IP3: Regulation of Acid/Base Balance

Question 1

What are the fixed acids excreted by the kidneys?

Answer 1

➢Protein Catabolism – sulfuric acid and HCl
➢Phospholipid Catabolism – phosphoric acid
➢Exercise, hypoxia – lactic acid
➢Post-absorptive state, diabetes mellitus –acetoacetic, β-hydroxy-butyric acids
➢Nucleoprotein metabolism – uric acid

Question 2

What are the three primary systems that regulate the acid in the body?

Answer 2

chemical
respiraotry
kidneys

Question 3

What are the two parts of the chemical system that regulates acid?

Answer 3

bicarbonate buffer syste
phosphate buffer system

Question 4

What are the features of the chemical system that regulates acid?

Answer 4

• instantaneous
• does not add or remove H+ but keeps it “tied up”
• acid-base buffer systems

Question 5

What is the most powerful EC buffer?

Answer 5

bicarbonate buffer system

Question 6

What is the phosphate buffer system used for?

Answer 6

• buffering renal tubular fluids and ICF
• not as significant as the bicarb buffer system

Question 7

How does H+ enter into the cells?

Answer 7

➢ CO2
➢ Produced: Lactic, acetoacetic, β-hydroxylbutyric acid
➢ H+/K+ exchange

Question 8

What are the features of the respiratory systems regulation of acid?

Answer 8

• regulates the removal of CO2 (and acid)
• changes VA
• seoncs to minutes (FAST)

Question 9

What are the three processes that facilitate CO2 transport?

Answer 9

• 10% dissolved in plasma
• 25% binds to amino groups in Hb
• Remainder converted to H2CO3 by CA in erythrocytes

Question 10

Changes in ______ can function to restore pH following acid/base disturbances

Answer 10

VA (alveolar ventilation)

Question 11

What are the features of the kidneys way to regulate acid?

Answer 11

• excrete an acidic or alkaline urine
• hours to days (slow)
• most powerful of the acid/base regulator system

Question 12

What is the most powerful acid/base regulatory system?

Answer 12

kidneys!

Question 13

Kidneys regulate pH by altering plasma _________

Answer 13

[HCO3-]

• secrete H+
• reabsorb, produce, or excrete HCO3-

Question 14

For each HCO3- reabsorbed, a _____ must be secreted.

Answer 14

H+

Question 15

H+ is Secreted by what type of transport?

Answer 15

Secondary Active

Question 16

What is the pattern of H+ secretion?

Answer 16

proximal tubule
thick ascending limb
early distal tubule

Question 17

In ________, H+ secretion > HCO3- load and excess H+ excreted

Answer 17

Acidosis

Question 18

In ________, HCO3- load > H+ secretion and excess HCO3- will be excreted

Answer 18

Alkalosis

Question 19

Which part of the nephron has excess H+ excretion?

Answer 19

late distal tubule
collecting duct

Question 20

What are the two most important stimuli that increase H+ secretion by tubules?

Answer 20

1. Increase in PCO2 of ECF
2. Increase [H+]ECF

Question 21

What stimuli cause an increase in H+ secretion and increase in HCO3- reabsorption?

Answer 21

Question 22

What stimuli cause a decrease in H+ secretion and decrease in HCO3- reabsorption?

Answer 22