Exam 2 Lecture 9 (2-27-23) Pulmonary (Transpulmonary Pressure, Lung Volumes, Respiration Cycle Graph) Flashcards
At sea level under perfect conditions, the pressure in the atmosphere should be _________ mmHg or _______ atm.
760 mmHg or 1 atm
If we go underground, atmospheric pressure will be higher. if we go to a higher altitude, atmospheric pressure will be lower.
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Why is atmospheric pressure important to the cardiopulmonary system?
Atmospheric pressure (760 mmHg) is whatβs used to force gas into your lungs and into your blood vessels.
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What is our normal alveolar pressure (PA) in between breaths?
0 cmH2O
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What would an alveolar pressure (PA) of +1 cmH2O mean?
PA is higher than outside pressure. The pressure inside the alveoli is higher than the outside pressure, resulting in a delta P that will push air out of the alveoli.
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When we expire, our PA is greater than or less than 0 cm H2O?
Greater than. PA will be +1 cmH20 and will push gas out of the lungs.
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What would an alveolar pressure (PA) of -1 cmH2O mean?
If PA is -1 cmH2O, this will result in a Ξp that would favor air movement into the lungs.
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Under normal conditions, alveolar pressure (PA) oscillates between ________ and ________.
-1 cmH2O (inspiration) and +1 cmH2O (expiration)
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When we inspire, our PA is greater than or less than 0 cm H2O?
Less than. PA will be -1 cmH20 and will pull gas into the lungs.
Define Elastic Recoil Pressure (PEL
or PER).
Refers to the tendency of a stretched out lung to want to recoil on itself.
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What is the relationship between elastic recoil pressure and thoracic pressure?
If thoracic pressure is -5 cmH2O, what would PER be?
The elastic recoil pressure is typically equal and opposite to whatever the thoracic pressure is.
In this situation, as long as alveolar pressure is 0 cmH2O then PER = +5 cmH2O.
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Define Intra Pleural Pressure (PIP or PPL)?
Thoracic Pressure
PIP is -5 cmH2O under normal conditions in between breaths.
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Define transmural pressure.
The difference in pressure between two sides of a βwallβ.
So thereβs a barrier, and weβre looking at whatβs the pressure on one side of the barrier vs the pressure on the other side of the barrier.
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Define transpulmonary pressure.
The difference in pressures between two different sides of a wall, or some kind of barrier.
Difference between the alveolar pressure and the intrapleural pressure in the pleural cavity. The pressure available to move air into the lungs.
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What is the formula for transpulmonary pressure (PTP)?
PTP = PA - PIP
Transpulmonary Pressure = Alveolar Pressure - Intrapleural Pressure
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What is the pressure between the chest wall and the outer border of the lung in between normal breaths?
-5 cmH2O (intrapleural pressure, intrathoracic pressure)
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What is our transpulmonary pressure in between normal breaths?
+5 cmH2O
PTP = PA - PIP
PA = 0 cmH2O
PIP= -5 cmH20
0 - ( -5) = +5
PTP = 5 cmH2O
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The formula for transpulmonary pressure is also equal to the equation of what other type of pressure?
Elastic Recoil Pressure (PER)
PER = PA - PIP
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What is the PER in between normal breaths?
+5 cmH2O
Same formula as transpulmonary pressure (PTP)
In which direction do the chest wall and rib cage tend to recoil?
Chest wall and rib cage like to recoil outward.
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Muscles in between the ribs are called _________.
Intercostal muscles.
Normal resting tone on intercostal muscles tends to want to pull the chest outward.
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What are the two recoiling forces that we have in the pulmonary system?
Inward recoiling forces of the lung.
Outward recoiling forces of the chest wall, ribs, and intercostal muscles.
The opposing recoiling forces contribute to the negative intrapleural pressure in the thorax.
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Why is transpulmonary pressure important to the lungs?
Transpulmonary pressure is the pressure thatβs available to fill the lungs up with air.
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What does positive transpulmonary pressure tell us?
A positive transpulmonary pressure indicates that we have something available to put air into the lungs, whether itβs coming from ourselves or some type of mechanical device.
If the transpulmonary pressure is negative, air will not be able to enter the lungs.
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How much is a normal tidal volume (VT)?
0.5 L
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What is the amount of air that should be in the chest after a normal breath?
What is a term for this volume and what are the components?
3 L
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Functional Residual Capacity (FRC)
FRC is comprised of Expiratory Reserve Volume (ERV) and Residual Volume (RV).
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