Q2 final: Acids + bases

Question 1

what is neutral pH, plasma pH, and venous vs arterial?

Answer 1

neutral = 7

plasma= 7.4 (7.35-7.45)

venous - slightly below 7.4

arterial- slightly above 7.4

Question 2

how does co2 supply H+

whats the other H+ source

Answer 2

co2 + h2o-> h2co3 -> H+ + HCO3-

carbonic anhydrase enzyme makes h2co3 from co2 and h2o

other sources; production of inorganic and organic acids by metabolism

Question 3

what are the 3 lines of defense for resisting [H] changes & how fast do they act?

Answer 3

1. chemical buffer systems : immediate
2. Respiratory control; a few minutes
3. Renal control; hours to days

Question 4

what is the primary ECF buffer?

Answer 4

H2co3 / HCO3- buffering system. major determinent of plasma ph. (primary against noncarbonic acid changes)

Question 5

what is the primary ICF buffering system

Answer 5

protein buffer system. also helps with ECF

Question 6

what is the primary buffer against carbonic acid changes

Answer 6

hemoglobin buffer system

Question 7

what is the main urinary buffer

Answer 7

phosphate buffer system. it also buffers the ICF

Question 8

how does ventilation change with metabolic aklalosis/acidosis

Answer 8

acidosis- ventilation increases

alkalosis- ventilation decreases

Question 9

how does the rate of CO2 removal by the lungs change with metabolc acidosis/alkalosis

Answer 9

increases with acidosis, decreases with alkalosis

Question 10

how does the rate of h+ generation from co2 change with metabolic acidosis and alkalosis

Answer 10

it increases with alkalosis and decreases with acidosis

Question 11

what is the most potent acid/base regulatory system n the body; what 3 things does it do

Answer 11

the renal system

• h+ secretion
• HCO3- reabsorption
• NH3 secretion

Question 12

whats the pH of urine

Answer 12

4.6-8, average is 6

Question 13

where is na reabsorbed mostly and through what type of channel? where does the energy come from ?

Answer 13

proximal tubule, reabsorbed through Na-H antiporter at the luminal membrane.
-Na-K atpase at basolateral side (blood side) provides the energy

-na is also reabsorbed through the Na-HCO3’ symporter

Question 14

how does H+ get secreted/whcih channels? what is it linked to?

Answer 14

H+ atpase pump, H-K atpase pumps in type A intercalated tubular cells in the distal and collecting tubules, partly linked to K reabsorption. Also through the Na-H antiporter it is partly linked to Na reabsorption (where does this occur?)

Question 15

how does hco3 get reabsorbed

Answer 15

hco3 gets filtered as hco3,, turned into H2o and co2 in the tubular lumen by carbonic anhydrase in the lumen (membrane bound). h20 and co2 diffuse into cells of the tube (type a intercalated tubular cells) and then in the cell it can be turned back into hco3- which can be reabsorbed.

Question 16

how much hco3 gets reabsorbed

Answer 16

the amount that gets filtered equals the amount that gets reabsorbed!
secreted H+ couples with hco3 and forms h2co3-> co2 and h20 which diffuses into thecells of the tubule (then converted back to hco3- in the cell and reabsobred as that

Question 17

what else does H+ secreted into tube lumen couple with

in addition to HCO3

Answer 17

phosphate, another urinary buffer. it couples with Hpo4 to make h2po4-, and gets EXCRETED that way. (dihydrigen phosphate)

Question 18

where is hco3 from cellular metabolism reabsorbed

Answer 18

at proximal tubule, distal and collecting tubule. co2 from cell metabolism joins with OH from water, hco3-> reabsorbed

Question 19

how is NH3 secreted from glutamine. where does it primarily occur? whats this called?

what occurs with every NH4 that gets excreted?

Answer 19

each glutamine is metabolized and turned into 2 nh3 (ammonias) ammoniagenesis !!-mainly occurs in the proximal tubule.
-secreted nh3 binds w/H and forms NH4. for every NH4 excreted, a new hco3 is reabsorbed (this might be because the H is coming from H2co3 that forms hco3 and H in tube cells then secretes the H and the hco3 gets reabsorbed ?

Question 20

how does HCO3 change with acidosis/alkalosis? (secretion, excretion and reabsorption)

Answer 20

its reabsorption increases with acidosis (its a base) and its reabsorption decreases with alkalosis.
-excretion stays the same with acidosis which means all that is filtered gets reabsorbed. but with alkalosis, excretion starts to occur

Question 21

what is pk? whats the pk of h2co3

Answer 21

the log of 1k (k is the dissociation constant)

pk of h2co3-6.1

Question 22

whats the henderson hasselbach equation

Answer 22

pH = pK + log (BASE/acid)

for hco3/co2 its log [hco3]/[co2]

normal [hco3]/[co2] is 20/1 in the blood where

7.4=6.1 + log (x)

logx = 1.3

Question 23

what are the causes of respiratory acidosis

Answer 23

hypoventilation

• obstruction of airway
• copd
• reduced respiratory muscle ability

Question 24

in uncompensated RESPIRATORY acidosis what happens to the co2/hco3 levels?

Answer 24

co2 is increased and hco3 is the same as normal

Question 25

in compensated respiratory acidosis what happens to co2 and hco3 levels

Answer 25

co2 increases, hco3 increases to get to 20/1 ratio of hco3/co2

Question 26

in uncompensated respiratory alkalosis/ compensated resp alkalosis, what happens to co2 and hco3

Answer 26

uncompensated ; co2 is decreased, hco3 is normal

compensated; co2 decreased, hco3 decreased

Question 27

in uncompensated/compensated METABOLIC acidosis- what are co2 and hco3? how does it work for metabolic alkalosis

Answer 27

uncompensated: hco3 decreases, co2 stays the same as normal

compensated; hco3 decreases, co2 decreases

meta alkalosis; hco3 changes, co2 adjusts just like this (you get it)

Question 28

what can cause respiratory alkalosis

Answer 28

panic attacks, high altitude

Question 29

what are the causes of metabolic acidosis?

Answer 29

• diarrhea(loss of HCO3)
• diabetes mellitus (keto acdi accumulation)
• strenuous exercise - lactic acid accumulation
• uremic acidosis - H accumulation

Question 30

what are the causes of metabolic alkalosis

Answer 30

• vomiting (loss of H+)

- renal disease - HCO3 accumulation