Week 10

Question 1

List the percentage of gas concentrations in ambient air at sea level

Answer 1

• Oxygen = 20.93%
  
  • Carbon dioxide = 0.03%
  • Nitrogen: 79.04%

Question 2

Why does the effective PO2 in tracheal air decrease about 10 mmHg from its ambient value of 159 mmHg to 149 mmHg?

Answer 2

• Saturated with water vapor passing through the nose and mouth. Water vapor dilutes air mixtures

Question 3

According to William henry, what factors influence the rate of gas diffusion into a fluid

Answer 3

• 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

Question 4

Name two factors that impair gas transfer capacity at the alveolar capillary membrane

Answer 4

• Buildup of a pollutant layer that thickens the alveolar membrane
  
  • Reduction in alveolar surface area

Question 5

What is the Bohr effect?

Answer 5

• Any increase in plasma acidity and temperature causing the oxyhemoglobin dissociation curve to sift downward and to the right

Question 6

Explain mechanics of ventilation for inspiration and expiration

Answer 6

Inspiration

- Diaphragm descends 
- Ribs rise 

Expiration

- Diaphragm moves up 
- Ribs lower

Question 7

Intensity and duration of inspiration is driven by what?

Answer 7

The neural center in the hypothalamus

Question 8

Fill in the blanks

Peripheral chemoreceptors defend against ………… in pulmonary disease and ascent to higher altitudes and help to regulate …………..

Answer 8

Arterial hypoxia

Exercise hypernea

Question 9

Two important breathing stimuli?

Answer 9

Increase in CO2

Decrease in pH

Question 10

Is Pco2 an important respiratory stimulus?

Answer 10

Yes

Question 11

Explain Feed Forward control of ventilation during exercise

Answer 11

• Neural outflow from regions of the motor cortex stimulate respiratory neurons in the medulla to initiate the abrupt increase in exercise ventilation

Question 12

Explain feedback control of ventilation during exercise

Answer 12

• Sensory input from joints, tendons and muscle influences the ventilatory adjustments throughout exercise

Question 13

Define La threshold

Answer 13

• Highest Vo2 or exercise intensity achieved with <1mM increase in La above rest

Question 14

Define OBLA

Answer 14

Signifies increase in La to 4mM

Question 15

4 factors African runners possess

Answer 15

1. Increased oxidative enzymes profile
   
   2. Decreased plasma La-
   3. Increased running economy
   4. Decreased heat storage due to smaller stature

Question 16

both VO2 max and OBLA predict what

Answer 16

Performance

Question 17

For endurance athletes, what system lags behind cardiovascular and aerobic adaptations

Answer 17

Pulmonary system

Question 18

3 main buffers

Answer 18

• Chemical
  
  • Pulmonary function
  • Renal function

Question 19

Explain chemical buffers and the 3 types

Answer 19

• Consist of a weak acid and salt of that acid

Chemical buffers include bicarbonate, phosphate and proteins

Question 20

What are the two most important chemical regulatory factors

Answer 20

Arterial Pco2

H+