Physiology 12.18.13 Respiratory System under Stress

Question 1

What does exercise to do respiraotry system

Answer 1

stresses resp system by INcreaseing demand for O2 and increasng production of CO2

Moderate to seere exercise also increase lactic acid production

Question 2

What is the resp and CV system response to stress

Answer 2

resp and CV must crease volume of O2 supplied to exercising tissues and inc. removal of CO2 and H+ ions from body

Question 3

Metabolic response to accute exercise

Answer 3

Increase Oxygen consumpion (VO2)

Increase CO2 production (VCO2)

Question 4

Cardiac changes to acute exercise

Answer 4

VO@ is related ot CO

CO is ml/min

Question 5

What is the systemic circulation change to acute exercise

Answer 5

Increase in CO causes more blood to be delivered to exercising muscles.

There is a redistribution of systemic circulation involving vasodilation in teh skin and working muscles

Question 6

What is the oxygen extaction changes during acute exercise

Answer 6

Apart from increased CO and vascular redistribution, third mechanism to meet O2 requirement is increased oxygen extraction from ARTERIAL BLOOD

This results in an increased arterial-venous oxygen content difference

Question 7

What are the pulmonary circulation changes

Answer 7

Pulmonary circulation increases.

Mean pulmonary artery pressures rises only slightly despite the large increase in CO

Question 8

What is effect of aute exercise on mean pulmonary artery pressure?

Answer 8

only rises slgihlty despite large increase in CO

This indicateds a decrase in pulmonary vascular resistsnce (PVR) due to distension and recruitment of pulmonary capillaries

Also redistribution of BF so that all blood flows mroe uniformly to all parts of lung

Question 9

What happens to minute ventilation (VE) as pulmonary BF increases? What does this do with gas transfer

Answer 9

both VE and alveolar ventilation (VA) increase.

The lung transfers ore oxygena nd CO2

Question 10

What is AT?

Answer 10

Threshold for anaerobic metabolism.

Above AT, lactic acid bulids up

Question 11

What increases at a faster ate, VE or Q?

Answer 11

VE! because it is easier to increase gas than liquid! (Q = blood flow)

Question 12

Why does RQ go above 1 at AT?

Answer 12

due to H+ buffered by HCO2-

Question 13

What is the VO2 max

Answer 13

Plateu of VO2 as work increases, indicated onset of AT (very heavy exercise)

work rate can increase beyond VO2 max but oxygen uptake will remain flat b/c the CO cannot increase further

Question 14

For normal adults when is VO2 max reached? For world lcass athletes?

Answer 14

normal- 2-3 L/minute (10x resting VO2)

Athlete- > 4L/minutes

Question 15

Is the CV system or repiratory system teh limiting factor during exercise in a normal person?

Answer 15

CV system!

resting minute ventilation can be incrases 20x

CO can only increase about 4-6x

Question 16

Why doesn’t PaCO2 cahnge during mild and moderate exercise?

Answer 16

PaCO2 doesn’t change even though ventilation has increased many fold. This implies a remarkable couplign between ventialationa nd CO2 production that is not dpending on “error signal” from chemoreceptors. At high workloads, lactic acid develops and this add. stimulus causes PaCO2 to decrease. wga

Question 17

What is the effect on long eterm training programs

Answer 17

INcreased max CO due to increased SV

increased oxidative capacity of sk muscle