Term
| Differentiate among hypotonic, isotonic and hypertonic. Why can one not simply say that solution X is hypertonic? |
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Definition
hypotonic= lower concentration in animals than in water
isotonic= same concentrations of solutes in animals and in water
hypertonic= greater concentrations in animals than in water.
it must be compared to another solution |
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Term
| Explain why marine fish and freshwater fish both have osmoregulation problems. |
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Definition
they both have different osmolarity than their surrounding water in their environments.
freshwater= keep in salt and water out
marine= water in and salt out. |
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Term
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Definition
a compound that dissociates into ions when dissolved in water.
Na Cl K Ca together |
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Term
| How do saltwater fish, freshwater fish and terrestrial animals gain and lose water? Electrolytes? |
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Definition
saltwater= lose water by osmosis through gills. gain water by drinking alot electrolytes(in the water they drink )
freshwater= no water loss problem
gain water through osmosis
terrestrial= loose water through peeing and breathing. gain water through drinking. |
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Term
Sharks excrete salt via the rectal gland, but they don’t have ion channels that export either sodium or chloride. How do
they do it? |
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Definition
| the Na and Ca diffuse through spaces between the cells. and flow along electrochemical gradients. |
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Term
| Where else is the shark-rectal-gland sort of system found? Why do those organisms have them? |
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Definition
animals that drink saltwater=glands in nostrils
teleosts=in their gills
mammals= in their kidneys.
they have them because they need to get rid of excess salt because of behaviors of the individual animals. |
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Term
Why do some organisms excrete ammonia, whereas other excrete urea or uric acid? Why do organisms have to excrete
these compounds at all? |
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Definition
ammonia can be flushed out with large amounts of water and it is used by fish and other aquatic vertebrates.
Urea is made from ammonia by sharks and mammals.
Uric acid is the least toxic derivative of ammonia and it is generated by birds, reptiles, insects, and spiders. for an animal to be able to excrete ammonia they must be in an aquatic environment because it uses up a lot of water.
they are all waster products that are toxic to the organism if not contained and excreted. |
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Term
What is a podocyte? What does it do? In what organisms are they present, especially with respect to the previous
question? |
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Definition
| podoctye= a vessel in metanephridia. they filter the water and waste. the amino acids, sugars, and ions are then reabsorbed along the tubule. waste is then excreted. |
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Term
Why is the excretory process a long way from finished after the podocyte step? How is that problem rectified in
earthworms? |
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Definition
it filters all of the stuff out but doesn't put anything back in.
the nutrients get actively transported back in in earthworms. |
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Term
What happens in insects instead of the podocyte step? How is the end result the same? How is any water balance or
electrolyte imbalance rectified, if necessary? |
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Definition
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Term
| Describe the organization of the mammalian excretory system, including organs and organ components. |
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Definition
| excretion starts in the renal corpuscle. the blood pressure forces liquid and solutes to be filtered out of the blood though podocytes. into the glomerulus. way more is removed then needed. this forms the preurine. most of the solutes are then reabsorbed in the proximal tubule which has microvilli. additional water and electrolyte resorption occurs in the loops of the Henle. ions and water diffuse in and out based on the electrochemical gradient. then water is regulated at the distal tubule and the collecting duct. |
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Term
Where do most of the molecules lost during filtration get resorbed? Given your answer, what is the point of the loops of
Henle? |
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Definition
| the point is to facilitate the resorption of water and electrolytes. |
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Term
| Where in the kidney does water and electrolyte regulation occur? |
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Definition
the distal tubule and the collecting duct.
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Term
| What is osmolarity? How does it differ from molarity? From tonicity? |
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Definition
Osmolarity= # of particles/Liters of water
Molarity= # of moles / Liters of water
Tonicity= numbers of solutes that cannot cross the plasma membrane/Liters of water. |
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Term
| What organ in annelids is equivalent to the mammalian nephron? |
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Definition
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