Respiration During Exercise Part 2 W7

Question 1

What are the 3 phases that the ventilatory response to constant load steady-sate exercise occurs?

Answer 1

Phase 1: Immediate increase in VE

Phase 2: Exponential increase in VE

Phase 3: Plaetau

Question 2

What is hyperpnoea?

Answer 2

Defined as PaCO2 regulation due to proportional changes in alveolar ventilation (VA) and metabolic rate (VCO2)

Question 3

What is the ventilatory threshold (Tvent)?

Answer 3

50-75% peak workload (VO2peak)
Lactate/anaerobic threshold

Question 4

What is ventilation relationship with exercise intensity/workload?

Answer 4

Linear Increase

Question 5

What is hyperventilation?

Answer 5

Decrease PaCO2

Question 6

What is PaCO2?

Answer 6

Partial pressure of carbon dioxide

Question 7

What happens to ventilation after reaching the ventilatory threshold?

Answer 7

It increases exponentially= hyperventilation

Question 7

What is EIAH?

Answer 7

Exercise-induced arterial hypoxaemia

Question 8

What is EIAH defined?

Answer 8

A reduction in Pa02 of >10mmHg from rest

Question 9

What individuals experience EIAH?

Answer 9

Highly trained males during heavy exercise (50%)

Majority of females regardless of fitness or exercise intensity

Question 10

What are the causes of exercise-induced arterial hypoxaemia?

Answer 10

1) Diffusion Limitation
2) V/Q mismatch
3) Relative hypoventilation

Question 11

What is VT?

Answer 11

Tidal Volume

Question 12

At the onset of exercise, how are changes in VE largely achieved?

Answer 12

Increasing tidal volume

Question 13

What percentage does tidal volume not exceed vital capacity?

Answer 13

60%

Question 14

What factors are well maintained when looking at breathing patterns until heavy exercise?

Answer 14

Arterial PO2, PCO2 and pH

Question 15

What happens to VT and VE during heavy exercise?

Answer 15

VT= Plateaus

VE= Further increases due to increased feedback

Question 15

How do we work out work in breathing?

Answer 15

Work=Pressure x Volume

Question 16

What is work within breathing?

Answer 16

The sum of elastic, flow-resistive and inertial forces

Question 17

What values can respiratory muscle work exceed?

Answer 17

500J/min
500mL O2/min

Question 18

What is Oesophageal Pressure?

Answer 18

An estimate of pleural pressure and can be used to calculate the mechanical work of breathing during exercise

Question 19

What is Poes?

Answer 19

Oesophageal pressure

Question 20

What are the 3 main group of neurons?

Answer 20

Ventral respiratory group (inspiratory and expiratory)

Dorsal respiratory group (inspiratory)

Pontine respiratory group (modulatory)

Question 21

What is the central controller of ventilation?

Answer 21

Brain stem (medulla and pons)

Question 22

What are the motor outputs of control of ventilation?

Answer 22

Resistance muscles (cricoarytenoid)

Pump muscles (diaphragm)

Question 23

What are the feedback inputs of the control of ventilation?

Answer 23

Peripheral/Central Chemoreceptors Muscle afferents (peripheral neurogenic) VO2 flow (peripheral neurogenic)

Question 24

Where are peripheral chemoreceptors located?

Answer 24

The aortic arch and carotid body

Question 25

What do peripheral chemoreceptors do?

Answer 25

Detect changes in PO2 of blood perfusing systemic and cerebral circulation

Question 26

What does a decrease in PaO2 result in?

Answer 26

Increase in VE

Question 27

What stimuli activate peripheral chemoreceptors?

Answer 27

Temperature Adrenaline CO2 Changes to PaO2 and VE

Question 28

Where does peripheral chemoreceptors relay sensory information to?

Answer 28

Medulla (NTS) via vagus (CN X) and glossopharyngeal (CN IX) nerves

Question 29

What are central chemoreceptors?

Answer 29

PCO2 sensors

Question 30

What are peripheral chemoreceptors?

Answer 30

PO2 sensors

Question 31

Where are central chemoreceptors located?

Answer 31

Primarily in the ventral surface of the medulla= retrotrapezoid nucleus

Question 32

What is RTN?

Answer 32

Retrotrapezoid nucleus

Question 33

What does an increase in PaCO2 result in?

Answer 33

Increase in VE

Question 34

What is RTN sensitive too?

Answer 34

Changes in PaCO2 and H+

Question 35

What is the ventilatory response like to O2?

Answer 35

Curvilinear

Question 36

What is the ventilatory response to CO2 like?

Answer 36

Linear

Question 37

What are the chronic training adaptions to endurance training which improves aerobic capacity?

Answer 37

Decreased metabolite accumulation Decreased afferent feedback Decreased ventilatory drive

Question 38

What is the difference of VE between trained and untrained individuals during submaximal exercise?

Answer 38

20-30% lower in trained individuals

Question 39

What are the respiratory structural adaptations to training?

Answer 39

NONE

Question 40

What fine tunes exercise during moderate-intensity exercise?

Answer 40

Peripheral chemoreceptors

Question 41

What are the respiratory functional adaptations to training?

Answer 41

Increased: Ve/VO2 Respiratory muscle strength Respiratory muscle endurance

Question 42

How may the pulmonary system limit exercise performance? (5)

Answer 42

1) Exercise-induced arterial hypoxaemia (EIAH) 2) Exercise-induced laryngeal obstruction (EILO) 3) Expiratory flow limitation 4) Respiratory muscle fatigue 5) Intrathoracic pressure effects on cardiac output