Ch 44
The loop of Henle dips into the renal cortex. This is an important feature of osmoregulation in terrestrial vertebrates because _____.
differential permeabilities of ascending and descending limbs of the loop of Henle are important in establishing an osmotic gradient
To maintain homeostasis, freshwater fish must ________.
excrete large quantities of water
Which process in the nephron is LEAST selective?
filtration
Excessive formation of uric acid crystals in humans leads to _____.
gout, a painful inflammatory disease that primarily affects the joints
The body fluids of an osmoconformer would be ________ with its ________ environment
isoosmotic; seawater
Ammonia is likely to be the primary nitrogenous waste in living conditions that include _____.
lots of fresh water flowing across the gills of a fish
Animals have adapted different mechanisms for excreting nitrogenous waste products. Which of the following are selective pressures that likely influence which mechanism an animal uses? I) the amount of water available in the animal's habitat II) the energy needs of the animal III) the temperature of the animal's environment
only I and II
Birds secrete uric acid as their nitrogenous waste because uric acid _____.
requires little water for nitrogenous waste disposal, thus reducing body mass
Urea is _____.
the primary nitrogenous waste product of humans
The advantage of excreting nitrogenous wastes as urea rather than as ammonia is that ________.
urea is less toxic than ammonia