lecture 19 (T3): renal acid-base regulation

Question 1

which buffer system is most important in buffering renal tubular fluid

Answer 1

phosphate buffer system

Question 2

compounds that dissociate incompletely into hydrogen ions and a conjugate base are members of what compound

Answer 2

weak acids

Question 3

bicarbonate buffer system consists of ____ and _____

Answer 3

bicarbonate salt and weak acid

Question 4

what occurs when there is a decrease in bicarbonate ion results in a decrease in the ratio of bicarbonate ion to carbon dioxide in the extra cell fluid

Answer 4

metabolic acidosis

Question 5

what is respiratory alkalosis due to a decrease in carbon dioxide concentration caused by hyperventilation compensated by

Answer 5

renal excretion of bicarbonate ion

Question 6

where does primary active hydrogen secretion involving a hydrogen-transporting ATPase occur

Answer 6

late distal tubule in intercalated cells

Question 7

where does most bicarbonate reabsorption occur

Answer 7

proximal tubule

Question 8

where is volatile acid excreted from

Answer 8

lungs

Question 9

where is nonvolatile acids excreted form

Answer 9

kidneys

Question 10

what are some major systems regulated H+ concentration

Answer 10

chemical acid-base buffer systems of the body fluids
respiratory center
kidneys

Question 11

define buffer

Answer 11

substance that can reversibly bind H+

Question 12

what does addition of a strong acid lead to in the bicarbonate buffer system

Answer 12

formation of a weak acid

Question 13

what does addition of a strong base to the bicarbonate buffer system lead to

Answer 13

formation of weak base

Question 14

what excretes the increases levels of HCO30 in the bicarbonate buffer system

Answer 14

kidneys

Question 15

what do decreased CO2 levels in the bicarbonate buffer system do to respiration rate

Answer 15

decreases it

Question 16

what is bicarbonate concentration regulated primarily by in the bicarbonate buffer system

Answer 16

kidneys

Question 17

what is the pCO2 controlled by in the bicarbonate buffer system

Answer 17

rate of respiration

Question 18

what is the most important extracellular buffer system

Answer 18

bicarbonate buffer system

Question 19

what do metabolic acid base disorders primarily result form

Answer 19

change in bicarbonate concentrations in extracellular fluid

Question 20

what does respiratory acid base disorders primarily result from

Answer 20

change in pCO2

Question 21

why is phosphate buffer system important

Answer 21

plays major role in buffering tubular fluid and intracellular fluids

Question 22

why is the phosphate buffer system important in the kidneys (2 reasons)

Answer 22

usually becomes greatly concentrated in the tubules

lower pH of the tubular fluid brings the operating range of the buffer closer to the pk of the buffer system

Question 23

what is the primary method for removing nonvolatile acids

Answer 23

through renal excretion

Question 24

what are mechanisms for regulating extracellular H+

Answer 24

kidneys reabsorb filtered extracellular H+
kidneys can secrete hydrogen ions
kidneys produce new bicarbonate ions

Question 25

where does hydrogen ion secretion via secondary transport occur

Answer 25

almost all parts of the tubules except descending and ascending thin limbs of the loop of henle

Question 26

where does bring active hydrogen secretion begin

Answer 26

in the late distal tubules in intercalated cells and involves a hydrogen-transporting ATPase

Question 27

where does the majority of bicarbonate reabsorption occur

Answer 27

proximal tubule

Question 28

why is carbonic anhydrase necessary

Answer 28

it is necessary for the formation of carbonic acid from carbon dioxide and water

Question 29

how is incomplete titration used to correct acidosis

Answer 29

in metabolic acidosis, new bicarbonate ion is added to the extracellular fluid

Question 30

how is incomplete titration used to correct alkalosis

Answer 30

in metabolic alkalosis, bicarbonate ions are removed form the extracellular fluid by renal excretion

Question 31

how does the tubular epithelium secretion hydrogen ion

Answer 31

via primary active transport

Question 32

what is active transport resulting in hydrogen ion secretion carried out by

Answer 32

intercalated cells

Question 33

how does hydrogen ion secretion in the proximal tubule occur

Answer 33

via secondary sodium-hydrogen counter-transport

Question 34

where are the sodium-hydrogen exchanges located

Answer 34

on the apical (luminal) membranes of the renal epithelial cells

Question 35

where are sodium-potassium-ATPase exchangers found

Answer 35

basal membranes

Question 36

what is the lower limit of pH that can be achieved in normal cells

Answer 36

4.5

Question 37

how are nonvolatile acids primarily removed

Answer 37

via renal excretion

Question 38

what is the minimal urine pH

Answer 38

4.5

Question 39

how are excess hydrogen ions eliminated

Answer 39

through binding with phosphate or ammonia ions

Question 40

how do the kidneys correct alkalosis

Answer 40

failing to reabsorb all the filtered bicarbonate ions or adding hydrogen ion to the extracellular fluid

Question 41

what happens when there is a decreases in the ration of bicarbonate ion to carbon dioxide in extracellular fluid

Answer 41

decrease in bicarbonate ion: metabolic acidosis | increase in CO2: respiratory acidosis

Question 42

what is the primarily compensatory response to respiratory acidosis

Answer 42

increase in plasma bicarbonate ion due to addition of new bicarbonate by the kidney

Question 43

what is the primary compensatory response to metabolic acidosis

Answer 43

increase in ventilation rate

Question 44

what is the renal compensation to metabolic acidosis

Answer 44

adds new bicarbonate ion to extracellular fluid

Question 45

in alkalosis, how is excess bicarbonate excreted

Answer 45

in urine

Question 46

what is respiratory alkalosis caused by

Answer 46

hyperventilation

Question 47

what is the compensatory response to respiratory alkalosis

Answer 47

reduction in plasma bicarbonate ion concentration caused by renal excretion of bicarbonate ion

Question 48

what is metabolic alkalosis caused by

Answer 48

rise in the extracellular fluid bicarbonate ion concentration

Question 49

what is the compensatory response to metabolic alkalosis

Answer 49

decreased ventilation | increased renal bicarbonate ion excretion