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

Question 1

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

Answer 1

pull lung tissue away from the chest wall

more negative

Question 2

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

Answer 2

presses lung tissue against the chest wall

less negative

Question 3

Pleural pressure is most

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

Answer 3

uppermost part of the thorax

lowermost part of the thorax

Question 4

Differences in pleural pressure affect the way alveoli are

Answer 4

ventilated in different

parts of the lung.

Question 5

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

Answer 5

1) the gradient in pleural pressure

2) the non-linear compliance curve of the lungs

Question 6

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

Answer 6

bottom

top

Question 7

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

Answer 7

more

Question 8

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

Answer 8

always better

Question 9

compliance is better at

Answer 9

the bottom of the lung

Question 10

areas with different compliance are ventilated

Answer 10

differently

Question 11

DALTON’S LAW OF PARTIAL PRESSURES

Answer 11

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

Question 12

PO2

Answer 12

partial pressure O2

160mmHg

Question 13

PN2

Answer 13

partial pressure N2

600 mmHg

Question 14

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

Answer 14

0. 21

0. 79

Question 15

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

Answer 15

water vapor

Question 16

at body temperature partial pressure of water vapor is

Answer 16

47mmHg

Question 17

in the airways PO2 PN2 and PH2O

Answer 17

PO2 150mmHg

PN2 563 mmHg

PH2O = 47 mmHg

Question 18

partial pressures in alveoli change because of

Answer 18

gas exchange

Question 19

Gas exchange in alveoli removes — O2 and adds — CO2

Answer 19

250 ml O2

200ml CO2

Question 20

— mL of air inspired

Answer 20

3600

Question 21

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

Answer 21

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

50 mL H2O excreted was liquid

Question 22

The rate of alveolar ventilation depends on (3)

Answer 22

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

Question 23

Rate of Total Ventilation (Minute Ventilation) =

Answer 23

VE = Frequency x VT

Question 24

VA stands for

Answer 24

alveolar ventilation per minute

Question 25

VD stands for

Answer 25

dead space volume

Question 26

TV stands for

Answer 26

tidal volume

Question 27

VA =

Answer 27

VA = Frequency (VT - VD)

Question 28

Respiratory exchange ratio (R) =

Answer 28

R = Rate of CO2 output / Rate of O2 uptake

Question 29

Anatomical dead space

Answer 29

Volume of air left in conducing airways.

For a normal adult, anatomical dead space = 150 ml

Question 30

Alveolar dead space

Answer 30

is the volume of air left in unperfused alveoli.

The alveolar dead space is very small in a normal adult.

Question 31

Physiological Dead Space

Answer 31

is the summation of alveolar dead space and
anatomical dead space.

VDtotal = VDanatomical + VDalveolar

Question 32

Bohr Equation for Dead Space

Answer 32

VD/VT = (PaCO2 - PECO2) / PaCO2

Question 33

PeCO2

Answer 33

Partial pressure of CO2 mixed in expired gase

Question 34

PaCO2

Answer 34

Partial pressure of arterial CO2

Question 35

if VA* is halved (i.e. hypoventilation), but CO2 production remains the same,
the alveolar (A) and arterial (a) PCO2 will

Answer 35

double.

Question 36

if VA * is doubled (i.e. hyperventilation), but CO2 production remains the
same, the alveolar (A) and arterial (a) PCO2 will

Answer 36

be halved.

Question 37

Alveolar Gas Equation

Answer 37

PAO2 = FIO2 (PB-PH2O) - PaCO2 / 0.8)

Question 38

normal arterial pH

normal venous pH

Answer 38

7. 35 - 7.45

7. 34 - 7.37

Question 39

Normal arterial PO2

Normal Venous PO2

Answer 39

80-100 mmHg

38-42 mmHg

Question 40

Normal Arterial PCO2

Normal Venous PCO2

Answer 40

35-45 mmHg

44-46 mmHg

Question 41

Normal Arterial HCO3

Normal Venous HCO3

Answer 41

22-26 meg/ml

24-30 meg / ml

Question 42

normal oxygen saturation

Answer 42

95-100%

Question 43

Hypoxemia

Answer 43

low partial pressure of oxygen in arterial blood.

Question 44

Hypercapnia

Answer 44

high partial pressure of carbon dioxide in arterial blood.