Resp 4 Flashcards

1
Q

Scientists initially assumed the major determinant of lung compliance and lung recoil were….

A

elasticity of pulmonary cells and ECM (elastin and collagen)….FALSE

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2
Q

A major determinant of lungs elastic recoil is…

A

surface tension

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3
Q

surface tension

A

measure of force acting to pull a liquid’s molecules together at an air-water interface

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4
Q

Laplace’s equation

A

P=(2T)/r; T=surface tension (~70dynes/cm), r=bubble radius

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5
Q

surfactant

A

a detergent-like molecule secreted by Type II alveolar cells that reduces surface tension to ~25dynes/cm or less; increasing compliance

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6
Q

What is surfactant composed of?

A

90% phospholipids, 10% protein

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7
Q

How does surfactant reduce surface tension?

A

By decreasing density of water molecules at air-water interfaces

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8
Q

Smaller alveoli have ____ surfactant because…

A

more; it equalizes the pressure between large and small alveoli

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9
Q

Rapidly expanding alveolus vs slowly expanding alveolus

A

-rapidly expanding alveolus greatly reduces surface density of surfactant and increase surface tension and elastic recoil, putting a “brake” on expansion

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10
Q

Infant Respiratory Distress Syndrome

A

affects 1% of new borns; developmental insufficiency of surfactant production and immaturity of the lungs

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11
Q

Prevention of Infant Respiratory Distress Syndrome

A

glucocorticoid injection to the mother

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12
Q

Treatment of Infant Respiratory Distress Syndrome

A
  • artificial surfactant
  • continuous positive airway pressure (CPAP)
  • intubation
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13
Q

90% of airway resistance occurs in….

A

trachea and bronchi

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14
Q

Major determinant of bronchoconstriction/dilation (diameter)

A

CO2

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15
Q

high levels of CO2 cause..

A

dilation

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16
Q

low levels of CO2 cause..

A

constriction

17
Q

histamine

A

released by cells in response to injury and in allergic and inflammatory reactions, causing contraction of smooth muscle and dilation of capillaries

18
Q

Asthmatic airways have…

A

wall-inflamed and thickened

19
Q

Asthmatic airway during attack

A
  • air trapped in alveoli

- tightened smooth muscled

20
Q

In respiratory system effectiveness of ventilation is determined by..

A

total pulmonary ventilation; volume of air moved into and out of lungs each minute

21
Q

total pulmonary ventilation =

A

ventilation rate x tidal volume

22
Q

alveolar ventilation =

A

ventilation rate x (tidal volume - dead space)

23
Q

PO2 and PCO2 remains ______________ during quiet respiration

A

relatively constant

24
Q

As alveolar ventilation increases…. alveolar PO2 ________ and PCO2__________.

A

increases, decreases (and vice versa)

25
Perfusion
blood flow
26
perfusion is absent at the..
apex of lungs due to more negative intrapleural pressure (gravity)
27
Pulmonary arterioles primarily influenced by....
decreasing O2 levels
28
Bronchioles are sensitive to....
CO2 levels; dilating with increasing levels and constriction with decreasing levels