S6 L1 Acid-Base Balance

Question 1

Plasma pH range
A change in one pH unit represents a _____ change in H+ concentration
pH of the urine varies between…

Answer 1

• Plasma pH must be maintained within a tight range
• pH 7.35 – 7.45
• A change in one pH unit represents a 10-fold change in H+ concentration.
• Extracellular pH usually reflect intracellular pH and visa versa
• pH of the urine varies between 4.5 and 8.5 depending on the bodies need to excrete H+ or HCO3-

Question 2

Alkalaemia

• How does alkalemia effects Ca2+
• What symptoms does this lead to?
• Which pH, which symptoms?

Answer 2

Question 3

Acidemia:

• How does alkalemia effects Ca2+
• What symptoms does this lead to?
• Which pH, which symptoms?

Answer 3

Question 4

Sources of Acids and Bases:

• Sources of input
• Sources of output

Answer 4

Question 5

pH homeostasis

• Three mechanisms to control pH of the blood
• 2 ways kidney’s alter pH

Answer 5

Question 6

Mechanisms of buffering in the PCT
- 3 main ones

Answer 6

• HCO_3^-
• Phosphate
• Ammonia

Question 7

Late DCT/CD:

• What happens in acidosis?
• What happens in alkalosis?
• How does acidosis and alkolosis effect serum potassium

Answer 7

Question 8

How does aciodisis lead to hyperkalaemia?
How can hyperkalaemia lead to acidosis?

How does alkalosis lead to hypokalaemia?
How can hypokalaemia lead to alkalosis?

Answer 8

Question 9

Respiratory Acidosis:

• Occurs when…
• How does the body resolve this (mechanism)…

Answer 9

Question 10

Respiratory Alkalosis:
- Occurs when…
​- How does the body resolve this (mechanism)…

Answer 10

Question 11

Metabolic Acidosis:

• Occurs when…
• How does the body resolve this (mechanism)…

Answer 11

Question 12

Anion Gap:

• What is this? What does it tell the difference between…
• How to work this out?
• Explain the difference between the two things it differentiates between

Answer 12

Work out if: Metabolic cause or Renal cause

Question 13

ABG:
- pH 7.12
- pO2 19.6kPa (8-
12)
- pCO2 2.6kPa (4-6)
- HCO3-:10mmol/l (22-28)

What sort of acid-base disturbance is present?
What is the anion gap?

Answer 13

Metabolic acidosis

Anion gap - suggests a metabolic cause, for example, diabetic ketoacidosis, lactic acidosis

Question 14

Metabolic Alkalosis:
- Occurs when…
​- How does the body resolve this (mechanism)…

Answer 14

Question 15

Summary of Acid/Base Disturbances:
- Fill in the table

Answer 15

Question 16

What are the causes of hupokalaemia?

Answer 16

• Renal losses: diuretics, renal tubular acidosis, excess aldosterone
• GI losses
• Alkalosis: hydrogen ions transported out of cells at the expense of K+

Question 17

What is renal tubular acidosis?
- Cause of it?

Answer 17

• Renal tubular acidosis: when the kidneys do not remove acids from the blood into the urine as they should. There are different types of RTA
• Can be caused by drugs, or born with it

Question 18

GW:
- Look at GW for examples of this