Ch 48 Osmoregulation And Disposal Of Metabolic Wastes Flashcards
(22 cards)
What is the most abundant molecule?
Water.
What is the direction of water flow in freshwater fishes? From inside to outside? Or water flows from outside to inside?
Water flows from outside to inside since salt is greater inside
How is osmotic shock prevented in freshwater fishes?
Scales and mucous coatings
How do freshwater fishes have the ability to excrete a large volume of hypotonic urine?
Kidneys have large glomeruli
What are glomeruli?
Capillary clusters that filter the blood and produce urine
How do freshwater fishes retain minerals they’ve lost?
Salt is actively transported back into the body by gills.
What do gills excrete?
Ammonia (only 10% of urea)
What type of animals must also actively transported salt into the body?
Amphibians
What is the general important of hypotonic urine?
Reabsorption of solutes without significant reabsorption of water
How is the urine of marine bony fish
Isotonic urine
What is the direction of water flow in marine fishes?
From inside to the outside of the body.
How do marine waters compensate for their lost water?
Drink sea water, secrete salt through gills
What is gills responsible for in marine fish?
Excretion of ammonia
How is the glomeruli in marine fishes?
Very little to none- little urine is excreted
Why is urine acidic?
Potassium and hydrogen ions
What is the important structure in podocytes ?
Basement membrane
Why is Hugh concentration of potassium in the blood a problem?
Since potassium prevents depolarization so muscles remain contracted (including diaphragm, heart..)
What is the importance of aldosterone?
Regulates tubular potassium secretion.
Why should aldosterone be moderate?
Because extra elimination of potassium leads to sodium retention -> water retention -> high BP
Why is reabsorption of water important?
Regulation of blood pressure, cardiac output and ion transport
What percentage of reabsorption occurs in the proximal convoluted tubule?
65%
What does concentrated urine depend on?
High concentration of salt (NaCl) and urea in the interstitial fluid of the renal medulla.
