that the bony fishes lose water by ________, while the terrestrial animals lose it by ________.

A) osmosis; evaporation
B) active transport; osmosis
C) osmosis; simple diffusion
D) evaporation; active transport

Question 16

The force driving simple diffusion is ________, while the energy source for active transport is ________.

A) the concentration gradient; ADP
B) the concentration gradient; ATP
C) transmembrane pumps; electron transport
D) phosphorylated protein carriers; ATP

Question 17

Which of the following most accurately describes selective permeability?

A) An input of energy is required for transport.
B) Lipid-soluble molecules pass through a membrane.
C) There must be a concentration gradient for molecules to pass through a membrane.
D) Only certain molecules can cross a cell membrane.

Question 18

Ammonia ________.

A) is soluble in water
B) can be stored in the body as a precipitate
C) has low toxicity relative to urea
D) is metabolically more expensive to synthesize than urea
E) is the major nitrogenous waste excreted by insects

Question 19

The fluid with the highest osmolarity is ________.

A) distilled water
B) plasma in birds
C) plasma in mammals
D) seawater in a tidal pool
E) estuarine water

Question 20

The nitrogenous waste that requires the most energy to produce is ________.

A) ammonia
B) ammonium
C) urea
D) uric acid

Question 21

Tissues of sharks are isotonic to seawater, but their concentrations of sodium ions, potassium ions, and chloride ions in cells and extracellular fluids are similar to those of freshwater fishes. What can you infer about the movement of sodium and chloride in these animals?

A) To maintain homeostasis of sodium and chloride levels, the shark must take up additional sodium and chloride from seawater.
B) Sodium and chloride will diffuse into shark gills from seawater down their concentration gradient.
C) Sharks conserve sodium and chloride, limiting excretion.
D) Sodium and chloride must be eliminated through the gills.

Question 22

Osmoregulation in the Shark
The interstitial fluid concentration of three electrolytes is compared with the concentration of these electrolytes in fluid eliminated from the shark rectal gland as indicated in the accompanying table. Based on these data, which of the following is a likely function of the rectal gland?

A) The rectal gland eliminates metabolic waste.
B) The rectal gland is able to concentrate Na+, K+, and Cl−.
C) The rectal gland stores only anions.
D) The rectal gland is the only site of osmoregulation in the shark.

Question 23

Salmon and sea bass are useful for studies of the role of the gills in osmoregulation in fishes because ________.

A) they live in freshwater and in seawater at different life history stages
B) they are unique fishes that osmoconform to seawater
C) they excrete extremely high levels of salts in freshwater environments
D) they both feed on marine invertebrates, increasing their salt intake

Question 24

Which nitrogenous waste requires hardly any water for its excretion?

A) amino acids
B) urea
C) uric acid
D) ammonia
E) nitrogen gas

Question 25

Through studies of insect Malpighian tubules, researchers found that K+ accumulated on the inner face of the tubule, against its concentration gradient. What can you infer about the mechanism of transport?

A) Potassium transport is a passive process.
B) Movement of potassium into the lumen of the Malpighian tubules is an energy-requiring process.
C) Potassium moves out of the tubules at a faster rate than it moves into the lumen of the tubules.
D) Sodium ions will follow potassium ions.

Question 26

What role does Na+/K+-ATPase play in salt excretion by the shark rectal gland?

A) Na+/K+-ATPase pumps sodium out and potassium into cells across the apical membrane.
B) Na+/K+-ATPase pumps sodium in and potassium out of cells across the apical membrane.
C) Na+/K+-ATPase pumps sodium out and potassium into cells across the basolateral membrane.
D) Na+/K+-ATPase pumps sodium into and potassium out of cells across the basolateral membrane.

Question 27

Osmoregulation in the Shark
Refer to the accompanying table. Because the shark rectal gland functions only when ATP molecules are present, what can you infer about the movement of Na+, K+, and Cl−?

A) Movement of these ions from circulation into the rectal gland is an active process.
B) Movement of these ions takes place from a region of higher concentration to a region of lower concentration.
C) These ions move into the rectal gland down their concentration gradient.
D) The rectal gland is unable to concentrate these ions.

Question 28

Water loss from a terrestrial insect's surface is minimal due to which of the following structures?

A) chitin and the cuticle
B) tracheae and spiracles
C) a proteinaceous epidermis
D) a long alimentary canal

Question 29

Salmon eggs hatch in freshwater. The fish then migrate to the ocean (a hypertonic solution) and, after several years of feeding and growing, return to freshwater to breed. How can these organisms make the transition from freshwater to ocean water and back to freshwater?

A) The rectal gland functions in the ocean water, and chloride cells function in freshwater.
B) Different gill cells are involved in osmoregulation in freshwater than in salt water.
C) Salmon in freshwater excrete dilute urine, and salmon in salt water secrete concentrated urine.
D) Their metabolism changes in salt water to degrade electrolytes.

Question 30

African lungfish, which are often found in small, stagnant pools of freshwater, produce urea as a nitrogenous waste. What is the advantage of this adaptation?

