Week 12: Acid-Base Physiology (Ben)

Question 1

What is the pH of cytosol?

Answer 1

7.2

Question 2

What is the main membrane transporter that is activated by decreased intracellular pH?

Answer 2

Na⁺/H⁺ Exchanger/Antiporter

Question 3

What is the main membrane transporter activated by increased intracellular pH?

Answer 3

Bicarbonate/Chloride Exchanger

• removes bicarbonate which is essentially the same as “adding” H⁺

Question 4

What are the important buffers of intracellular fluid?

Answer 4

• Protein Buffers (especially hemoglobin)
• Bicarbonate
• (less important: mono/dibasic phosphate)

Question 5

What are the important buffers of plasma?

Answer 5

• Bicarbonate
• Plasma Proteins
• (mono/dibasic phosphate)

Question 6

What are the important buffers of interstitial fluid?

Answer 6

• bicarbonate
• (interstitial protein buffers)

Question 7

What is the only important buffer in CSF?

Answer 7

bicarbonate

Question 8

What are the important buffers in the urinary tract?

Answer 8

• Phosphate
• Creatinine
• Uric Acid
• (Ammonium)

Question 9

What is the pK of the bicarbonate buffer?

Answer 9

6.1

Question 10

What is the pK of the phosphate buffer?

Answer 10

6.8

Question 11

What is the pK of the ammonium buffer?

Answer 11

~9

Question 12

Why is bicarbonate a more important blood buffer, even though phosphate’s pK is closer to blood pH?

Answer 12

Because there is a higher concentration of bicarbonate in the blod