Cremo 1: Fundamentals of body buffers and gases

Question 1

What is the concentration of H+ ions in a healthy individual?

Answer 1

35 and 45 nM

Question 2

Normal range for pH

Answer 2

7.35-7.45

Question 3

Acid production originates intracellularly. What is the average intracellular pH?

Answer 3

7

Question 4

Non bicarbonate buffers

Answer 4

hemoglobin
plasma proteins
phosphates

Question 5

This has the highest buffer capacity of non-volatile buffers

Answer 5

hemoglobin

Question 6

What two things does buffering capacity depend on?

Answer 6

1. concentration of the buffer

2. PKA (how close is the PKA to 7.4?)

Question 7

Hemoglobin has abundant (blank) side chains, therefore it has a PKA of about (blank)

Answer 7

histidine; 6.5

Question 8

Plasma proteins have about (blank) percent of the buffering capacity of Hb

Answer 8

20%

Question 9

The most plentiful plasma protein

Answer 9

Albumin

Question 10

An important buffer in the renal tubular filtrate

Answer 10

Phosphate

Question 11

List the non-bicarbonate (non-volatile) buffers in order of buffering capacity

Answer 11

1. hemoglobin
2. plasma proteins
3. phosphate

Question 12

What is the most important function of the non-volatile buffers?

Answer 12

Mitigate pH changes due to changes in volatile acid (CO2)

Question 13

Can the bicarbonate system mitigate changes in the levels of CO2?

Answer 13

No! Non-volatile buffers are the only ones that can do this.

Question 14

Most powerful buffer of the ECF

Answer 14

Bicarbonate buffer system

Question 15

Atmospheric pressure

Answer 15

760mmHg

Question 16

Total of partial pressures (barometric pressure) at sea level? Total of partial pressure in Reno?

Answer 16

760mmHg; 680mmHg

Question 17

Partial pressure of CO2.

Answer 17

0.23mmHg

Question 18

Clinical PCO2

Answer 18

Zero (0.23 at sea level)

Question 19

PO2 at sea level? In Reno?

Answer 19

159mmHg; 143mmHg

Question 20

In an unopened bottle of soda water, the partial pressure of the gas above the liquid is

Answer 20

the same as the liquid.

Question 21

The partial pressure of a gas dissolved in a liquid is the partial pressure of that gas which would be generated in a gas phase (blank) with the liquid.

Answer 21

in equilibrium

Question 22

Gases always travel down (blank) gradients, but may or may not travel down (blank) gradients.

Answer 22

partial pressure gradients; concentration gradients

Question 23

What does Henry’s law quantify?

Answer 23

How much gas is dissolved in a liquid

Question 24

What’s the formula for Henry’s law?

Answer 24

P•KH = C = Concentration

Where KH is different for each gas.

Question 25

At equilibrium, the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid.

Answer 25

Henry's law

Question 26

K acid equation for the bicarbonate buffer system

Answer 26

K = ([H+][HCO3-])/CO2

Question 27

Simplified bicarbonate buffer system

Answer 27

CO2 H+ + HCO3-

Question 28

Normal concentration of bicarbonate in the body in a healthy individual

Answer 28

24mM

Question 29

In a healthy individual, the ratio of bicarbonate to CO2 is...

Answer 29

20

Question 30

The Henderson equation

Answer 30

Kacid = ([H+][HCO3-])/PaCO2

Question 31

Normal [H+] concentration Normal [HCO3-] concentration Normal PaCO2

Answer 31

40nM 24mM 40mmHg

Question 32

When a sample of whole blood is exposed to an increased PCO2, what will happen?

Answer 32

This will shift the equilibrium to the right, increasing H+ and HCO3-

Question 33

Henderson Hasselbalch Equation for clinical use

Answer 33

pH = 6.1 + log [HCO3-]/(0.3*PaCO2)

Question 34

Rearranged Henderson equation to solve for [H+]

Answer 34

(24 * PaCO2)/HCO3- = [H+]

Question 35

The bicarbonate system is open to the atmosphere, so it allows for the removal of (blank) to give effective buffering even though the PKA of 6.1 is far from 7.4

Answer 35

CO2

Question 36

What kind of buffers responds to changes in CO2?

Answer 36

Non-volatile buffers, like hemoglobin

Question 37

Describe what happens when Hb is present during hypoventilation.

Answer 37

During hypoventilation, there is an increase in the PCO2, so the system produces more H+ and more HCO3-. Hb can act as a buffer by pulling out some of the H+ to make HbH+.

Question 38

Is a shift in equilibrium equal to a buffering effect?

Answer 38

No!

Question 39

Two main processes that acidify the body

Answer 39

1. Metabolism produces CO2 | 2. Endogenous acid production

Question 40

Does metabolism consume bicarbonate? Does endogenous acid production consume bicarbonate?

Answer 40

No; Yes

Question 41

Major source of metabolic acid production

Answer 41

Eating protein

Question 42

Industrialized diets (high in meat and eggs) have (blank) rates of metabolic acid production, while non-industrialized diets (more fruits and veggies) have (blank) rates of metabolic acid production.

Answer 42

high; low

Question 43

Compare the daily production of CO2 to the daily production of metabolic acid

Answer 43

Daily CO2>>>>metabolic acid | Volatile acid is about 100 times that of non-volatile.

Question 44

Acid secreted by the gut into the blood

Answer 44

Gastrointestinal acid production

Question 45

Does GAP consume bicarbonate?

Answer 45

yes

Question 46

(blank) serves as a buffer for gastrointestinal acid production

Answer 46

Bicarbonate system

Question 47

In the upper gut, (blank) enters the lumen of the gut, while (blank) is pushed out into the bloodstream. In the lower gut, (blank) enters the lumen of the gut and (blank) is pushed out into the bloodstream.

Answer 47

H+, HCO3- | HCO3-, H+

Question 48

On balance, the gut secretes slightly more (blank) into the blood stream than (blank)

Answer 48

H+ ; HCO3-

Question 49

Endogenous acid production equation

Answer 49

EAP = MAP + GAP

Question 50

Prolonged vomiting can lead to metabolic (blank), while diarrhea can lead to prolonged metabolic (blank).

Answer 50

alkalosis; acidosis

Question 51

Vomiting causes (blank) to leave the stomach lumen, and (blank) to enter the blood.

Answer 51

H+ ; bicarbonate

Question 52

Diarrhea causes (blank) to leave the stomach lumen, and (blank) to enter the blood.

Answer 52

bicarbonate; H+