Pressure & Gas Exchange (Respiratory System) Flashcards

1
Q

What is transpulmonary pressure?

A

Transpulmonary pressure is the Pleura difference between the intra-pulmonary pressure found within the lungs and the intrapleural pressure found in the pleura surrounding the lungs.

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2
Q

Describe pleural pressure.

A

Although the pleural pressure changes slightly throughout inhalation and exhalation, it continually remains more negative than atmospheric pressure and is always negative in comparison to the intrapulmonary pressure

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3
Q

What is Boyle’s Law?

A

The inverse relationship between volume and pressure where, as volume increases, pressure decreases and vice versa. The intrapulmonary pressure, or pressure inside the lungs, changes in response to the changes in the volume of the lung.

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4
Q

Describe the relationship between volume and pressure during inhalation and exhalation.

A

Inhalation: increased volume, decreased pressure
Exhalation: decreased volume, increased pressure

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5
Q

What is intrapleural pressure?

A

The slightly negative pressure that exists between the two plerual layers.

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6
Q

Describe the pulmonary pressures during inspiration.

A

Pleural pressure becomes more negative during inspiration, as the recoil tendency for the lungs is higher, which tends to cause transpulmonary to increase as well.

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7
Q

What is brinchodilation?

A

Increase in bronchiole diameter: Epinephrine and sympathetic stimulation; increased airflow

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8
Q

What is bronchcontstriction?

A

Decrease in diameter: Histamine, parasympathetic nerves, cold air, and chemical irritant; Decrease airflow

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9
Q

What is pulmonary compliance?

A

Ease with which the lungs can expand.

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10
Q

How does surfactant affect pulmonary compliance?

A

Surfactant secreted by great cells of alveoli disrupts hydrogen bonds between water molecules and thus reduces the surface tension: increases compliance and decreases resistance.

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11
Q

What is the anatomical dead space?

A

The conduction zone of the airway where there is no gas exchange. (150 mL)

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12
Q

What is the physiologic (total) dead space?

A

Anatomical dead space + pathological alveolar dead space. In pulmonary disease, some alveoli unable to exchange gases.

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13
Q

What is the alveolar ventilation rate (AVR)?

A

Air that ventilates alveoli (350 mL) x respiratory rate (12 bpm) =. 4,200 mL/min; measurement is relevant to the body’s ability to get oxygen to the tissues and dispose of carbon dioxide.

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14
Q

What is the forced expiratory volume (FEV1)?

A

% of vital capacity that can be exhaled in a given time interval; Healthy adult reading is 75% to 85% in 1 second.

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15
Q

What are obstructive disorders?

A

Airway diameter decreased due to inflammation and smooth muscle contractions, or bronchiolar secretion. Reduced FEV1

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16
Q

What are restrictive disorders?

A

Reduction in pulmonary compliance and decrease in gas exchange. Reduced TLC.

17
Q

Describe the composition of air by their partial pressures?

A

PN2 = 78.6% × 760 mm Hg = 597 mm Hg
* PO2 = 20.9% × 760 mm Hg = 159 mm Hg
* PH20 = 0.5% × 760 mm Hg = 3.7 mm Hg*
* PCO2 = 0.04% × 760 mm Hg = 0.3 mm Hg
* PN2 + PO2 + PH20 + PCOz = 760 mm Hg

18
Q

Describe alveolar gas exchange.

A

Air in the alveolus is on contact with a film of water covering the alveolar epithelium, gases diffuse down their gradients until the partial pressure of each gas in the air is equal to its partial pressure.

19
Q

Describe the partial pressures in the lung during pulmonary gas exchange.

A

PO2=104 mm HG in alveolar air versus 40 mm Hg in arriving blood
PCO2 = 46 mm Hg in arriving blood versus 40 mm Hg in alveolar air.

20
Q

Describe the partial pressures in the lung during systemic gas exchange.

A

PO2 = 95 mm Hg in arriving blood versus 40 mm Hg in tissue
PCO2 = 46 mm Hg in tissue versus 40 mm Hg in arriving blood

21
Q
A