List the percentage of gas concentrations in ambient air at sea level
- Oxygen = 20.93%
- Carbon dioxide = 0.03%
- Nitrogen: 79.04%
Why does the effective PO2 in tracheal air decrease about 10 mmHg from its ambient value of 159 mmHg to 149 mmHg?
- Saturated with water vapor passing through the nose and mouth. Water vapor dilutes air mixtures
According to William henry, what factors influence the rate of gas diffusion into a fluid
- The pressure differentia between the gas above the fluid and the gas dissolved in the fluid and the solubility of the gas in the fluid
Name two factors that impair gas transfer capacity at the alveolar capillary membrane
- Buildup of a pollutant layer that thickens the alveolar membrane
- Reduction in alveolar surface area
What is the Bohr effect?
- Any increase in plasma acidity and temperature causing the oxyhemoglobin dissociation curve to sift downward and to the right
Explain mechanics of ventilation for inspiration and expiration
Inspiration
- Diaphragm descends - Ribs rise
Expiration
- Diaphragm moves up - Ribs lower
Intensity and duration of inspiration is driven by what?
The neural center in the hypothalamus
Fill in the blanks
Peripheral chemoreceptors defend against ………… in pulmonary disease and ascent to higher altitudes and help to regulate …………..
Arterial hypoxia
Exercise hypernea
Two important breathing stimuli?
Increase in CO2
Decrease in pH
Is Pco2 an important respiratory stimulus?
Yes
Explain Feed Forward control of ventilation during exercise
- Neural outflow from regions of the motor cortex stimulate respiratory neurons in the medulla to initiate the abrupt increase in exercise ventilation
Explain feedback control of ventilation during exercise
- Sensory input from joints, tendons and muscle influences the ventilatory adjustments throughout exercise
Define La threshold
- Highest Vo2 or exercise intensity achieved with <1mM increase in La above rest
Define OBLA
Signifies increase in La to 4mM
4 factors African runners possess
- Increased oxidative enzymes profile
- Decreased plasma La-
- Increased running economy
- Decreased heat storage due to smaller stature
both VO2 max and OBLA predict what
Performance
For endurance athletes, what system lags behind cardiovascular and aerobic adaptations
Pulmonary system
3 main buffers
- Chemical
- Pulmonary function
- Renal function
Explain chemical buffers and the 3 types
- Consist of a weak acid and salt of that acid
Chemical buffers include bicarbonate, phosphate and proteins
What are the two most important chemical regulatory factors
Arterial Pco2
H+
