30 Questions
What causes the VD/VT ratio to increase?
Increase in tidal volume
What happens to the A-a (alveolar to arterial) PO2 difference during incremental exercise?
It increases
What happens to the oxygen levels in muscle around 50% of maximal work rate?
Oxygen levels plateau
What is the effect of higher intensity exercise on arterial CO2 levels?
Arterial CO2 levels drop off
What is the atmospheric pressure at sea level in mm Hg?
760 mm Hg
What happens to the O2 mm Hg levels from gradients to travel from atmosphere to mitochondria?
O2 mm Hg gradually declines
What is the definition of Exercise-induced arterial hypoxemia (EIAH)?
Condition when O2 carried in arterial blood is severely reduced
What happens to the O2 levels in arterial and alveolar PO2 at maximal exercise compared to rest?
They are higher
What happens to the mean capillary and Mb(myoglobular) O2 levels at rest compared to maximal exercise?
They are higher at rest
What is the effect of altitude on atmospheric pressure?
Pressure is lower at altitude
What is the definition of hyperpnea?
Increased depth and rate of breathing
What is the definition of 'ventilatory drift'?
Rise in ventilation after a period of exercise
What is the measure of gas exchange efficiency?
VD/VT ratio
What is the primary factor responsible for the initial increase in minute ventilation?
Tidal ventilation
What are the three factors that influence ventilation during exercise?
Work rate, fitness level, RBCs amount
What is the function of 'ventilatory drift' after a period of exercise?
Increases alveolar ventilation to help with acid base balance
What is the physiological dead space primarily due to?
Non-perfused alveoli
What is the approximate percentage of oxygen in the room?
21%
What is the definition of respiration?
Process involving energy production with intake of oxygen and release of CO2
What is the formula for minute ventilation (VE)?
Frequency * Tidal volume
What is the formula for alveolar ventilation (VA)?
VA = (VT - VD) * frequency
What is the function of peripheral chemoreceptors?
Detect hypoxia and hypercapnia
What does the oxyhemoglobin dissociation curve represent?
The relationship between oxygen saturation and partial pressure of oxygen
What is the effect of a left shift in the oxyhemoglobin dissociation curve?
Enhances oxygen binding to hemoglobin
Where does the majority of CO2 transport occur in the blood?
As bicarbonate (~75%)
What does the term 'Bohr effect' refer to?
Effect of CO2 on blood pH which decreases affinity of oxygen for hemoglobin
What does the a-vO2 (arterial venous oxygen) difference indicate?
Difference in oxygen extraction by tissues
What is the primary function of hyperpnea?
To increase ventilation during exercise
What is the source of H+ in the bicarbonate buffering system?
Lactic acid, carbonic acid, ketoacidosis
What is the effect of increasing ventilation on the acid-base balance?
Leads to blowing off CO2, correcting acid-base balance
Study Notes
Respiratory Physiology
- The VD/VT ratio increases due to an increase in physiological dead space and a decrease in alveolar ventilation.
Oxygen Levels and Exercise
- Oxygen levels in muscle decrease around 50% of maximal work rate.
- At maximal exercise, arterial PO2 levels decrease, while alveolar PO2 levels remain relatively constant.
- Mean capillary and myoglobin O2 levels decrease at maximal exercise compared to rest.
Gas Exchange and Respiration
- The atmospheric pressure at sea level is 760 mm Hg.
- Oxygen levels (mm Hg) decrease from the atmosphere to the mitochondria due to the gradient of oxygen partial pressure.
- Exercise-induced arterial hypoxemia (EIAH) is a condition where arterial oxygen levels decrease during exercise.
- Respiration is the process of gas exchange between the atmosphere and the body's cells.
Ventilation and Exercise
- Hyperpnea is an increased rate of ventilation, which occurs during exercise.
- Ventilatory drift is a gradual increase in ventilation during prolonged exercise, which helps to maintain arterial CO2 levels.
- The measure of gas exchange efficiency is the VD/VT ratio.
- The primary factor responsible for the initial increase in minute ventilation is the increase in CO2 production.
- Three factors that influence ventilation during exercise are CO2 production, O2 demand, and temperature regulation.
- The function of ventilatory drift is to maintain a stable CO2 level in the blood.
Blood Transport and Oxygen
- The majority of CO2 transport occurs in the blood in the form of bicarbonate ions.
- The oxyhemoglobin dissociation curve represents the binding of oxygen to hemoglobin.
- A left shift in the oxyhemoglobin dissociation curve indicates increased oxygen binding to hemoglobin.
- The a-vO2 difference indicates the amount of oxygen extracted from the blood by the tissues.
Acid-Base Balance
- The source of H+ in the bicarbonate buffering system is the metabolism of CO2 and water.
- Increasing ventilation helps to restore acid-base balance by increasing the exhalation of CO2.
Formulas
- The formula for minute ventilation (VE) is VE = f x VT, where f is the respiratory frequency and VT is the tidal volume.
- The formula for alveolar ventilation (VA) is VA = f x (VT - VD), where VD is the physiological dead space.
Test your knowledge of aerobic energy production, respiration, and ventilation with this quiz. Explore the processes involved in energy production, the exchange of gases, and the factors that influence gas partial pressures.
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