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pulmonary ventilation
inspiration and expiration
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pulmonary diffusion
exchange of O2 and CO2 between the lungs and the blood
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What is the purpose of having air pass through the mouth to get to the lungs?
to warm the air to 37C and to humidify to 100%
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the lungs are suspended by which two pleural sacs?
- parietal: outter layer
- visceral: inner layer
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what is the active process of inspiration and what muscles are used during rest and exercise?
- expansion of chest cavity and lungs and decrease pressure in lungs
- Rest: diaphragm, external intercostals
- exercise: scalenes, sternocleidomastoid, pectorals
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What is the passive process of expiration and what muscles are used during rest and exercise?
- relaxation of the inpiratory muscles and elastic recoil of lung tissue which increases pressure in lungs
- Rest: passive
- Exercise: internal intercostals, latissimus dorsi, quadratus lumborum, abdominals
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What is the lung pressure difference during a cycle of breathing?
- at rest: lung pressure = atmospheric pressure
- lungs expand: lung pressure < atmospheric pressure
- inspiration: air rushes into lungs to balance pressure
- after inspiration: thorax is expanded, lung pressure = atmospheric pressure
- thorax returns to resting dimensions: lung pressure > atmospheric pressure
- expiration: air rushes out of lungs to balance pressure
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what does pulmonary diffusion do and where does it occur?
- replenishes blood's oxygen supply
- removes carbon dioxide from returning venous blood
- occus across the thin respiratory membrane
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Dalton's law
the total pressure of a mixture of gases equals the sum of the partial pressures of the individual gases in the mixture
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Henry's law
gases dissolve in liquids in proportion to their partial pressures, depending on their solubilities in the specific fluids and depending on the temperature
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standard atmospheric pressure (at sea level)
760 mmHg
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What is the % Nitrogen, Oxygen, and CO2 in air
- N2: 79.04%
- O2: 20.93%
- CO2: 0.03%
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What are the partial pressures of Nitrogen, Oxygen, and CO2 at sea level?
- N2: 600.7 mmHg
- O2: 159.1
- CO2: 0.2
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How does O2 excahnge work?
The arterial PO2 is lower than the alveolar PO2 initially (40:105), so O2 rushes into the arterioles so that at the end the venous PO2 is 100. This process occurs in 3/4 sec.
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How does CO2 exchange work?
the arterial PO2 is higher than the alveolar PO2 initially (46:40), so CO2 rushes into the lungs so that the end of the venous PO2 is 40. The CO2 pressure difference is so much smaller because of the solubility of CO2.
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As you exercise, what happens to the diffusion capacity?
increases
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How are O2 and CO2 transported around the body?
- through blood
- O2: < 2% dissolved in plasma (sets up pressure gradient)
- -98% chemically combined with Hb in RBCs (4 heme groups to every 1 O2 molecule)
- CO2: 7-10% dissolved in plasma
- -60-70% chemically combined to make bicarbonate (HCO3-)
- -20-33% reacts with globin portion of Hb to make carbamino compounds
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What does an increase in H+ and temperature do to affect oxygen transport?
allows more oxygen to be unloaded there.
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What environmental factors can affect the % saturation of Hb with O2?
- changes with altitude: increase in RBC but lower PO2 (too many trucks, not enough oxygen)
- changes with anemia: decrease in RBC (enough oxygen, but not enough trucks)
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What are the five factors that affect the saturation of O2 with Hb?
- PO2 in blood: down
- temp: up
- pH: down
- CO2: up
- level of 2,3-DPG in RBC: up
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Why do smokers have a hard time getting enough O2?
Because CO they produce binds better to Hb than O2
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What is the equation used to find pulmonary ventilation?
Ve = TV * f
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dyspnea:
shortness of breath
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hyperventilation
increase in ventilation that exceeds the metabolic need for oxygen
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valsalva maneuver
a breathing technique to trap and pressurize air in the lungs, if held for an extending period, it can reduce cardiac output. Used during heavy lifts
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What is the ventilatory equivalent for O2, at rest, at max exercise?
- ratio between Ve and VO2 in a given time frame
- at rest: Ve/VO2 = 23-28 per minute
- at max exercise: Ve/VO2 = 30L
- Generally it's pretty constant
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ventilatory breakpoint
- point during intense exercise at which ventilation increases disproportionately to the oxygen consumption.
- due to glycolysis
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anaerobic threshold
- point during intense exercise at which metabolism becomes more anaerobic
- sometimes reflects lactate threshold
- seen by increase in Ve/VO2 and no increase in Ve/VCO2
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What is the main respiratory limitation to performance?
- up to 15% of VO2 goes to breathing during exercise compared to 2% at rest.
- ventilation is not usually limiting factor.
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How is the acid-base balance maintained?
HCO3- + H+ => H2CO3 => CO2 + H2O
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Does pH return to normal faster during passive or active recovery?
- active
- increases lactate oxidation
- increases lactate diffusion out of muscle
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