Pulmonary System & Exercise

Question 1

Functions of the pulmonary system

Answer 1

• supply oxygen required in metabolism
• eliminate carbon dioxide produced in metabolism
• regulate hydrogen (H+) to maintain acid-base balance (pH)

Question 2

How does inspiration work

Answer 2

• diaphragm contracts, flatness out, and moves downward
• the lungs expand along with the thoracic cage causing the pressure to lower
• the lower pressure in the lungs then suck air in through the nose and mouth to inflate the lungs

Question 3

How does expiration work

Answer 3

• the recoil from the lungs being stretched and the diaphragm relaxing pushes air out of the lungs
• the sternum and ribs swing down decreasing chest cavity volume

Question 4

Define tidal volume (TV)

Answer 4

• volume inspired or expired per breath
• 0.4-1.0 L

Question 5

Define inspiratory reserve volume (IRV)

Answer 5

• maximum inspiration at end of tidal inspiration (forced inhale)
• 2.5-3.5 L above TV

Question 6

Define expiratory reserve volume (ERV)

Answer 6

• the additional volume that can be exhaled after a normal exhalation
• 1.0-1.5 L for men and 10-20% lower for women

Question 7

Define forced vital capacity (FCV)

Answer 7

• maximum volume expired after maximum inspiration

Question 8

Define residual lung volume (RLV)

Answer 8

• volume of air that remains after maximal exhalation that cannot be exhaled
• 1.2-1.6 L for men and 1.0-1.2 L for women

Question 9

Equation for minute ventilation

Answer 9

Minute Ventilation Ve = breathing rate x tidal volume

Question 10

Define anatomic dead space

Answer 10

the air that fills the nose, mouth, trachea, and other nondiffusible conducting portions of the respiratory tract

Question 11

Define physiologic dead space

Answer 11

the portion of the alveolar volume with poor tissue regional perfusion or inadequate ventilation

Question 12

Define dyspnea

Answer 12

shortness of breath or subjective distress in breathing

Question 13

Define hyperventilation

Answer 13

an increase in pulmonary ventilation that exceeds the oxygen needs of metabolism

Question 14

Define gas concentration

Answer 14

the amount of gas in a given volume determined by the product of the gas’ partial pressure and solubility

Question 15

Define gas pressure

Answer 15

the force exerted by the gas molecules against the surfaces they encounter

Question 16

Define partial pressure

Answer 16

percentage concentration x total pressure of gas mixture

Question 17

Define Henry’s law

Answer 17

The amount of a gas dissolved in fluid depends on:
- pressure differential between the gas above the build and dissolved in it
- solubility of the gas in the fluid

Question 18

Neural factors for ventilatory control during rest

Answer 18

• temperature
• receptors in lung tissue
• proprioceptors in joints & muscles
• chemical state of blood in medulla
• peripheral chemoreceptors
• motor cortex
• subcortical regions

Question 19

Define chemoreceptors

Answer 19

• structures that stimulate ventilation in response to increased carbon dioxide, temperature, and acidity, a decrease in oxygen & blood pressure, and perhaps a decline in circulating potassium

Question 20

Chemical factors of ventilatory control during exercise

Answer 20

• Po2
• Pco2
• H+

Question 21

Peripheral influence on ventilatory control during exercise

Answer 21

• sensory input from joints, tendons, and muscles adjust ventilation during exercise

Question 22

Cortical influence on ventilatory control during exercise

Answer 22

• neural outflow from regions of the motor cortex during exercise and cortical activation in anticipation of exercise stimulate respiratory neurons in the medulla

Question 23

Phase I Ventilation

Answer 23

• neurogenic stimuli from the cerebral cortex & active limbs cause the initial, abrupt increase in breathing when exercise begins

Question 24

Phase II Ventilation

Answer 24

• central command input plus medullary control system neurons & peripheral stimuli from chemoreceptors & mechanoreceptors contribute to the control of minute ventilation gradually increasing to a steady level

Question 25

Phase III Ventilation

Answer 25

• “fine tuning” of ventilation through peripheral sensory feedback mechanism

Question 26

What is ventilatory equivalent for oxygen (Ve/VO2)

Answer 26

• ratio of minute ventilation to oxygen uptake
• it remains relatively constant during steady-rate exercise

Question 27

What is ventilatory equivalent for carbon dioxide (Ve/VCO2)

Answer 27

• ratio of minute ventilation to oxygen produced
• it remains constant during steady-rate exercise bc pulmonary ventilation eliminates the CO2 produced during cellular respiration

Question 28

What is ventilatory threshold

Answer 28

• the point at which pulmonary ventilation increases disproportionately with oxygen uptake during graded exercise
• relates directly to CO2 increased output from the buffering of lactate that begins to accumulate from anaerobic metabolism

Question 29

Describe OBLA (onset of blood lactate accumulation)

Answer 29

• is 4 mMol/L in everyone
• occurs between 55-65% of VO2 max in healthy untrained individuals and closer to 80% VO2 max in highly trained endurance athletes

Question 30

Define lactate threshold

Answer 30

• it’s the point of intensity when lactate production exceeds lactate removal

Question 31

What factors determine the energy requirements of breathing

Answer 31

• compliance of lungs & thorax
• resistance of airways to the smooth flow of air
• breathing normally requires a relatively small oxygen cost even during exercise