lung mechanics Flashcards

1
Q

how does a gas move

A

high to low P

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2
Q

what muscles are involved in inspiration

A

diaphragm, intercostals, accessory muscles (scalene and SCM)

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3
Q

what point are lungs at after normal exp.

A

FRC

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4
Q

muscles for forced expiration

A

abs and internal intercostals

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5
Q

function of pleaura (2)

A
  1. transmit pressure

2. allow movement

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6
Q

what is typical pleural pressure at FRC

A

-5

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7
Q

when does pleural pressure become positive

A

forced expiration

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8
Q

what happens to lung volumes as pleural pressue become more neg.

A

volumes increase

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9
Q

what happens to alveolar elastic in emphysema and fibrosis

A

emphysema - destroyed

fibrosis - increased

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10
Q

formula for compliance

A

change in V/change in P

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11
Q

how does lung compliance change with volumes?

A

less compliant at very high or low volumes

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12
Q

what can create stiff chest wall

A

obesity, burns, binders, drugs, mulitrib fractures

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13
Q

what 3 things determine lung vol.

A
  1. chest wall compl.
  2. lung compliance
  3. resp. muscle strength
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14
Q

what is formula for laPlaces law for spheres

A

P=(2xsurface tension)/radius

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15
Q

take away from laPlace

A

the smaller the radius, the higher the pressure – gas wants out

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16
Q

what does surface tension on surfactant depend upon?

A

surface area

17
Q

what is purpose of surfactant

A

helps stabilize the sphere size so doesn’t get too big

18
Q

** what are 3 purposes of sufactant

A
  1. stabilizes small alveoli
  2. less tension = less breathing work
  3. keeps lungs dry
19
Q

where in the lung are alveoli most compliant

A

at the base