3 - Basics - Acid-Base - 1/2 Done

Front 1

_______ is a substance that when disolved in H2O, yeilds hydrogen (H+) ions.

Back 1

An acid

Front 2

Balanced plasma concentrations of hydrogen and bicarb ions regulate these 4 things...

Back 2

1. enzyme activity
2. hemoglobin saturation
3. myocardial contractility
4. intracellular chemical rxns

Front 3

An acid is a ____ donor.

Back 3

proton
(H+)
HCL --> H + Cl-

Front 4

______ is a substance that when disolved in H2O yields a hydroxide ion (OH-)

Back 4

A base

Front 5

Bases are proton ____

Back 5

acceptor since they remove hydrogen from a solution
NaOH --> Na + OH-

Front 6

Hydroxide ions have a stong affinity for _____ ions.

Back 6

hydrogen

Front 7

How are hydrogen ions produced?

Back 7

produced as substrates and oxidized in the production of ATP

Front 8

What is normal hydrogen concentration in arterial blood?

Back 8

35-45
equiv to pH of 7.35-7.45

Front 9

What is normal plasma bicarb lvl?

Back 9

24+/- 2 mEq/L

Front 10

The value of pH is inversely related to the level of free hydrogen ions...in other words...

Back 10

the lower the pH the higher the level of free hydrogen ions

Front 11

A change of 1 pH unit actually represents a _____ change in free H+ lvl.

Back 11

10-fold

Front 12

fluctuations in normal blood pH interfere with these 3 things:

Back 12

1. shape and function of hormones and enzymes
2. distribution of electrolytes
3. responses of excitable membranes in the heart, nerves, skele muscles, GI tract

Front 13

a person could not survive long with a pH below ____ or above ___

Back 13

6.8
7.7

Front 14

What is a quantitative measurement describing the equilibrium b/w plasma pH and the ratio of plasma pCO2 and HCO3?

Back 14

Henderson-Hasselbach Equation

Front 15

What is the primary determinant of pH?

Back 15

the ratio of pCO2 to HCO3 (not indiv. values)

Front 16

The body tries to maintain a constant pH, so the ratio of HCO3 to dissolved CO2 remains...

Back 16

20:1 (pH 7.4)
HCO3:CO2

Front 17

What is the most powerful system for acid-base regulation?

Back 17

the kidneys

The renal response takes 12-48 hrs for complete correction

Front 18

What are the 4 buffering systems?

Back 18

1. bicarb
2. hemoglobin
3. protein
4. phosphate

Front 19

What is the most impt buffering system in the ECF?

Back 19

carbonic acid-bicarb buffering system

Front 20

What is the 2nd most impt buffering system (it is intracellular)

Back 20

hemoglobin buffering system

Front 21

What is a buffering system in the ICF (minimal role) and the urine?

Back 21

phosphate buffering system

Front 22

What buffering system regulates pH in the ECF and ICF?

Back 22

protein buffering system

Front 23

In this primary buffering system, hydration of CO2 to carbonic acid in the plasma and erythrocytes occurs and bicarb ions enter the plasma, H+ ions are buffered by reduced hemoglobin

Back 23

Bicarb buffering system

CO2+H2O <--> H2CO3 <--> H + HCO3-

Front 24

Bicarb is a weak _____, and carbonic acid is a weak ___

Back 24

base
acid

Front 25

In the 2nd most important buffering system, CO2 diffuses into the erythrocytes down a concentration gradient.

Back 25

Hemoglobin buffering system

The H ions bind to Hb and the bicarb ions are exchanged back into plasma with extracellular Cl.

Front 26

What is it called when bicarb ions are exchanged with cl ions to maintain electrical neutrality?

Back 26

chloride shift

Front 27

In this buffering system, proteins in the ICF and the ECF serve as buffers. They bind or release free H ions prn.

Back 27

Protein buffering system

Front 28

What protein is the most impt in the ECF protein buffering system?

Back 28

Albumen

in the ICF its Hb

Front 29

How long does it take for a ventilatory response?

Back 29

1-5 min

Front 30

Peripheral chemoreceptors in the ________, respond to changes in CO2.

Back 30

carotid bodies

Front 31

Central chemoreceptors in the ______ respond to changes in CSF pH

Back 31

medulla

- respond to change in H+ ions, not CO2

Front 32

Alveolar ventilation increases ____L/min for each 1mmHg increase in PaCO2

Back 32

1-4

Front 33

What are the 3 impt renal responses?

Back 33

1. increased reabsorption of HCO3
2. Increased excretion of H ions
3. Increased production of ammonia

Front 34

How much bicarb is filtered at the glomerulus?

Back 34

all of it

Front 35

How much bicarb is reabsorbed in the proximal tubule?

Back 35

85-90%
(not normally excreted in urine)

Front 36

What occurs in the tubular lumen to form carbonic acid?

Back 36

H+ ions combine with Bicarb ions.

Front 37

In the tubular lumen the enzyme carbonic anhydrase dissociates _______ to CO2 and H2O.

Back 37

carbonic acid (H2CO3);
the CO2 and the H2O diffuse into the tubular cell where they go back to carbonic acid. which later dissociate to H and bicarb

Front 38

what is actively secreted into the tubular lumen?

Back 38

H+

Front 39

_____ is transported by Na into the peritubular capillary blood.

Back 39

Bicarb

Front 40

For each H+ ion that the kidney excretes there is a generation of one new ____
ion added to the ECF

Back 40

HCO3-

Front 41

What is an important urinary buffer?

Back 41

Hydrogen phosphate (excreted after all the HCO3 is reclaimed)

Front 42

where is ammonia formed?

Back 42

within the mitochondria of proximal tubular cells - deamination of glutamine

Front 43

Acidemia ____ renal production of NH3

Back 43

increases

Front 44

Does ammonia actively or passively enter the tubular fluid?

Back 44

passively