LIN Q's [Acids, Bases, and Buffers]

Question 1

what are the 3 important homeostatic regulators of acid-base balance (in the order of response)?

Answer 1

1) chemical buffer systems
2) respiratory mechanism
3) renal mechanism

Question 2

acid

Answer 2

tends to donate a proton

Question 3

base

Answer 3

tends to accept a proton

Question 4

what are the characteristics of chemical buffer systems?

Answer 4

• first to respond
• bicarbonate; phosphate; protein buffer systems
• remove excess acids or bases
• takes < 1 sec (acid/base neutralization & equilibrium shifting)

Question 5

what are the characteristics of respiratory mechanism?

Answer 5

• 2nd to respond
• takes 1-3 min
• respiratory center involved
• removes carbon dioxide and therefore H2CO3 (carbonic acid)

Question 6

what are the characteristics of renal mechanism?

Answer 6

• 3rd to respond bu most potent
• takes hours to days
• kidneys remove metabolic acids (Pi, uric & lactic acids, ketone bodies)

Question 7

what is the Kd of pure water?

Answer 7

1.8 * 10^-16 M

Question 8

what is Kw of water at 25 degrees C?

Answer 8

1 * 10^-14

Question 9

strong acid

Answer 9

dissociate completely in solution

Question 10

weak acid

Answer 10

dissociate to only a limited extent

Question 11

what is the Ka of an acid?

Answer 11

it is the dissociate constant of an acid; the tendency of the acid to dissociate and donate a H+ ion; equation: Ka= [H+[A-]/[HA]

Question 12

what is Henderson-Hasselbalch equation?

Answer 12

estimate the pH of a solution of an acid when pKa is known; the pH of a buffer system is controlled by [A-]/[HA]; equation: pH=pKa + log([A-]/[HA])

Question 13

when does the weak acid tend to dissociate?

Answer 13

when the pH > pKa

Question 14

Le Chatelier’s Principle

Answer 14

if a dynamic equilibrium is distributed by changing the conditions, the position of equilibrium ives to counteract the change

Question 15

[HIGH YIELD] what determines plasma pH?

Answer 15

either concentration of bicarbonate or the PaCO2

Question 16

what is the plasma pH that is maintained by renal and respiratory systems? and what buffer ratio causes this plasma pH?

Answer 16

plasma pH= 7.4 when buffer ratio= 20/1

Question 17

what would happen if the pH is still low after acid is added in the bicarbonate buffer system?

Answer 17

the H+ will rise and removed by the kidneys.

the HCO3- will be retained by the kidneys.

Question 18

what are some characteristics of protein buffer system?

Answer 18

• work in both ICF & ECF
• amino groups accept a proton
• carboxyl groups donate a proton
• side chain can be partially deprotonated

Question 19

protein buffer system: what has histidines?

Answer 19

albumin (in ECF) and Hb (in ICF)

Question 20

protein buffer system: what are the most important buffer groups of proteins?

Answer 20

imidazole groups of histidine

Question 21

acidosis and alkalosis is due to imbalance of what?

Answer 21

PaCO2 and [HCO3-]

Question 22

what causes respiratory acidemia?

Answer 22

decrease in pH due to increase in CO2

Question 23

what causes respiratory alkalemia?

Answer 23

increase in pH due to decrease in CO2

Question 24

what causes metabolic alkalemia?

Answer 24

increase in pH due to increase in HCO3-

Question 25

what causes metabolic academia?

Answer 25

decrease in pH due to decrease in HCO3-

Question 26

Davenport Diagram

Answer 26

a graphical tool that helps a physician or investigator to diagnose the causes of acidosis and alkalosis; a specific area in the diagram represents a specific disorder

Question 27

what do the buffer systems in our body control?

Answer 27

changes in [HCO3-] and pH

Question 28

what are the three buffer systems talked about in class?

Answer 28

1) bicarbonate buffer system
2) phosphate buffer system
3) protein buffer system

Question 29

phosphate buffer system

Answer 29

• intracellular buffer

- phosphate anion dissociates to generate H+ and the conjugate base, mono hydrogen phosphate with a pKa of 7.2

Question 30

which diseases lead to metabolic acidosis?

Answer 30

• diabetes
• heart failure
• renal failure
• diarrhea

Question 31

what can cause metabolic alkalosis?

Answer 31

• vomitting

- ingestions of soda (NaHCO3)

Question 32

T/R the renal regulator can retain bicarbonate to increase the plasma pH

Answer 32

TRUE