Ventilation Flashcards

1
Q

The volume of gas inspired or expired in a single respiratory cycle

A

tidal volume

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2
Q

the maximum volume of gas that can be inspired starting at the end of normal inspiration

A

inspiratory reserve volume

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3
Q

the maximum volume of gas that can be expired starting from the end of a normal expiration

A

expiratory reserve volume

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4
Q

the volume of gas that remains in the lungs after a maximum expiration

A

residual volume

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5
Q

the total amount of gas in the lungs at the end of a maximum inspiration (the sum of all four lung volumes)

A

total lung capacity

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6
Q

the maximum volume of gas that can be expired after a maximum inspiration

A

vital capacity

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7
Q

the maximum amount of gas that can be inspired starting from FRC

A

inspiratory capacity

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8
Q

the amount of gas in the lungs at the end of a normal expiration

A

functional residual capacity

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9
Q

Three types of dead space:
anatomic dead space
alveolar dead space
physiologic dead space

A

within each tidal volume, there is a volume of gas that does not participate in gas exchange; it is nonfunctional air in terms of diffusion of O2 or CO2

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10
Q

anatomic dead space

A

volume of air contained within the nose, sinuses, pharynx, larynx, and conducting airways

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11
Q

alveolar dead space

A

volume of air contained within non-perfused alveoli

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12
Q

physiologic dead space

A

functional measurement bc it is the sum of anatomic dead space and alveolar dead space

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13
Q

Turbulant Flow

A

disorganized flow, requiring greater pressure v laminar flow

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14
Q

Transitional Flow

A

mixture of turbulant and laminar flow

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15
Q

Laminar flow

A

parabolic profile and smooth flow

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16
Q

Ohm’s Law:
Pressure = Flow * Resistance

17
Q

Poiseullie’s Equation

A

solves for airflow

18
Q

Poiseullie’s Equation Take Home message for increasing airflow

A

increase pressure
increase radius (sympathetics)
reduce viscosity
reduce length

19
Q

Airway Resistance:
when total airway cross sectional area increases

A

airway resistance decreases

20
Q

at large lung volumes…

A

the airways widen and the resistance to airflow decreases

21
Q

at lower lung volumes…

A

the airways become narrow, and airflow resistance increases

22
Q

at very low lung volumes,

A

the small airways might close completely, especially at the bottom of the lung

23
Q

obstructive lung diseases

A

increase in airway resistance
ex: asthma, bronchitis and emphysema

24
Q

Obstructive lung diseases:
emphysema

A

inspiration is easier due to loss of elastin/collagen
expiration is harder due to airway collapse which obstructs air flow
loss of radial traction

25
restrictive lung diseases
expansion of lung is restricted either bc of alterations in lung parenchyma or bc of diease of the pleura, the chest wall, or the neuromuscular apparatus they are characterized by a reduced vital capacity and a small resting lung volume but the airway resistance is not increased
26
pulmonary fibrosis
thickening of interstitial spaces with a resultant increase of radial traction, making it more difficult to expand the lungs during inspiration
27
Forced Vital Capacity Maneuver
accomplished under maximum muscular effect to ensure maximum flow rates at all lung volumes useful index: forced expiratory volume at one second (FEV1) which is often expressed as percentage of FVC ie FEV1/FVC FEV1/FVC should be 80% in health person
28
in obstructive diseases, such as bronchial asthma, FEV1 (forced expiratory volume at one second) is...
reduced much more than FVC (forced vital capacity) , giving a low FEV1/FVC
29
in restrictive diseases, such as pulmonary fibrosis, both FEV1 and FVC are...
reduced and FEV1/FVC may be normal or even increased
30
Flow-Volume Loops: During forced expiration
airways narrow -> increase resistance -> reduces airflow
31
Flow-Volume Loops: During inspiration
airways widen -> decrease resistance -> airflow is maximal
32
in obstructive lung diseases, the flow rate is __ and lung volumes are ___
low; increased
33
in restrictive lung diseases, the flow rate and lung volumes are
reduced and a arched curve may be seen after maximum flow
34
Control of Airway Smooth Muscle Tone is dependent on:
1. autonomic NS activity 2. circulating hormones 3. inhaled particles 4. paracrine signaling
35
Parasympathetic stimulation (ACh) on airway smooth muscle causes
bronchoconstriction
36
sympathetic stimulation (Epi, NE) on airway smooth muscle causes
bronchodilation B2 adrenergic receptors inhalers used by asthmatics contain albuterol (B2 agonist)
37
Control of Airway Smooth Muscle Mast cells within the connective tissue of the lung can release
histamine and leukotrienes which induce constriction they can also increase production of prostaglandins
38
Control of Airway Smooth Muscle Physical irritants and pollutants
activate irritant receptors in the airway submucosa these receptors induce release of ACh from efferent parasympathetic nerves which leads to bronchoconstriction
39