Ex Phys final Respiratory responses

What are the three major functions of the respiratory system during exercise?

1. Provide oxygen to the working muscles. 2. Remove carbon dioxide produced by metabolism. 3. Help regulate blood pH.

What is the mechanism of inspiration and expiration, and what role do respiratory muscles play?

Inspiration involves the contraction of the diaphragm and intercostal muscles, expanding the thoracic cavity and drawing air into the lungs. Expiration occurs when these muscles relax, decreasing thoracic volume and pushing air out.

How do PO2 and PCO2 values change from the atmosphere to the lungs and then to arterial blood and back to the lungs in venous blood?

Atmospheric air has high PO2 and low PCO2. In the lungs, PO2 increases and PCO2 decreases as gas exchange occurs. In arterial blood, PO2 is high and PCO2 is low. In venous blood, PO2 decreases and PCO2 increases as oxygen is delivered to tissues and carbon dioxide is collected.

How are O2 and CO2 exchanged and transported within the blood?

O2 is primarily transported bound to hemoglobin in red blood cells, while CO2 is transported as bicarbonate ions, dissolved in plasma, and bound to hemoglobin.

How does the oxyhemoglobin dissociation curve help determine oxygen delivery to tissues?

The curve shows how much oxygen is released from hemoglobin at different PO2 levels. A rightward shift (due to lower pH or higher temperature) indicates increased oxygen release to tissues.

How can the oxyhemoglobin dissociation curve be used to calculate VO2 at rest and during maximal exercise?

By determining the difference in oxygen content in arterial and venous blood and multiplying it by cardiac output, VO2 can be calculated for both rest and maximal exercise.

What roles do hemoglobin and myoglobin play in O2 diffusion from blood to muscle?

Hemoglobin transports O2 in the blood, while myoglobin facilitates O2 storage and diffusion within muscle cells, enhancing oxygen availability during muscle contraction.

How is ventilation controlled at rest and during exercise?

Ventilation is controlled by chemoreceptors that monitor blood gas levels and mechanoreceptors that respond to muscle activity, adjusting breathing rate and depth accordingly.

What is the ventilatory response to incremental exercise, and what is the ventilatory threshold?

The ventilatory response increases with exercise intensity until a threshold is reached, where ventilation increases disproportionately to oxygen consumption, known as the ventilatory threshold.

How does the ventilatory threshold (Tvent) compare to the lactate threshold (LT)?

Tvent typically occurs at a lower intensity than LT, indicating that ventilation increases to meet metabolic demands before lactate accumulation begins.

What is the role of plasma bicarbonate as a buffer for H+ during intense exercise?

Plasma bicarbonate helps neutralize excess hydrogen ions produced during intense exercise, maintaining pH balance and preventing acidosis.

Describe the ventilatory response from rest to submaximal steady-state exercise and during recovery.

Ventilation increases rapidly at the onset of exercise, stabilizes at a steady state during submaximal exercise, and gradually decreases during recovery.

What evidence exists for and against the respiratory system limiting exercise performance?

Evidence for limitation includes reduced arterial oxygen levels at high intensities; evidence against includes studies showing that respiratory muscle fatigue does not significantly impair performance in trained individuals.