Ch14 Pt1 Flashcards
Ventilatory Control happens because of
The autonomic system (involuntary)
Respiratory center in the medulla (brain stem)
Integrated Control responds to:
A variety of input from the body to regulate ventilation rate
-in response to metabolic need
Integrated Regulation
No single factors controls exercise response
-is a combination of chemical and neural stimuli
Chemical Stimuli
PCO2 and H+
-provide most important respiratory response -indicates decrease in pH
Neural Stimuli
Cortical and peripheral influence
-in anticipation of exercise
-signals increase in exercise ventilation
3 Phases of Respiratory Response to Exercise
- Neurogenic, central command in cerebral cortex (rapid increase)
- Slower exponential rise to reach steady-state (20s after initiation)
- Fine tuning of steady state ventilation
Ventilatory responses to exercise: Values increase, decrease?
Oxygen consumption increases
Minute Ventilation increases
Tidal volume increases, then plateaus at 60% of VC
Respiratory Rate increases
Ventilation increases how with O2 consumption and CO2 production
Linearly
VE/ VO2
-25L up to 100L -around 55%
Ventilatory Threshold
Exponential increase in Ventilation
Lactate Threshold
Exponential increase in lactate accumulation
OBLA
Onset of Blood Lactate Accumulation
-point where lactate increases above 4.0 mM
Ventilatory Equivalent
VE/VO2
-ratio of minute ventilation to O2 consumption
VA (alveolar) rises to maintain?
PO2 at the alveolar level (PAO2)
-represents driving force of oxygen transfer from alveoli into blood stream
A-a PO2
Alveolar to arterial oxygen partial pressure difference
-reflects efficiency of oxygen transfer in lungs during exercise
Ventilatory Drift
Around 30 mins exercise there is a gradual rise in VE (minute ventilation)
-due to increase in body temp (poss)
Advantageous because VAO2 parallels drift and acid base balance is maintained
