Ch. 44 - Osmoregulation and Excretion Flashcards
big ideas: kidney A&P, osmoconformers/regulators, kidney gradients, and how hormones affect the kidneys
what is osmoregulation?
the regulation of the solutes of body fluids [maintaining salt / water concentration]
what is excretion?
the removal of metabolic wastes from body fluids
what is osmolarity?
the measure of the solute concentration in a volume of solvent
what is an osmoconformer?
an organism in which the osmolarity varies with its environment
what traits are common of osmoconformers?
-live in places with constant osmolarity
-spend little energy maintaining ion gradients
what are osmoregulators?
organisms that maintain their solute concentration around a set point
what osmoregulation happens in a hypoosmotic environment?
-water diffuses in, so salts must be pumped in
what osmoregulation occurs in a hyperosmotic environment?
-water diffuses out, so salts must be pumped out
-must spend energy to maintain constant osmolarity
how does shark osmoregulation differ from marine fish?
shark cells have a salt concentration typical to fish, but they concentrate urea = slightly hyperosmotic = water moves into sharks
what osmoregulatory strategies do marine animals use?
-water is constantly moving out & salts in
-fish need to conserve water & remove salts
-active transport of Cl- out of gills, Na follows, urine is very concentrated
what osmoregulatory strategies do freshwater animals use?
-water is constantly moving in & salts out
-fish need to conserve salts & remove water
-pump Cl- into gills, Na+ follows, urine is very dilute
what osmoregulatory strategies do terrestrial animals use?
body coverings [skin/fur]
kidneys to conserve water
-behavior [avoiding heat]
what are the three main types of nitrogenous waste?
ammonia/NH3, urea, and uric acid
how is ammonia eliminated from fresh water fish?
ammonia is not converted into any other compound, it is diluted with water and excreted as is
how is ammonia removed from mammals and amphibians?
ammonia is converted to urea, which is then eliminated through excretion
how is ammonia eliminated in reptiles and birds?
ammonia is converted to uric acid, which is then eliminated in waste
what are the three portions of the kidney?
the outer cortex, inner medulla, and renal pelvis
what kidney component is found in the outer cortex?
the glomerulus of the nephron
what kidney components are found in the inner medulla?
-the nephron loop and collecting ducts which form the renal pyramids
what is the nephron?
the smallest functional unit of a kidney, which produces urine
what are the five main structures found in the nephron?
- glomerulus
- proximal convoluted tubule
- nephron loop
- distal convoluted tubule
- collecting duct
what is the function of the glomerulus?
-to collect fluid filtered from the blood
-also begins formation of the filtrate [what becomes urine]
what is the function of the proximal convoluted tubule?
-where reabsorption of nutrients and water begins
-some wastes and things not filtered from the glomerulus are secreted here
what is the function of the nephron loop?
to establish a concentration gradient and further remove water and ions from the nephron
