pH Acid-Base Disorders

Question 1

Why is pH homeostasis important?

Answer 1

The body’s proteins change their conformation and structure irreversibly (denature) with changes in pH and are unable to function normally

Question 2

If Enzymes have a 0.1-unit change it may reduce activity by?

Answer 2

90%

Question 3

If A active transport proteins (eg.Na+/K+ pump undergo a 1.0-unit change this will reduce function by?

Answer 3

50%

Question 4

Acids?

Answer 4

Donates free H+ ions when dissolved in water

Question 5

Bases?

Answer 5

Accepts free H+ ions when dissolved in water

Question 6

Blood pH is ?

Answer 6

7.35 –7.45 is normal (slightly alkali)

Question 7

Outside of pH 6.8 –7.7 get?

Answer 7

Cell death

Question 8

Normal body metabolism produces an excess of ______

Answer 8

Acids

Question 9

Acids produced by metabolism include?

Answer 9

Carbonic acid from CO2 – aerobic respiration
Lactic acid –from anaerobic respiration
Ketones
Sulfuric acid
Phosphoric acid

Question 10

The 2 types of pH regulators or Buffers?

Answer 10

1. Chemical buffers - immediate response
2. Physiological - Respiratory & renal -take more take but more powerful

Question 11

Buffers react with a relatively strong acid (or base) to replace it a?

Answer 11

Weak acid or base

Question 12

Buffers types?

Answer 12

Types – proteins, hemoglobin, phosphate buffer systems and bicarbonate-carbonic acid system

Question 13

How do buffers work?

Answer 13

Work by absorbing or releasing acid (H+) as required to maintain normal blood pH

Question 14

Bicarbonate-carbonic acid buffer system is the most____

Answer 14

Powerful buffer

Question 15

To maintain a pH of 7.35-7.45, a proportion of 20 bicarbonate ions (HCO 3 ) to____

Answer 15

A carbonic acid

Question 16

Respiratory and renal systems are physiological buffering systems used when?

Answer 16

Chemical buffer system cannot control pH homeostasis, slower but have more buffering power long-term

Question 17

During CO2 unloading (at lungs), the reaction shifts to?

Answer 17

Left (alkali) as H+ released

Question 18

During CO2 loading (at tissue), the reaction shifts to?

Answer 18

Right (acidosis) as (H+ is buffered)

Question 19

CO2 production must equal CO2?

Answer 19

Excretion

Question 20

Ventilation is sensitive to?

Answer 20

CO2, H+, O2 levels

Question 21

If PCO2 in blood rises what does the RS do?

Answer 21

Increased respiratory rate and depth which releases H+

Question 22

How Respiratory system impairment causes acid-base imbalances?

Answer 22

1. Hypoventilation = acidosis
2. Hyperventilation = alkalisis

Question 23

Kidneys are most effective in compensating an acid base imbalance because?

Answer 23

Because they can excrete H+ and bicarbonate into urine to be completely removed

Question 24

Lungs regulate ___ levels

Answer 24

CO2

Question 25

Kidneys regulate ______and _____ levels

Answer 25

Biocarbonate and H+

Question 26

ROME" mnemonic: Respiratory Opposite, Metabolic Equal, meaning?

Answer 26

In respiratory disorders, the pH and PaCO2 move in opposite directions In metabolic disorders, pH and bicarbonate (HCO3-) move in the same direction

Question 27

In uncompensated respiratory acidosis, what is high?

Answer 27

low pH, high CO2, biocarbonate normal

Question 28

Causes of R Acidosis?

Answer 28

Will occur with hypoventilation:  Asthma  Asbestosis  COPD & narcotic overdose  Lung cancer & pulmonary oedema  Pneumonia & respiratory distress syndrome  Damage to resp. muscles (RDS) in newborns

Question 29

What happens in Uncompenated Metabolic (non resp) Acidosis?

Answer 29

Low pH Low CHO3 (< 22 mmol/L) CO2 normal

Question 30

M Acidosis occur with?

Answer 30

 Severe diarrhea - (loss of bicarbonate from gut)  Renal disease - (disorder in removing hydrogen ions from body, hydrogen ion levels raise, buffered by bicarbonate but buffer capacity is limited)  Untreated diabetes mellitus or starvation - (production of ketone bodies (acetoacetic acid, beta-hydroxybutyric acid) causing diabetic ketoacidosis

Question 31

In uncompensated respiratory alkalosis?

Answer 31

pH high, CO2 low, CHO3 normal

Question 32

Causes of uncompensated respiratory alkalosis?

Answer 32

Hyperventilation  hypoxemia causing hyperventilation  Strong emotions  Brain tumor injury affecting respiratory controls

Question 33

In uncompensated metabolic alkalosis?

Answer 33

pH high, CHO3 high and CO2 normal

Question 34

Metabolic Alkalosis occurs due to?

Answer 34

 Vomiting or gastric suctioning (loss of acid)  Some diuretics that cause loss of potassium and hydrogen ions at kidney * Overdose of antacids  Adrenal tumors that result in over secretion of the hormone aldosterone, which results in secretion of hydrogen ions at kidney

Question 35

If compensation is occurring can be identified because?

Answer 35

It opposes the observed deviation in blood pH

Question 36

What happens during compensation of respiratory acidosis?

Answer 36

Compensated respiratory acidosis will show a normal pH or acidic pH, but an elevated PCO2 (>45mm Hg) and elevated HCO3

Question 37

What happens during compensation of respiratory alkalosis?

Answer 37

Lower-than-normal PCO2 & Bicarbonate

Question 38

What happens during compensation of metabolic acidosis ?

Answer 38

Low HCO3 (< 22 mmol) PCO2 below normal (< 35 mmol) as lungs blow off Co2

Question 39

What happens during compensation of metabolic alkalosis

Answer 39

High HCO3 (> 29) High CO2 (> 45) as lungs retain CO2

Question 40

The ‘arterial blood gas (ABG) test measures?

Answer 40

 pH  Carbon dioxide (PCO2)  Bicarbonate (HCO3-)  Oxygen (PO2)  % saturation (O2)

Question 41

What are the 4 steps of Interpretation of ABG test?

Answer 41

1. Note the pH 2. Check the PCO2 a) PCO2 >45mmHg and pH 7.45 (alkalosis), then resp. system is the cause (namely: respiratory alkalosis) b) PCO2 is in normal range, the respiratory system is not responsible for the imbalance, the cause is metabolic 3. Check the bicarbonate (HCO3-) level