the body fluids of an osmoconformer would be ( ) with its ( ) environment

isoosmotic; saltwater

which feature of osmoregulation is found in both marine and freshwater bony fish?

gain of water through food

unlike most bony fishes, sharks maintain body fluids that are isoomsotic to sea water. They are therefore considered by many to be osmoconformers because of the unusual way they maintain homeostasis. They osmoregulate by

tolerating high urea concentrations that balance internal salt concentrations to sea water osmolarity

a freshwater fish was accidentally placed in salt water. after several minutes in this aline water, it died. what is the most logical explanation for its death?

loss of water by osmosis in cells in vital organs resulting in cell death and eventually organ failure

where and from what compound(s) is urea produced?

liver from NH3 (ammonia) and CO2

which of the following is true of urea? it is

the primary nitrogenous waste product of humans

which of the following is true of ammonia?

it is soluble in water

the advantage of excreting wastes as urea rather than as ammonia is that

urea is less toxic than ammonia

birds secrete uric acid as their nitrogenous waste because uric acid

requires little water for nitrogenous waste disposal which is conducive to the function of flight in terms of weight

which of the following nitrogenous wastes requires hardly any water for its excretion?

uric acid

in animals, nitrogenous wastes are produced mostly from the catabolism of

proteins and nucleic acids

the most concentrated urine is excreted by

kangaroo rats

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

selective reabsorption

which group possess excretory structures known as protonephridia

flatworms

which group possess excretory organs known as malpighian tubules

insects

which of the following excretory systems is partly based on the filtration of fluid under high hydrostatic pressure

kidneys of vertebrates

which of the following would contain blood in a normally functioning nephron

vasa recta

which structure descends deep into the renal medulla only in juxtamedullary nephrons

loop of henle

proper functioning of the human kidney requires considerable active transport of sodium in the kidney tubules. if these active transport mechanisms were to stop completely how would urine production be affected?

a greater than normal volume of of isoosmotic urine would be produced

which one of the following is extremely important for water conservation in mammals?

juxtamedullary nephrons

what is unique about transport epithelial cells in the ascending loop of Henle in humans?

their membranes are impermeable to water

what is the typical osmolarity of human blood?

300 mosm/L

which structure increases the reabsorption of Na+ when stimulated by aldosterone?

distal tubules

what would account for increased urine production as a result of drinking alcoholic beverages

inhibition of antidiuretic hormone secretion (ADH)

which one of the following , if present in a urine sample, would likely be caused by trauma?

erythrocytes

how does ADH function at the cellular level?

it causes an increase in the number of aquaporin molecules of the collecting duct cells

which of the following activities would initiate an osmoregulatory adjustment brought about primarily through the renin-angiotensin-aldosterone system?

spending several hours mowing the lawn on a hot day

which process in the nephron is least selective?

filtration

how do ADH and RAAS work together in maintaining osmoregulatory homeostasis?

ADH monitors appropriate osmolarity by reabsorption of water, and RAAS maintains osmolarity by sitmulating Na+ reasorption

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