Chapter 9: Pulmonary System and Physical Activity

Question 1

3 major functions of ventilatory system

Answer 1

1. Supply oxygen required in metabolism
2. eliminate carbon dioxide produced in metabolism
3. regulate hydrogen ion concentration to maintain acid-base balance

Question 1

Mechanics of Ventilation: Inspiration

Answer 1

Diaphragm contracts, flattens out, moves downward. Air in lungs expands, reducing its pressure.

Question 2

Mechanics of Ventilation: Expiration

Answer 2

Predominantly passive process, air moves out of lungs from recoil of stretched lung tissue and relaxation of inspiratory muscles

Question 3

Tidal Volume (TV)

Answer 3

Air moved during inspiratory or expiratory phase of breathing cycle; between 0.4 to 1.0 L of air per breath

Question 4

Inspiratory Reserve Volume (IRV)

Answer 4

2.5 to 3.5 L above TV; serves as inhalation reserve

Question 5

Expiratory Reserve Volume (ERV)

Answer 5

After normal exhalation, additional volume exhaled; 1.0 to 1.5 L for men, 10 to 20% lower for women

Question 6

Forced Vital Capacity (FVC)

Answer 6

Total air volume moved in 1-breath from full inspiration to max expiration; varies with body size and body position when measuring

Question 7

Residual Lung Volume (RLV)

Answer 7

Following max exhalation,
air volume that cannot be exhaled; 1.2 to 1.6 L for men, 1.0 to 1.2 L for women

Question 8

Dynamic measures of pulmonary ventilation

Answer 8

1. max air volume expired (FVC)
2. Speed of moving a volume of air

Question 9

Physiological Dead Space

Answer 9

Portion of alveolar volume with poor tissue
regional perfusion or inadequate ventilation

Question 10

Henry’s Law

Answer 10

Amount of gas dissolved in fluid depends on:
– Pressure differential between gas above fluid and
dissolved in it
– Solubility of gas in fluid

Question 11

Blood transports oxygen in two ways

Answer 11

1. Physical solution
2. combined with Hb

Question 12

Cortical Influence

Answer 12

Neural outflow from regions of motor cortex during PA and cortical activation in anticipation of PA stimulate respiratory neurons in medulla

Question 13

Peripheral Influence

Answer 13

Sensory input from joints, tendons, muscles adjust ventilation during PA

Question 14

Phase I ventilation

Answer 14

When PA begins, neurogenic stimuli from cerebral cortex and active limbs cause initial breathing increase

Question 15

Phase II ventilation

Answer 15

Central command input plus medullary control neurons and peripheral stimuli from chemoreceptors and mechanoreceptors contribute to control minute ventilation, gradually increasing to a steady level

Question 16

Phase III ventilation

Answer 16

“Fine tuning” of ventilation through peripheral sensory feedback mechanism

Question 17

Despite variations in ventilatory equivalents among health people, complete aeration of blood takes capillaries proceeds slowly enough to allow complete gas exchange
place because of 2 factors

Answer 17

1. Alveolar Po2 and Pco2 remain at near-resting value.
2. Transit time for blood flowing through pulmonary

Question 18

Tvent

Answer 18

point at which PV increases disproportionately with VO2 max during graded activity, Relates directly to increased CO2 output from buffering of lactate that begins to accumulate from anaerobic metabolism

Question 19

Onset of Blood Lactate Accumulation (OBLA)

Answer 19

Occurs between 55 to 65% VO2max in healthy, untrained subjects and often equals >80% VO2max in highly trained endurance athletes, OBLA point increases with aerobic training without accompanying increase in VO2max

Question 20

Two factors influence endurance performance

Answer 20

1. VO2 max
2. max level for steady-rate activity (OBLA)

Question 21

Two factors determine energy requirements of breathing

Answer 21

1. compliance of lungs and thorax
2. resistance of airways to smooth air flow