Deck 42: Water and Electrolyte Balance in Animals

Question 1

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.

Answer 1

B

Question 2

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 through 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.

Answer 2

B

Question 3

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 transport additional electrolytes into the circulation of these organisms.
C)Gill lamellae take up additional electrolytes from freshwater.
D)There is an increase in Na⁺/K⁺-ATPase activity across the basolateral membrane.

Answer 3

C

Question 4

Table 42.1

Refer to Table 42.1:
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 with their osmotic gradient.
D)The rectal gland is unable to concentrate these ions.

Question 5

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 6

What is the function of the shark rectal gland?

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

Question 7

Table 42.1

The intercellular concentration of three electrolytes is compared with the concentration of these electrolytes in fluid eliminated from the shark rectal gland in Table 42.1.Based on the 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 cannot store Na⁺,K⁺,and Cl⁻.
D)The rectal gland is the only site of osmoregulation in the shark.

Question 8

Which of the following affects the osmolarity of a solution?

A)concentration of cations
B)concentration of anions
C)concentration of water
D)all of the above

Question 9

Sharks live in seawater.Their tissues 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.How is that possible?

A)Urea and trimethylamine oxide contribute to intra- and extracellular osmolarity in shark tissues.
B)Metabolic intermediates of sharks tie up intracellular chloride and potassium ions.
C)Their blood is hypotonic to their tissues.
D)They excrete large quantities of electrolytes.

Question 10

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 11

Gas exchange in insects takes place across the epithelium of the tracheae (a system of tubes).The tracheal system connects to the outside air by openings called spiracles.Muscles just inside each spiracle can control the opening to minimize water loss.What would happen if the muscles inside each spiracle were unable to function?

A)The insect would be unable to eliminate carbon dioxide.
B)The insect would increase water consumption.
C)Respiration in the insect would function normally.
D)Paralysis would result.

Question 12

Which of the following most accurately describes selective permeability?

A)Molecules below a certain molecular weight cross the membrane easily.
B)Lipid-soluble molecules pass through the membrane.
C)There must be a concentration gradient for molecules to pass through the membrane.
D)Only certain molecules can cross the cell membrane.

Question 13

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 14

Which of the following is an example of osmoregulation?

A)two solutions that are isotonic
B)the contractile vacuole of a Paramecium
C)type 2 diabetes mellitus
D)all of the above

Question 15

Hagfish (Eptatretus cirrhauts)are a jawless marine vertebrate that are isotonic with their environment and are considered to be osmoconformers.How might this interesting adaptation limit the habitat that the hagfish can tolerate?

A)Hagfish are not limited by salinity.
B)Osmoconformers do not face the same osmoregulators pressures as osmoregulators and can live in any marine environment.
C)Individual hagfish will adapt to different salinities over their lifetime and therefore can inhabit any marine environment.
D)Hagfish habitat is limited by the salinity of the environment.

Question 16

Marine vertebrates are _____ to their environment.

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

Question 17

What role do chloride cells play in osmoregulation of marine fish with bony skeletons?

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 18

Paramecia live in pond water (a hypotonic environment).They have a structural feature,a contractile vacuole,that enables them to osmoregulate.If you observed paramecia in the following solutions,at which sucrose concentration would you expect the contractile vacuole to be most active?

A)0)0 mM sucrose
B)0)05 mM saline
C)0)08 mM sucrose
D)1)0 mM saline

Question 19

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 20

Freshwater fish are hypertonic compared to their environment.To maintain homeostasis in this environment,they 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

Question 21

Figure 42.1

Figure 42.1 shows a nephron.Where does filtration take place in the nephron?

Question 22

Through studies on the 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 23

Water loss from insect 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 small surface area/volume relationship

Question 24

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 25

How does ion composition of pre-urine differ from 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 26

In flour beetles and desert locusts,how is water conserved?

A)The pre-urine formed in the Malpighian tubules is hypertonic.
B)Urine that is formed is isotonic to hemolymph,but the muscle cells surrounding spiracles of these organisms are able to significantly limit water loss due to respiration.
C)Water is transported into hindgut cells through endocytosis.
D)Sodium and chloride are actively transported out of pre-urine,and water follows,forming a hypertonic urine.

Question 27

A potassium ion gradient is set up in the 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 28

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 29

One of the waste products that accumulates during cellular functions is carbon dioxide.It is removed via the respiratory system.What is another waste product that accumulates during normal physiological functions in vertebrates?

A)ammonia
B)uric acid
C)urea
D)All of the above are examples of waste products in vertebrates.

Question 30

What is the function of the osmotic gradient found in the kidney?

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

Question 31

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

A)The kidneys require 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)None of the above are true.

Question 32

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 33

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 34

Glucose is removed in the proximal convoluted tubules.Therefore,glucose is not expected to be found in a normal urine sample.However,glucose is found in the urine of diabetics.Why is this the case?

A)More glucose can pass into the nephron because the concentration of the glucose in the blood is very high.
B)The transport of glucose from the pre-urine 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 surrounding the nephron and into the pre-urine.
D)Diabetics have active transport of glucose from the blood into the pre-urine when blood glucose levels become very high.

Question 35

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

A)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 36

If you are hiking through the desert for several days,one would pack which of the following 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 37

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 38

Your doctor takes a urine sample and finds protein in your urine.She orders one urine sample a day for one week.After analysis of the urine she does not see the protein elevation in any of the samples.Which of the following questions should she ask to determine what might have lead to this transient protein elevation?

A)"Did you eat a large meal in the last 24 hours?"
B)"Did you engage in any vigorous exercise in the last 24 hours?"
C)"Did you stay up studying last night?"
D)"Are you fasting for Ramadan?"