A) Urea takes less energy to synthesize than ammonia.
B) Small, stagnant pools do not provide enough water to dilute the toxic ammonia.
C) The highly toxic urea makes the pool uninhabitable to potential competitors.
D) Urea forms an insoluble precipitate.
E) Urea makes lungfish tissue hypoosmotic to the pool.

Question 31

Freshwater fish reside in hypotonic environments. They do not drink water, and they excrete large volumes of hypotonic urine in an effort to osmoregulate. How do they obtain an adequate supply of electrolytes?

A) The rectal gland is specialized to produce the dilute (hypotonic) urine and conserve ions.
B) Chloride cells in the gut transport additional electrolytes into the circulation of these organisms.
C) Chloride cells on the gill filaments take up additional electrolytes from freshwater.
D) There is an increase in Na+/K+-ATPase activity across the basolateral membrane.

Question 32

How do spiracles contribute to the minimization of water loss in insects?

A) Spiracles contribute to water recovery from the hindgut.
B) The spiracles control the opening of the Malpighian tubules.
C) The opening of spiracles allows for water uptake during a period of rain.
D) The closure of spiracles prevents evaporative water loss from the tracheae.

Question 33

Terrestrial organisms lose water through evaporation. In what ecosystem might an entomologist find a good study organism to examine the prevention of water loss?

A) wet rain forest
B) desert
C) prairie
D) chaparral

Question 34

Insect Malpighian tubules form pre-urine, which is further processed by which of the following anatomical structures?

A) hindgut
B) hemolymph
C) rectal gland
D) spiracles

Question 35

What role do chloride cells play in osmoregulation of marine bony fishes?

A) They actively transport chloride into the gills.
B) They mediate the movement of salt from seawater through their gills.
C) They are involved in excretion of excess salt.
D) They actively transport salt across the basolateral membrane of the rectal gland.

Question 36

The Na+/Cl−/K+ cotransporter in the epithelial cells of the gills of bony fishes is found ________.

A) on the basolateral membrane of freshwater and marine fishes
B) on the basolateral membrane of marine fishes and the apical membrane of freshwater fishes
C) on the basolateral membrane of freshwater fishes and the apical membrane of marine fishes
D) on the apical membrane of freshwater and marine fishes
E) only in larval fish

Question 37

The necropsy (postmortem analysis) of a freshwater fish that died after being placed accidentally in saltwater would likely show that ________.

A) loss of water by osmosis from cells in vital organs resulted in cell death and organ failure
B) high amounts of salt had diffused into the fish's cells, causing them to swell and lyse
C) the kidneys were not able to keep up with the water removal necessary in this hyperosmotic environment, creating an irrevocable loss of homeostasis
D) the gills became encrusted with salt, resulting in inadequate gas exchange and a resulting asphyxiation
E) brain cells lysed as a result of increased osmotic pressure in this hyperosmotic environment, leading to death by loss of autonomic function

Question 38

Birds secrete uric acid as their nitrogenous waste because uric acid ________.

A) is readily soluble in water, permitting its release in dilute urine
B) is metabolically intermediate to synthesize than other excretory products, balancing metabolic costs and water loss
C) requires little water for nitrogenous waste disposal, thus conserving water and reducing body mass
D) is produced from their low-protein diet

Question 39

In animals, nitrogenous wastes are produced mostly from the catabolism of ________.

A) starch and cellulose
B) triglycerides and steroids
C) proteins and nucleic acids
D) phospholipids and glycolipids
E) fatty acids and glycerol

Question 40

The shark rectal gland ________.

A) is involved in osmoregulation
B) is responsible for excretion of undigested residue
C) secretes a hypotonic solution
D) concentrates electrolytes necessary for homeostasis in a hypertonic environment

Question 41

If you are hiking through the desert for several days, which of the following should you drink to ensure proper hydration?

A) a drink with a combination of water and electrolytes
B) caffeinated beverages
C) bottled water kept at room temperature
D) bottled water that had been frozen to ensure that it would be as cold as possible

Question 42

The accompanying figure shows a nephron. Filtration takes place in the structure labeled ________.

A) a
B) b
C) c
D) d

Question 43

In a grasshopper, how does ion composition of pre-urine compare to hemolymph?

A) Pre-urine is significantly higher in osmolarity (especially with respect to Na+ and K+).
B) Hemolymph is higher in osmolarity, conserving its Cl−.
C) Pre-urine is similar to hemolymph in ion composition.
D) The protein pumps and channels of the Malpighian tubules concentrate Cl− in the pre-urine.

Question 44

Which of the following is a function of antidiuretic hormone (ADH)?

A) ADH decreases the reabsorption of urea, creating a higher urea content in the urine.
B) ADH triggers the insertion of water channels called aquaporins, thereby reducing the amount of water reabsorbed by the collecting duct.
C) ADH improves the reabsorption of glucose by the proximal convoluted tubule.
D) ADH triggers the insertion of water channels called aquaporins, thereby increasing the amount of water reabsorbed by the collecting duct.
E) ADH alters the ion reabsorption by the loop of Henle.

