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
3 Phases of respiratory response to sub-max exercise:
- Rapid Increase
- Slower exponential rise
- Fine tuning of ventilation
The Ventilatory drifting occurs in order to:
Maintain the intensity of exercse
An increase in respiratory depth, then what are typically the first two mechanism to increase pulmonary ventilation
In depth and rate are the first two mechanisms
