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23 Cards in this Set
- Front
- Back
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What is pulmonary ventilation?
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Breathing- moving air in and out of the lungs
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What is pulmonary diffusion?
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the exchange of O2 and CO2 between the lungs and the blood
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What is capillary diffusion?
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the exchange of O2 and CO2
between the capillary blood and the metabolically active tissue |
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What is Boyle's Law?
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If temperature is constant, P1V1=P2V2
pressureXvolume |
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Describe the process of inspiration?
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An active process where the diaphragm and intercoastal muscles contract to expand the thoracic cage
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Describe the process of expiration
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usually a passive process where the muscles relax, allowing the thoracic cage to return to resting position
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How do you measure lung volumes and capacities?
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Spirometry
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What is tidal volume (TV)?
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The amount of air entering and leaving the lungs with each breath
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What is the vital capacity (VC)?
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the greatest amount of air that can be expired after maximal inspiration
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What is the residual volume (RV)?
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The amount of air remaining in the lungs after max expiration
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What is the total lung capacity (TLC)?
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The sum of the vital capacity and residual volume
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Describe pulmonary diffusion
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The process by which air from the lungs diffuses from the alveoli into the blood and CO2 diffuses from the blood to the lungs
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Discuss blood flow to the lungs at rest. How much? Pressure in arteries? Blood vessels?
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4 to 6 L/min blood flow to lungs at rest (matches systemic circulation flow)
Mean pressure in pulmonary artery is 15mmHg (95 in aorta) Pulmonary blood vessels are thin walled with little smooth muscle |
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What is the most critical factor for gas exchange between the alveoli and blood?
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The pressure gradient between the gases in the two areas
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What is Fick's Law? What do we apply it to?
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The rate of diffusion through a tissue is proportional to the surface area and difference in partial pressure of gas on both side of the tissue.
Applied to oxygen diffusion capacity (rate at which oxygen diffuses from alveoli to the blood) |
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How is oxygen transported through the blood?
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98% bound to hemoglobin (4 mol O2/ 1 mol hemo)
2% dissolved in the plasma |
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How does carbon dioxide cross the pulmonary diffusion membrane so easily even though its pressure gradient is less than oxygen?
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Its membrane solubility is 20 times greater
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What factors during exercise favor oxygen unloading (from hemoglobin) in the muscle?
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Increased acidity (meaning more H+ and DECREASED pH...) and temperature
Decreased PO2 These increases shirt the oxygen dissociation curve to the right |
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How is carbon dioxide transported through the blood?
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As bicarbonate ions
Bound to hemoglobin (which triggers the Bohr effect, shifting the oxygen-hemoglobin dissociation curve to the right) Dissolved in blood plasma |
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What happens to hemoglobin unloading of oxygen when the PO2 decreases?
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It is enhanced (increase)
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What is the a-v)2 difference?
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The difference in oxygen content between arterial and venous blood
This reflects the 4-5mL of O2 per 100 mL of blood taken up by the tissues At rest, arterial blood is about 20ml O2/ 100ml blood |
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Does O2 carrying capacity usually limit athletic performance?
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Nope
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What is the strongest stimulus for the regulation of respiration?
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PCO2
*When CO2 levels become too high, carbonic acid is formed and disociates giving of H+ which increases acidity (decreases pH) |
