Surfactant Metabolism in the Alveolus

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What is the main effect of exercise on the metabolism of working muscles?

Decreases oxygen demand

Reduces carbon dioxide production

Increases oxygen demand (correct)

Reduces lactic acid production

What is a common physiological response of the respiratory system during moderate to severe levels of exercise?

Reduced removal of carbon dioxide

Decreased lactic acid production

Increased lactic acid production (correct)

Increased oxygen consumption

How do the respiratory and cardiovascular systems respond to the stress caused by exercise?

Increase oxygen supply to exercising tissues (correct)

Decrease heart rate during exercise

Reduce removal of carbon dioxide from the body

Supply less oxygen to exercising tissues

What is a common physiological response of the respiratory system to ascent to altitude?

Initial difficulty in adaptation (D) Signup and view all the answers

What is acclimatization in the context of high-altitude residence?

Changes in lung capacity (D) Signup and view all the answers

What do diving and exercise have in common in relation to the respiratory system?

Both increase demand for oxygen (A) Signup and view all the answers

How does long-term exercise affect the respiratory system according to the text?

Improves overall respiratory function (A) Signup and view all the answers

What happens to lactic acid production during moderate to severe levels of exercise?

It increases (C) Signup and view all the answers

What is a primary demand on the respiratory system during exercise?

Supplying more oxygen to tissues (D) Signup and view all the answers

During exercise, why does the work of breathing increase according to the text?

Larger tidal volumes lead to increased elastic recoil of the lungs. (B) Signup and view all the answers

How does active expiration during exercise affect the work of breathing?

It combines with greater airflow rates to increase the work of breathing. (A) Signup and view all the answers

What happens to minute ventilations above about 40 L/min during exercise?

They are achieved by breathing through the mouth. (C) Signup and view all the answers

Why is inspiratory work increased during exercise?

Due to inward elastic recoil of the chest wall at high thoracic volumes. (B) Signup and view all the answers

What role do airflow rates play in the resistive work of breathing during exercise?

High airflow rates generate greater turbulent airflow and increase resistive work. (A) Signup and view all the answers

How does increased tidal volume affect the work of breathing during exercise?

Lowers the work necessary to overcome chest wall elastic recoil. (C) Signup and view all the answers

During strenuous exercise, the increase in tidal volume mainly occurs at the expense of which lung volume?

Expiratory reserve volume (A) Signup and view all the answers

What is the primary limiting factor for exercise in healthy people according to the text?

Cardiovascular system (D) Signup and view all the answers

During exercise, what contributes to the increase in cardiac output along with an increase in heart rate?

Deeper inspiratory efforts (D) Signup and view all the answers

What happens to arterial PCO2 during strenuous exercise?

It remains relatively constant (B) Signup and view all the answers

What effect do deeper tidal volumes and active expirations during exercise have on pulmonary vascular resistance?

Increase it (D) Signup and view all the answers

What might be slightly elevated during strenuous exercise due to an increase in central blood volume?

Total lung capacity (C) Signup and view all the answers

At what range does the breathing frequency increase in healthy adults during strenuous exercise?

40-50 breaths per minute (B) Signup and view all the answers

What may result in greater ventilation of upper parts of the lung during expiration?

Gravity-related deflation of alveoli (A) Signup and view all the answers

During active expiration, what should be done to the extraalveolar vessels?

Compressed (A) Signup and view all the answers

What is the main reason for the increase in ventilation-perfusion ratios during moderate to severe exercise?

Opening of intrapulmonary arteriovenous shunts (B) Signup and view all the answers

What effect does increased pulmonary artery pressure have on the ventilation-perfusion ratio during exercise?

Increases ventilation-perfusion ratios (B) Signup and view all the answers

What is one potential cause for the decrease in arterial PO2 during severe exercise?

Opening of intrapulmonary arteriovenous shunts (A) Signup and view all the answers

What contributes to the increased (A-a)DO2 in severe exercise?

Decreased mixed venous PO2 (C) Signup and view all the answers

What does the reduced 'scatter' of ventilation-perfusion ratios during exercise suggest?

Better matching of perfusion and ventilation (B) Signup and view all the answers

How do intrapulmonary arteriovenous shunts affect pulmonary vascular pressures during exercise?

Increase to prevent pulmonary edema (A) Signup and view all the answers

What may be a consequence of increased perfusion of poorly ventilated alveoli during exercise?

Reduced arterial PO2 (D) Signup and view all the answers

'Scatter' of ventilation-perfusion ratios can be reduced by which mechanism?

'Shunt-like' areas formation (A) Signup and view all the answers