Lecture 6

Question 1

How does bicarbonate buffer protons?

Answer 1

Bicarbonate + Proton -> Water + Carbon dioxide

HCO3 + H+ <–> H2O + CO2

-Carbonic anhydrase is the enzyme

Question 2

Hyperpnea vs Hyperventilation

Answer 2

Hyperpnea: Ventilation increase proportional to metabolic demands (blood gases are normal)
Hyperventilation: Ventilation exceeds metabolic demands (Blood CO2 increases disproportionately to blood O2)

Question 3

What receptor signals increased ventilation during severe-intensity exercise?

Answer 3

The arterial chemoreflex receptor
(in the carotid artery)
-Senses elevated proton levels
-Signals increased ventilation

Question 4

Respiratory compensation point (RCP)

Answer 4

The point at which heavy turns to severe intensity, hyperventilation ensues

Question 5

Two metabolic thresholds

Answer 5

GET/VT1:
-Same as lactate threshold
-Separates moderate from heavy
RCP/VT2:
-Same as critical intensity
-Separates heavy from severe
-Bicarbonate can’t prevent acidosis
from lactate production
-Hyperventilation ensues

Question 6

Why would an RER turnpoint be present in the data?

Answer 6

If hyperventilation ensues prior/at the beginning of the test
-Would cause early changes in VCO2 and VO2
(not reflective of lactate production)