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Respiratory 1 > Pulmonary Mechanics > Flashcards

Pulmonary Mechanics Flashcards

1
Q

Diaphragm function, volume, and innervation

A

Inspiratory
2/3 of tidal volume
Phrenic nerves (C3-5)

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2
Q

Inspiratory muscles

A

Diaphragm, ext intercostals

Accessroy (scalenes and sternocleidomastoids)

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3
Q

External intercostals and accessory muscles

A

Ext - 1/3 of inspired…intercostal nerves (T1-T11)

Accessory - scalene and sternocleidomastoid (only labor breathing)

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4
Q

Exp. muscles

A

Abdominal muscles (Rectus abdmonius, ext and internal obliques, tvs. abdominus)…T7-T12

internal intercostals

In healthy, occurs passively so exp only used during labor breathing

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5
Q

Elasticity efinition

A

Expressed by its force-length relationship…smaller slope is harder to stretch

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6
Q

Intrapleural pressure vs. atmospheric and how is it created

A

Negative with respect

Elastic recoils of lung and rib are pulling away from each other creates negative pressure…therefore expansion of the rib cage can expand the lung…think about sliding glass with water in between over each other

Pneumothorax if air enters sthe pleural space

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7
Q

Parietla and visceral pleura attached ot what?

A

Parietal - rib cage

Visceral - outside of the lung

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8
Q

Contributing factors of elastic properties

A 
Elastic tissue 
ST
PV curve of the lung 
Lung compliance 
Surfactant
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9
Q

ST function as an elastic property

A

Reduces the liquid surface to its minimum at the gas-liquid interface

Reduces the SA and V of each alveolus

Contributes more than 50% of the elastic recoil of the lung*****

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10
Q

Lung compliance measurement

A

Change in lung volume generated by each unit change of pleural pressure

Slope of the static pressure volume curve (V/P)

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11
Q

Abnormal compliances caused by lung dz

A

Decreased - pulmonary fibrosis

Increased - emphysema/COPD…some of the patients have lost smaller alveoli so its easier to expand

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12
Q

Atelectasis and compliance

A

Often caused by airway obstruction and non-obstructive complications

Also after surgical anesthesia

Lowers the compliance

PEEP (positive end expiratory pressure) can help prevent it during mechanical ventilation

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13
Q

Surfactant production and when

A

28-32 weeks by type 2 alveolar cells

Reduces ST at epithelial surface and thereby reduces work of inspiratory muscles

Hydrophilic end is near liquid while non-polar end sticks out

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14
Q

Major point of elastic recoil of the chest wall graph

A

THe lung and chest wall equal each other at FRC

Lung and rib cage run parallel to each other

Resting chest wall past 75% of TLC

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15
Q

Implications of changes in FRC

A

FRC is lung volume that is at balanced position between elastic recoils of lung and chest wall

If reduction in compliance, then smaller FRC (pulmonary fibrosis)

If increase in lung compliance, then FRC higher than normal (COPD and emphysema)…this is what causes barrel chest from over-expansion of rib cage

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16
Q

Airway resistance

A

Raw = (Pmo-Palv)/flow

Pmo is typically 0

17
Q

Patterns of airflow in the airways

A

Large - turbulent…generally more resistance
Medium and msall - laminar

Inverse relationship between airway resistance and airwat radius…radius by facotr of 16…only for laminar flow

18
Q

Total cross section area of conducting and respiratory zone

A

Very little change from 0-10, once you reach terminal bronchiole, increases tremendously…more branches means less frcition

19
Q

Airway resistance distribution along the respiratory tract

A

Most resistance occurs in the conducting airways,…almost none bast terminal bronchioles (silent zone)

20
Q

Influence of lung volume on airway resistance

A

As long volume increases, the airway resistance decreases

21
Q

Bronchomotor tone funcctions (physiologic)

A

Airway smooth muscles

Maintains patency - during forced exp or hyperventilation…particularly important in medium and small airways wth no cartilages present in airway walls

Protects against irritants…reflex bronchoconstriction in response to inhaled irrtants mediated through sensory receptors..,minimizes penetration of irritants into lung peripher y

22
Q

Cholinergic
Adrenergic
NANC factors for bronchomotor tone

A

Ach - M3 - ASM contraction

Epi - B2 - ASM relaxation

Nitric oxide - relaxation

Tachykinins - contraction

23
Q

Catecholamines
Locally released mediators

Bronchomotor tone

A

Epinepthrine from the adrenal gland

Histamine and leukotrienes

24
Q

PFV relationship during single breathing cycle

A

BS resp neurons discharge…insp muscles contract…thoracic cavity epands…pleural pressure becomes more negative…lung inflates….alveolar pressures becomes subatmospheric…air flows into the lung until alveolar pressure equals atmospheric pressure

As you expand throacic cage and therefore alveoli, the alveolar pressure falls

25
Q

Resistant and elastic equation

A

Resistive = Pmo - Palv

Elastic = Palv - Pip

Resistive plus elastic is equal to presure gradient between mouth and IP space

Resistance also equal to Raw*Flow

26
Q

Uneven distribution of alevolar ventilation in upright positiion

A

Most in lower zone, then middle, then upper

The pleural pressure is more negative in the upper because the weight of the lung is pulling downward…as a reult, the upper region of the lung is more expanded at FRC

Consequently when the whole lung is expanded from FRC during inspiration, volume expansion is less in the alveoli in the upper region so less ventilation

27
Q

Flow volume curve

A

Patient inhale maximilaly to TLC and then forcibly to RV…basically giving you the VC

Both flow and volume are recorded simulataneously and plotted against each toher

28
Q

Effects of obstructie and restrictive on FV curve

A

Obstructive will move the curve to the left and shrinks

IN restrictive lung dz the volume is smaller and curve is moved to the right…

29
Q

Effort independent portion of exp FV curve

A

PEFR - peak exp flow rate

Will all eventually follow the same path…this is the effort independent portion…closer to the RV at lower lung volume…this is bc of less airway resistance in the small airways

30
Q

FEV1 and FCV

A

FEV1 is how much volume you can get out in 1 second

FVC is forced vital capacity

FEV1/FVC should be about 80% in healthy young adult

31
Q

Obstructive and restirictive effects on FEV1/FVC

A

Obstructive - lowers the percentage by lowering both

Restrictive - raises the percentage but lowers both

32
Q

Factors determining FEV1

A

Effort generated by expiratory muscles

Airway resistance

Elastic recoil of the lung

FEV1 is NOT effort independent***

Respiratory 1 (28 decks)

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