Question 45

The filtrate formed in the renal corpuscle is analogous to the ________ formed in Malpighian tubules.

A) hemolymph
B) pre-urine
C) uric acid
D) hypertonic solution

Question 46

Which structure in the mammalian kidney is responsible for maintaining the osmotic gradient in medulla of the kidney?

A) renal corpuscle
B) proximal tubule
C) loop of Henle
D) distal tubule
E) collecting duct

Question 47

Materials are returned to the blood from the filtrate by which of the following processes?

A) filtration
B) ultrafiltration
C) selective reabsorption
D) secretion
E) excretion

Question 48

Excretory organs known as Malpighian tubules are present in ________.

A) earthworms
B) flatworms
C) insects
D) jellyfish
E) sea stars

Question 49

The osmoregulatory/excretory system of an insect is based on the operation of ________.

A) protonephridia
B) metanephridia
C) Malpighian tubules
D) nephrons
E) ananephredia

Question 50

Which of the following pairs of organisms excrete nitrogenous wastes in the form of uric acid?

A) mice and birds
B) insects and birds
C) lions and horses
D) humans and frogs
E) fish and turtles

Question 51

Non-avian reptiles can produce hyperosmotic urine using which structure?

A) salt glands similar to birds
B) the rectum where uric acid is produced
C) water-reabsorbing cloaca
D) water-reabsorbing ureters
E) highly developed kidneys

Question 52

The loop of Henle dips into the renal cortex. This is an important feature of osmoregulation in terrestrial vertebrates because ________.

A) absorptive processes taking place in the loop of Henle are hormonally regulated
B) differential permeabilities of ascending and descending limbs of the loop of Henle are important in establishing an osmotic gradient
C) the loop of Henle plays an important role in detoxification
D) additional filtration takes place along the loop of Henle

Question 53

A potassium ion gradient is set up in insect Malpighian tubules through an active transport process. As a result, potassium concentration is higher in the lumen of the tubules than in hemolymph. How would the potassium gradient affect water movement?

A) Water would be forced out of the lumen of the Malpighian tubules through an osmotic gradient.
B) The potassium gradient would have no effect on water movement.
C) There would be a net movement of water into the lumen of the tubules.
D) Water would be conserved, forming a hypertonic solution in the Malpighian tubules.

Question 54

Why are the renal artery and vein critical to the process of osmoregulation in mammals?

A) The kidneys require a constant and abnormally high oxygen supply to function.
B) The renal artery delivers blood with nitrogenous waste to the kidney, and the renal vein brings blood with less nitrogenous wastes away from the kidneys.
C) The kidneys require higher-than-normal levels of hormones.
D) The renal artery and vein are the main pathways regulating how much is produced by the kidneys.

Question 55

For filtration to take place through the fenestrated capillaries of the renal corpuscle, ________.

A) the concentration of ions must be greater in the capillaries (the glomerulus) than in the renal tubule
B) there must be a greater pressure inside the glomerulus than in the renal tubules
C) there must be a larger concentration of proteins in the renal tubule than in the glomerulus
D) there must be more than one capillary bed in the renal corpuscle

Question 56

Reabsorption of water in the hindgut of insects is controlled by which of the following?

A) osmotic gradients created by ion pumps
B) selective absorptive processes that take place in the Malpighian tubules
C) ion concentration of hemolymph
D) osmoregulators in the rectal gland

Question 57

Birds that live in marine environments, and thus lack access to fresh drinking water, ________.

A) osmoregulate without using a transport epithelium for this purpose
B) drink seawater and secrete excess ions through their kidneys only
C) drink seawater and secrete excess ions mainly through their nasal salt glands
D) have plasma that is isoosmotic to ocean water
E) obtain water by eating only osmoregulating prey

Question 58

What is the function of the osmotic gradient found in the kidney? The osmotic gradient allows for ________.

A) electrolytes to move from low to high concentrations in the absence of ATP
B) the precise control of the retention of water and electrolytes
C) the loop of Henle to deliver water to the renal vein
D) the filtration of large cells at the glomerulus

Question 59

The products of filtration in the renal corpuscle enter the renal tubule through which of the following structures?

A) the proximal convoluted tubule
B) the loop of Henle
C) the collecting duct
D) Bowman's capsule

Question 60

Normal urine contains very little glucose. Diabetics have elevated glucose levels in their blood and urine. Which statement best explains the presence of glucose in the urine of diabetics?

A) The loop of Henle fails to reabsorb the glucose in diabetics.
B) The transport of glucose from the pre-urine within the proximal tubule back to the blood cannot occur at a rate fast enough to remove all of the glucose from the urine.
C) Glucose is passing from the blood in the vasa recta into the nephron and entering the pre-urine.
D) Diabetics have active transport of glucose from the blood into the pre-urine when blood glucose levels become very high.