6.1 Acid-base balance renal control

Question 1

Normal values of following:
1. pH
2. pCO2
3. [HCO3-]
4. pO2

Answer 1

1. 7.35 - 7.45
2. 4 - 6
3. 19-24
4. 10.6 - 14.5

Question 2

pH value when acidemia ? what does it reflect ?

Answer 2

serum pH < 7.35. Reflects an increase in [H+] or a decrease in [HCO3-] in the blood

Question 3

pH value when alkalemia ? what does it reflect ?

Answer 3

serum pH > 7.45. Reflects a decrease in [H+] or an increase in [HCO3-].

Question 4

Acidosis refers to physiologic processes that cause ….

Answer 4

acid accumulation or alkali loss (drop
in pH)

Question 5

Alkalosis refers to physiologic processes that cause …

Answer 5

alkali accumulation or acid loss (raising of pH)

Question 6

What is a buffer ?

Answer 6

a solution that resists changes in pH when a small amount of acid or base is added

Question 7

what does a buffer solution consist of ?

Answer 7

a weak acid and its conjugate base or a weak base and its conjugate acid

Question 8

What must be constantly maintained in order to maintain a normal pH of 7.4 in the blood ?

Answer 8

a 20:1 ratio of bicarbonate to carbonic acid

Question 9

How do changes in pCO2 or [HCO3-] affect pH ?

Answer 9

If ratio of [HCO3-] to pCO2 stays constant then the pH will also stay constant
If [HCO3-]: pCO2 INC then pH will INC
If [HCO3-]: pCO2 DEC then pH will DEC

Question 10

Respiratory acidosis:
1. cause
2. effect
3. ratio impact

Answer 10

1. Hypoventilation (e.g., COPD, respiratory depression from drugs).
2. Increased pCO2 (hypercapnia) due to inadequate exhalation of CO2.
3. Decreased [HCO3 −] : pCO2 ratio, leading to a decrease in pH (acidaemia).

Question 11

Respiratory alkalosis:
1. cause
2. effect
3. ratio impact

Answer 11

1. Hyperventilation (e.g., anxiety, high altitude).
2. Decreased pCO2 (hypocapnia) due to excessive exhalation of CO2.
3. Increased [HCO3 −] : pCO2 ratio, leading to an increase in pH (alkalaemia).

Question 12

metabolic acidosis :
1. cause
2. effect
3. ratio impact

Answer 12

1. Loss of bicarbonate (e.g., diarrhea, renal tubular acidosis) or accumulation of acid (e.g., diabetic ketoacidosis, lactic acidosis).
2. Decreased [HCO3 −] due to bicarbonate buffering the excess acid.
3. Decreased [HCO3 −] : pCO2 ratio, leading to a decrease in pH. Respiratory compensation may occur (hyperventilation to lower pCO2 ).

Question 13

metabolic alkalosis:
1. cause
2. effect
3. ratio impact

Answer 13

1. Cause: Excess bicarbonate (e.g., vomiting, diuretic use) or loss of hydrogen ions.
2. Increased [HCO3 −]
3. Increased [HCO3 −] : pCO2 ratio, leading to an increase in pH. Respiratory compensation may occur (hypoventilation to raise pCO2 ).