Test 3: Wk11: 6 Dynamic Properties of Lungs and Alveolar Ventilation - Dasgupta Flashcards

1
Q

At the top of the chest, gravity acts to — making the pleural pressure

A

pull lung tissue away from the chest wall

more negative

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2
Q

At the bottom of the thorax, gravity — making the pleural pressure

A

presses lung tissue against the chest wall

less negative

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3
Q

Pleural pressure is most

negative at the —, and is least negative in the —

A

uppermost part of the thorax

lowermost part of the thorax

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4
Q

Differences in pleural pressure affect the way alveoli are

A

ventilated in different

parts of the lung.

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5
Q

Inspired air is not distributed evenly in the lungs. This is the result of (2)

A

1) the gradient in pleural pressure

2) the non-linear compliance curve of the lungs

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6
Q

the change in volume is greatest for the units at the —of the lung
and least for the units at the —

A

bottom

top

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7
Q

The lowest part of the lung is ventilated — than the uppermost part

A

more

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8
Q

the bottom part of the lung is — ventilated than the top.

A

always better

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9
Q

compliance is better at

A

the bottom of the lung

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10
Q

areas with different compliance are ventilated

A

differently

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11
Q

DALTON’S LAW OF PARTIAL PRESSURES

A

THE TOTAL PRESSURE OF A
MIXTURE OF GASES IS THE SUM OF THE PARTIAL PRESSURES OF
INDIVIDUAL GASES

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12
Q

PO2

A

partial pressure O2

160mmHg

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13
Q

PN2

A

partial pressure N2

600 mmHg

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14
Q

In room air, the fraction of O2 is —. The fraction of N2 in air is —.

A
  1. 21

0. 79

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15
Q

when room air is drawn into airways another species of gas is added

A

water vapor

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16
Q

at body temperature partial pressure of water vapor is

A

47mmHg

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17
Q

in the airways PO2 PN2 and PH2O

A

PO2 150mmHg

PN2 563 mmHg

PH2O = 47 mmHg

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18
Q

partial pressures in alveoli change because of

A

gas exchange

19
Q

Gas exchange in alveoli removes — O2 and adds — CO2

A

250 ml O2

200ml CO2

20
Q

— mL of air inspired

21
Q

after gas exchange alveoli contain — mL O2, — mL N2, — mL CO2

A

O2 506 mL
N2 2844 mL
CO2 200 mL
total 3550 mL

50 mL H2O excreted was liquid

22
Q

The rate of alveolar ventilation depends on (3)

A

1) Respiratory Rate
2) Tidal Volume
3) Dead Space Volume

23
Q

Rate of Total Ventilation (Minute Ventilation) =

A

VE = Frequency x VT

24
Q

VA stands for

A

alveolar ventilation per minute

25
VD stands for
dead space volume
26
TV stands for
tidal volume
27
VA =
VA = Frequency (VT - VD)
28
Respiratory exchange ratio (R) =
R = Rate of CO2 output / Rate of O2 uptake
29
Anatomical dead space
Volume of air left in conducing airways. | For a normal adult, anatomical dead space = 150 ml
30
Alveolar dead space
is the volume of air left in unperfused alveoli. | The alveolar dead space is very small in a normal adult.
31
Physiological Dead Space
is the summation of alveolar dead space and anatomical dead space. VDtotal = VDanatomical + VDalveolar
32
Bohr Equation for Dead Space
VD/VT = (PaCO2 - PECO2) / PaCO2
33
PeCO2
Partial pressure of CO2 mixed in expired gase
34
PaCO2
Partial pressure of arterial CO2
35
``` if VA* is halved (i.e. hypoventilation), but CO2 production remains the same, the alveolar (A) and arterial (a) PCO2 will ```
double.
36
if VA * is doubled (i.e. hyperventilation), but CO2 production remains the same, the alveolar (A) and arterial (a) PCO2 will
be halved.
37
Alveolar Gas Equation
PAO2 = FIO2 (PB-PH2O) - PaCO2 / 0.8)
38
normal arterial pH normal venous pH
7. 35 - 7.45 | 7. 34 - 7.37
39
Normal arterial PO2 Normal Venous PO2
80-100 mmHg 38-42 mmHg
40
Normal Arterial PCO2 Normal Venous PCO2
35-45 mmHg 44-46 mmHg
41
Normal Arterial HCO3 Normal Venous HCO3
22-26 meg/ml 24-30 meg / ml
42
normal oxygen saturation
95-100%
43
Hypoxemia
low partial pressure of oxygen in arterial blood.
44
Hypercapnia
high partial pressure of carbon dioxide in arterial blood.