M104 T3 L4 Flashcards
What percentage of filtered water is reabsorbed in the PT?
about 65%
What percentage of filtered Na+ is reabsorbed in the PT?
about 65%
What is the relationship between the amount of filtered Na+ reabsorbed in the PT and that of water?
they are equal - the amount of sodium reabsorbed matches the amount of water reabsorbed
Why is it that the amount of sodium reabsorbed matches the amount of water reabsorbed?
bc water likes to follow sodium
any sodium reabsorbed back into the blood is followed by water in the same proportion
What percentage of filtered electrolytes are reabsorbed in the PT?
about 60-70%
Why is the reabsorption movement of negatively charged mlcs related to that of sodium ion?
bc the negative mlcs are attracted to the positive charge of Na+
What enzyme regulates the reabsorptive movement of hydrogen carbonate?
carbonic anhydrase
What are the two types of nephrons?
cortical - 85%
juxtamedullary - 15%
What is the difference between the two types of nephrons?
cortical are deep in the renal cortex
juxtamedullary - lie in the renal cortex close to the renal medulla
What occurs in the LoH?
tubular fluid is further modified so that urine is concentrated even further
What are the two stages of concentration in the LoH?
the extraction of water in the descending limb (D)
the extraction of Na+ and Cl- in the ascending limb (A)
What type of nephron is the process of concentration more important for?
juxtamedullary nephrons bc they have longer loops of Henle
What are features of the cells in the thin descending part of the LoH?
present in a thin layer of cells
lots of aquaporin-1 pumps
the cells are flat
there’s no active transport of salt
What is the movement of water like in cells in the thin descending part of the LoH?
there is some passive movement of water via tight junctions
there are lots of aquaporin-1 pumps that make this section of the nephrons permeable to water
