Hill Ch 28: Water and Salt Physiology of Animals in Their Environments

Multiple Choice Questions

• Question 1: Marine teleosts living in seawater (800 mOsm) have an osmotic pressure of 500 mOsm.

• Question 2: Freshwater animals regulate their blood osmolarity to approximately 120 mOsm, given freshwater osmolarity of 100 mOsm.

• Question 3: Freshwater animals maintain blood osmolarity at a level that is hyposmotic to the surrounding water.

• Question 4: Freshwater animals regulate blood osmotic pressure to a level that is hyposmotic to the surrounding water.

• Question 5: Freshwater animals' osmotic regulation involves being hyperosmotic regulators.

• Question 6: Freshwater mussels, crayfish, brown trout, and frogs have varying concentrations of sodium ions in their plasma. Crayfish have the highest.

• Question 7: Freshwater animals tend to gain water and lose ions (or lose water and gain ions).

• Question 8: Damage to a crayfish's antennal gland results in loss of chemical consistency.

• Question 9: The antennal gland opens at the base of the second antenna.

• Question 10: Freshwater crayfish integument is less permeable to water and sodium, about 10%, than the integument of marine decapods of similar size.

• Question 11: Fresh water animals' integuments have low permeability to maintain water and ion balance without expending much energy.

• Question 12: Gills in freshwater crayfish provide an advantage for oxygen intake but a disadvantage for water intake. The advantage will be oxygen intake and the disadvantage will be for water uptake.

• Question 13: Crayfish have the lowest osmotic U/P ratio.

• Question 14: Mitochondria is the most important organelle in moving sodium and chloride in freshwater animals.

• Question 15: Sodium intake from environment in frogs will continue if sodium concentration in the environment increases, and will cease if it decreases. This intake happens via primary active transport.

• Question 16: Similar to question 15, if chloride concentration in the environment increases, chloride intake from the environment will continue to occur by active transport.

• Question 17: The epithelial cells of gills in freshwater fish become increasingly negative because chloride ions are negative, due to Cl chloride active transport.

• Question 18: The epithelial cells of gills in freshwater fish become increasingly positive due to sodium ions being positive, due to sodium active transport.

• Question 19: Bicarbonate pumped from gills in freshwater fish into the water comes from carbon dioxide.

• Question 20: Sodium movement in frogs involves energy-requiring mechanisms across the skin, and its movement regulates acid–base levels.

• Question 21: Chloride movement in frogs does not involve proton movement.

• Question 22: The major site of sodium exchange in adult freshwater fish is the gills.

• Question 23: The major site of chloride exchange in early freshwater fish larvae is the skin.

• Question 24: Ion exchange in adult freshwater teleosts occurs in gill lamellae.

• Question 25: The most common proteins found in the gills of freshwater teleosts are Na+-K+-ATPases and Na+/Cl¯/K+ cotransporters.

• Question 26: Chloride cells are not responsible for producing carbon dioxide.

• Question 27: Inhibiting mitochondria in the gills of freshwater fish would result in chloride cells ceasing to function.

• Question 28: Increasing calcium chelators (like BAPTA) in the freshwater fish environment will increase chloride cells.

• Question 29: There are approximately 100,000,000 Na⁺–K⁺-ATPase molecules in each MRC.

• Question 30: Increased Cl¯/HCO3¯ countertransport protein expression in fish MRCs indicates a basic environment.

• Question 31: If the freshwater fish environment is highly basic, Cl¯/HCO3- protein expression will increase dramatically.

• Question 32: Sodium in freshwater fish is lost via excretion (2-3 µmoles per day) in urine and diffusion (240 µmoles per day) across the body.

• Question 33: Freshwater fish lose approximately 240 µmoles of sodium per day.

• Question 34: Squid's inner body fluid is isosmotic to seawater.

• Question 35: If an octopus has an osmolarity of 300 mOsm, the environment it lives in must have an osmolarity of 300 mOsm.

• Question 36: If sodium concentration in a squid's body fluid is 456 mmol/kg of H₂O, the intracellular sodium concentration is 5 mmol/kg of H₂O.

