Lecture 19 Renal Acid Base Regulation

Question 1

acid

Answer 1

compounds that release H+ ions

Question 2

strong acid

Answer 2

completely dissociates

Question 3

weak acid

Answer 3

incompletely dissociates

Question 4

volatile acids

Answer 4

acids excreted from lungs (i.e. CO2)

Question 5

nonvolatile acids

Answer 5

acids excreted from the kidneys (i.e. phosphoric, sulfuric, keotacids, lactic acids)

Question 6

what is the pH range for venous blood?

Answer 6

7.35-7.45

Question 7

what is the pH range for arterial blood

Answer 7

7.37-7.44

Question 8

what are the systems in the body that regulate pH

Answer 8

chemical acid base buffer systems in body fluids
respiratory system
kidneys

Question 9

buffer

Answer 9

substance that can reversibly bind to H+

Question 10

buffer systems

Answer 10

bicarbonate buffer system
phosphate buffer system
protein buffers

Question 11

which buffer system is the most important extracellular system?

Answer 11

bicarbonate

Question 12

bicarbonate buffers system

Answer 12

consists of a weak acid and a bicarbonate salt

mainly regulated by the kidneys

Question 13

addition of a strong acid to bicarbonate buffers system

Answer 13

leads to the formation of a weak acid

(strong acid + HCO3- –> H2CO3 –. CO2

Question 14

addition of strong base to bicarbonate buffer system

Answer 14

leads to the formation of weak base

Question 15

what organ is the primary regulator of the bicarbonate buffer?

Answer 15

the kidneys

Question 16

metabolic acid base disorders

Answer 16

primary change in [bicarbonate] in extracellular fluid

Question 17

metabolic acidosis

Answer 17

decrease in HCO3 - in fluid

Question 18

metabolic alkalosis

Answer 18

increase in HCO3- in fluid

Question 19

respiratory acid base disorders

Answer 19

result from a primary change in CO2 in blood

Question 20

respiratory acidosis

Answer 20

increase in CO2

Question 21

respiratory alkalosis

Answer 21

decrease in CO2

Question 22

pH point for bicarbonate buffer and the pKa

Answer 22

the normal pH is 7.4 so there is 20x as much bicarbonate buffer in system in form of HCO3 than CO2

Question 23

what is the pKa of bicarbonate buffer?

Answer 23

6.1

Question 24

what is the primary method for removing nonvolatile acids?

Answer 24

renal excretion

Question 25

what must happen before filtered bicarbonate is reabsorbed

Answer 25

must react with H+ to form carbonic acid

Question 26

three mechanisms for kidneys to regulate H+

Answer 26

1. reabsorb filtered bicarbonate ions
2. secrete hydrogen ions
3. produce new bicarbonate ions

Question 27

bicarbonate ion is reabsorbed in which part of kidney

Answer 27

proximal tubule

Question 28

where does H+ secretion vie PRIMARY active transport occur

Answer 28

intercalated cells of late distal tubule

Question 29

where does H+ secretion via SECONDARY active transport occur

Answer 29

all parts of tubule except ascending and descending thin limbs

Question 30

describe bicarbonate ion reabsorption

Answer 30

H+ + HCO3 form carbonic acid
carbonic acid breaks down to form CO2 and H20
CO2 goes to tubular cells and forms carbonic acid after combining with water
carbonic acid breaks down to H+ and HCO3-
bicarbonate ion diffuses from basolateral membrane into intersistial fluid then blood

Question 31

carbonic anhydrase

Answer 31

from carbonic acid from CO2 and water

necessary for bicarbonate reabsorption

Question 32

how is bicarbonate normally titrated?

Answer 32

each time a H+ ion is formed there is a bicarbonate formed and released in the blood

Question 33

how is bicarbonate titrated in acidosis

Answer 33

new bicarbonate ion is added to extracellular fluid

Question 34

how is bicarbonate ion titrated in alkalosis

Answer 34

bicarbonate ions are removed from ECF via renal excretion

Question 35

how do the kidneys handle excess base

Answer 35

reabsorbs all the filtered bicarbonate ions (same as adding H+ to ECF) so that the fluid returns to normal

Question 36

how do lungs cause acidosis? compensatory method?

Answer 36

increase [CO2]

compensate by increasing plasma bicarbonate via addition of new bicarbonate from kidney

Question 37

how do lungs cause alkalosis? compensatory method?

Answer 37

decrease [CO2] (hyperventilation)

compensate by decreasing plasma bicarbonate via renal excretion