Ch 44 BioOrg
Juxtamedullary nephrons can concentrate salt effectively in the renal medulla because of their long
) loops of Henle.
The typical osmolarity of human blood is
300 mosm/L.
(Picture 8) Which of the following is excreted readily by aquatic animals because of its high solubility in the respiratory medium?
A
ADH and RAAS work together in maintaining osmoregulatory homeostasis through which of the following ways?
ADH regulates the osmolarity of the blood by altering renal reabsorption of water, and RAAS maintains the osmolarity of the blood by stimulating Na+ reabsorption.
(Picture 8)Which of the following is synthesized by mammals, most amphibians, sharks, and some bony fishes, and has lower toxicity than its nitrogenous substrate?
B
(Picture 8) Which of the following is excreted as a paste by land snails, insects, birds, and many reptiles, because of its solubility and toxicity properties?
C
The osmoregulatory/excretory system of an insect is based on the operation of
Malpighian tubules.
African lungfish, which are often found in small stagnant pools of fresh water, produce urea as a nitrogenous waste. What is the advantage of this adaptation?
Small stagnant pools do not provide enough water to dilute the toxic ammonia.
Which of the following animals generally has the lowest volume of urine production?
a marine bony fish
Natural selection should favor the highest proportion of juxtamedullary nephrons in which of the following species?
a mouse species living in a desert
The osmolarity of human urine
can be four times as great as normal osmolarity of human plasma.
Antidiuretic hormone (ADH) functions at the cellular level by
causing an increase in the number of aquaporin molecules of collecting duct cells.
The high osmolarity of the renal medulla is maintained by all of the following except
diffusion of salt from the descending limb of the loop of Henle.
Choose a pair that correctly associates the mechanism for osmoregulation or nitrogen removal with the appropriate animal.
direct cellular exchangemarine invertebrate
Birds that live in marine environments and thus lack access to fresh drinking water
drink seawater and secrete excess ions mainly through their nasal salt glands.
Trauma to the human kidney could result in a urinary filtrate containing an abnormally high level of
erythrocytes.
Which process in the nephron is least selective?
filtration
Low selectivity of solute movement is a characteristic of
filtration from the glomerular capillaries.
Excretory structures known as protonephridia are present in
flatworms.
Many marine and freshwater bony fish achieve osmoregulation via
gain of water through food.
Excessive formation of uric acid crystals in humans leads to
gout, a painful inflammatory disease that primarily affects the joints.
In humans, the transport epithelial cells in the ascending loop of Henle
have plasma membranes of low permeability to water.
Human urine is usually more acidic than most other body fluids because
hydrogen ions are actively moved into the filtrate.
If ATP production in a human kidney was suddenly halted, urine production would
increase, and the urine would be isoosmotic compared to plasma.
After drinking alcoholic beverages, increased urine excretion is the result of
inhibited secretion of antidiuretic hormone (ADH).
Which of the following pairs of organisms excrete nitrogenous wastes in the form of uric acid?
insects and birds
Excretory organs known as Malpighian tubules are present in
insects.
Ammonia
is soluble in water.
Compared to the seawater around them, most marine invertebrates are
isoosmotic.
The body fluids of an osmoconformer would be ________ with its ________ environment.
isoosmotic; saltwater
A primary reason that the kidneys have one of the highest metabolic rates of all body organs is that
it operates an extensive set of active-transport ion pumps.
A necropsy (postmortem analysis) of a marine sea star that died after it was mistakenly placed in fresh water would likely show that it died because
it was so hyperosmotic to the fresh water that it could not osmoregulate.
Compared to wetland mammals, water conservation in mammals of arid regions is enhanced by having more
juxtamedullary nephrons.
An excretory system that is partly based on the filtration of fluid under high hydrostatic pressure is the
kidneys of vertebrates.
Urea is produced in the
liver from NH3 and CO2.
The necropsy (postmortem analysis) of a freshwater fish that died after being placed accidentally in saltwater would likely show that
loss of water by osmosis from cells in vital organs resulted in cell death and organ failure.
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.
Processing of filtrate in the proximal and distal tubules
maintains homeostasis of pH in body fluids.
Freshwater flatworms form a urine that is typically
of low solute concentration and of high volume, matching their normal fluid uptake.
The filtrate in the proximal convoluted tubule of the human does not normally include
plasma proteins.
In animals, nitrogenous wastes are produced mostly from the catabolism of
proteins and nucleic acids.
The osmoregulatory/excretory system of a freshwater flatworm is based on the operation of
protonephridia.
Unlike an earthworm's metanephridia, a mammalian nephron
receives filtrate from blood instead of coelomic fluid.
After blood flow is artificially reduced at one kidney, you would expect that kidney to secrete more of the hormone known as
renin.
Materials are returned to the blood from the filtrate by which of the following processes?
selective reabsorption
Osmoregulatory adjustment via the renin-angiotensin-aldosterone system can be triggered by
severe sweating on a hot day.
A person with alkalosis will likely excrete urine that has abnormally high levels of
sodium ions.
Unlike most bony fishes, sharks maintain body fluids that are isoosmotic to seawater, so they are considered by many to be osmoconformers. Nonetheless, these sharks osmoregulate at least partially by
tolerating high urea concentrations that balance internal salt concentrations to seawater osmolarity.
The advantage of excreting nitrogenous wastes as urea rather than as ammonia is that
urea is less toxic than ammonia.
Which nitrogenous waste has the greatest number of nitrogen atoms?
uric acid
Osmoconforming sharks take in water, as needed,
via osmosis, as their body cells are slightly hyperosmotic to seawater.
Which nitrogenous waste requires hardly any water for its excretion? A) amino acids
uric acid
The nitrogenous waste that requires the most energy to produce is
uric acid.
In a laboratory experiment with three groups of students, one group 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. Which groups are expected to have the greatest and least amounts of urine, respectively?
Beer drinkers have the most; salt solution drinkers have the least.
Among vertebrate animals, urea
is made in the liver by combining two ammonia molecules with one carbon dioxide.
The transfer of fluid from the glomerulus to Bowman's capsule
is mainly a consequence of blood pressure in the capillaries of the glomerulus.
Among the following choices, the most concentrated urine is excreted by
kangaroo rats.
Organisms categorized as osmoconformers are most likely
marine.
The osmoregulatory/excretory system of an earthworm is based on the operation of
metanephridia.
Birds secrete uric acid as their nitrogenous waste because uric acid
requires little water for nitrogenous waste disposal, thus reducing body mass.
The fluid with the highest osmolarity is
seawater in a tidal pool.
The osmoregulatory process called secretion refers to the
selective elimination of excess ions and toxins from body fluids
Increased ADH secretion is likely after
sweating-induced dehydration increases plasma osmolarity.
The filtrate in the renal pelvis enters directly from
the collecting duct.
When stimulated by aldosterone, the reabsorption of Na+ is increased along
the distal tubule.
Urea is
the primary nitrogenous waste product of humans.
Within a normally functioning kidney, blood can be found in
the vasa recta.
The primary nitrogenous waste excreted by birds is
uric acid.
A human who has no access to fresh water but is forced to drink seawater instead
will excrete more water molecules than taken in, because of the high load of ion ingestion.