• Question 37: If the potassium concentration in a squid's body fluid is 22 mmol/kg of H₂O, the intracellular potassium concentration is 12 mmol/kg of H₂O.

• Question 38: Blood osmotic pressure in marine teleosts is lower than the environmental osmotic pressure by approximately 600 mOsm.

• Question 39: Sodium moves faster than chloride across marine gills due to the overall negative charge inside the gill epithelium.

• Question 40: Chloride channels in the mitochondria-rich cells of marine teleosts are located on apical membrane(s).

• Question 41: Chloride enters the cell in the mitochondria-rich cells of marine teleosts through the apical membrane by simple diffusion and exits via the basolateral membrane through secondary active transport.

• Question 42: Marine echinoderms are not hyposmotic regulators.

• Question 43: Stenohaline species can only survive under specific salinity ranges.

• Question 44: Anadromous animals leave saltwater to breed in freshwater environments.

• Question 45: Catadromous animals leave freshwater and breed in saltwater environments.

• Question 46: Immunocytochemistry would show an increased aquaporin expression and increased NKCC expression in the intestinal epithelia, and decreased NKCC expression in the gill lamellae if a freshwater animal is transferred to saltwater for 60 days.

• Question 47: The blue crab is a hyperosmotic regulator.

• Question 48: Brine shrimp is the best osmotic regulator according to the graph.

• Question 49: Brine shrimp is the species that best mirrors the profile of a Pacific salmon if taking into account the numerical scales and shape of the graphs, and this is closely depicted by the graph line.

• Question 50: Xeric animals can survive in dry, water-poor environments.

• Question 51: Proteins are the substances that produce nitrogen waste when catabolized.

• Question 52: House wrens have the highest weight-specific total rate of evaporative water loss.

• Question 53: The line "I" represents total evaporative water loss.

• Question 54: The line "II" represents metabolic water production in animals.

• Question 55: Antidiuretic hormone (ADH) is released from the neurohypophysis in terrestrial amphibians.

• Question 56: Evaporation contributes most to total water loss in the presented animal.

• Question 57: Preformed water in food is not a consistent value because humidity affects the water content in the food.

• Question 58: The animal is out of water balance at low humidity.

• Question 59: Factors determining rate of passive exchange of water and ions include osmotic and ionic gradients between blood and surrounding water, the permeability of the covering to water and ions, and the area across which the exchanges happen.

• Question 60: Permeability of freshwater animal integuments is relatively low to reduce passive exchange rates for water and ions and save energy for maintaining normal blood composition.

• Question 61: Gills have a structure of secondary lamellae that vastly expands the surface area for oxygen diffusion and ion transport.

• Question 62: Immunocytochemistry is used by labeling antibodies with fluors to identify the locations of ion transport proteins in gill filaments; when a laser excites the fluors, images can locate proteins like Na⁺–K⁺-ATPase and cotransporter NKCC-1.

• Question 63: Increasing environmental bicarbonate (alkalosis) results in a higher number of mitochondria-rich cells (MRCs) in fish gills.

• Question 64: Freshwater fish produce dilute urine to save energy by taking up ions effectively from more concentrated substances in the water.

• Question 65: To replenish water loss via diffusion and excretion, teleosts drink hyperosmotic seawater; water moves into the blood through osmosis due to ionic gradient created by the active transport of sodium and chloride.

• Question 66: Rate of water loss correlates with oxygen consumption due to respiratory evaporative water loss, depending on the animal's O² consumption rate and how much water is lost per O2 consumed.

• Question 67: Amphibians compensate for water loss by using urea for nitrogenous waste to require less water and by absorbing substantial amounts of water across their skin, as well as moderating water loss through behavioral adaptation.

• Question 68: The species that can survive in a wide range of ambient salinity are called euryhaline.

• Question 69: Animals ascending rivers from the ocean to breed are anadromous.

• Question 70: The graph shows evaporative water loss in relationship to the body weight of different animals.

• Question 71: The line in the graph showing the relationship between evaporative water loss and body weight shows that water permeability decreases in response to increasing the concentration of aquaporins in the pelvic membrane of a frog.