Final Exam - Acid/Base I

Question 1

What is the cabin pressure typically kept at on a plane at high level?

Answer 1

Mimcs the atmosphere at 8,000 ft

Question 2

At high elevation, what effects would you expect on the right heart?

Answer 2

• At high elevation there is a low pO2
• This leads to a decreased alveolar concentration, leading to HPV
• HPV increases the resistance that the RH has to pump against and increases RH strain

Question 3

Describe what happens to gas exchange if a plane’s cabin depressurized at 40,000 ft?

Answer 3

• The pO2 at 40,000 ft is around 29 mmHg
• Therefore the alveolar air would be even lower d/t water vapor dilution (18 mmHg)
• At this point, the PaO2 would actually be higher than PAO2, leading to reverse gas exchange (O2 moving from Pa to alveoli) and rapid loss of conciousness

Question 4

What is CO2 classified as?

Answer 4

Volatile weak acid

Question 5

What is H2CO3 classified as?

Answer 5

Weak acid

Question 6

What is a conjugate base?

Answer 6

Base formed when an acid dissociates
HA ⇆ H+ + A-

Question 7

What makes an acid strong?

Answer 7

Dissociates (loses protons) in a aqueous solution readily

Question 8

What type of base is generated from a strong acid dissociating (HCl)?

Answer 8

Weak conjugate base (Cl- does not readily accept protons)

Question 9

What type of base is generated from a weak acid dissociating (H2CO3)?

Answer 9

Production of a strong conjugate base (HCO3- readily accepts protons)

Question 10

Ratio of CO2 to carbonic acid?

Answer 10

1000:1

Question 11

Why can we use CO2 levels to estimate acid levels; H2CO3 (HA)?

Answer 11

• CO2 rapidly forms H2CO3 whenever it is in solution and they are in equalibrium
• Because CO2 is easier to measure, we use it instead of H2CO3

Question 12

What are the non-volatile acids formed within the body?

Answer 12

• Phosphoric acid
• HCl
• Sulfuric acid
• Lactate

Question 13

How are the non-volatiles acids regulated by the body?

Answer 13

Broken down by kidney and/or liver

Question 14

Where do a lot of the non-volatile acids originate?

Answer 14

Byproduct of dietary protein metabolism

Question 15

What acids are produced in diabetics with poor control?

Answer 15

• Acetoacetic acid - sweet smelling
• Butyric acid

Question 16

What abnormal acid is formed by alcohol intake?

Answer 16

Acetoacetic acid

Question 17

Examples of weak and strong bases?

Answer 17

Weak base: Sodium fluroide (toothpaste)
Strong base: NaOH (drain cleaner)

Question 18

Explain the relationship between H+ and proteins?
Example?

Answer 18

• Proteins are made up of amino acids, some of which are negatively charged
• These negative charges bind with H+ and maintain the proteins shape and therefore function
• When H+ is in excess, more will bind with the amino acids, changing the shape and altering the function
• This happens with Hb (protein) when HbO2 is in a high H+ environment, it releases the O2 molecule

Question 19

What is it called when HbO2 releases its O2 molecule in acidic (high H+) environments?

Answer 19

Bohr effect

Question 20

How is the Na+/K+ ATPase affected by acidity?

Answer 20

• At an acidic pH, H+ can bind to the amino acids that make up the pump
• This causes the pump to slow down and not work as effectively
• This prevents K+ from being pulled into the cell resulting in hyperkalemia (this why hyperkalemia coincides with acidosis)

Question 21

How can ATP production be affected by acidosis?
How does this affect K+ levels?

Answer 21

• ATPase will be bound with H+, decreasing ATP production
• Without ATP, the Na+/K+ pump cannot function, worsening the hyperkalemia

Question 22

What is often combined with oral medications to improve their dissociation in the body?

Answer 22

HCl salt

Question 23

Why do you have to push pentobarbital slowly?

Answer 23

Its extremely basic and can damage the vessels

Question 24

pH formula based on H+ ion levels?

Answer 24

pH = -log[H+]

Question 25

What is the pH of gatric acid normally?

Answer 25

1

Question 26

What is the most alkaline secretion in the body? Why?

Answer 26

Pancreatic secretions are at a pH of 8 Attempts to neutralize the acid coming out of the stomach

Question 27

Why are the pancreatic secretions released at a higher flow than the stomach acid?

Answer 27

- The stomach acid has a pH of 1 and the pancratic secretinos have a pH of 8 - 8 is alkaline, but only just - meaning it takes a lot of it to neutralize the extremely acidic stomach secretions

Question 28

Effects on pH from high gastric motiliity and vomiting?

Answer 28

* Increased GI motility = loss of lots of pancreatic secretions (bicarb) = metabolic acidosis * Vomiting = loss of stomach acid = metabolic alkalosis

Question 29

How could you calculate the [H+] based upon the pH without a calculator?

Answer 29

[H+] = -log₁₀ → 1✖️10^-pH Example: pH of 1 = 1✖️10^-1= 0.1 mmol/L

Question 30

What is the [H+] at a pH of 7?

Answer 30

1✖️10^-7 = .0000001 = **100 nanomols/L**

Question 31

Survivable limits of pH?

Answer 31

6.90-7.80

Question 32

Relationship between pH and [H+]? Examples?

Answer 32

Since pH is logarithmic, for every change of 1 in pH, there is a change in a factor of 100 in [H+] Example: pH 6 = 1000 nmol/L, pH 7 = 100 nmol/L, pH 8 = 10 nmol/L

Question 33

What are the 3 main buffers in the body?

Answer 33

1. HCO3-, main ECF buffer 2. Proteins, Hb 3. Phosphate, main ICF buffer

Question 34

What are the buffering systems dependent on?

Answer 34

* CO2 buffering by the lungs and adequate Hb levels * If the lungs can't manage CO2 expulsion, the other buffering systems will be less effectve because CO2 is the primary determinant of physiologic pH

Question 35

How is Hb level important to pH?

Answer 35

* The more Hb in the blood, the better buffering capacity of the blood * If Hb is low, the other buffering systems dont work as well. * This is evident that at higher Hb levels, more HCO3- is in the blood at lower pH's (better buffering) | The steeper the slope, the better the buffering capacity

Question 36

At a normal pH, how much HCO3- is in the blood?

Answer 36

24 mmol/L (mEq/L)

Question 37

Explain H+ and bicarb concentrations as pH increases?

Answer 37

As pH increases, HCO3- increases and H+ decreases Could be thought of as low H+ allows more HCO3- or vice versa

Question 38

What is the relationship between pCO2 and HCO3- levels?

Answer 38

They are directly related because of the HCO3- buffering equation When pCO2 is high, HCO3- is not high enough to correct the pH - only slightly elevated ## Footnote See Increased pCO2 isobar correlates with higher HCO3-

Question 39

What is kyphoscoliosis?

Answer 39

Abnormal curvature of the spine in the sagittal and coronal plane