V: Ventilation and Perfusion

Question 1

Total volume mobilized during the total number of exhalations

Answer 1

Ventilation

Question 2

Ventilation equation

Answer 2

Tidal V x Respiratory Rate

Question 3

Standard tidal volume

Answer 3

500mL

Question 4

Standard breathings per minute

Answer 4

15 breaths per minute

Question 5

Normal ventilation is

Answer 5

7500 mL per minute

Question 6

Current volume is made up of

Answer 6

Alveolar volume and physiologically dead space volume VD

Question 7

Subtypes of physiologically dead volume

Answer 7

Anatomically dead space

Alveolar dead space

Question 8

Of the air inspired how much remains in anatomically dead space and how much is actually entering the respiratory zone

Answer 8

Total = 7500mL/min
Air in anatomically dead space = 150mL/min
Air into respiratory zone = 5250mL/min

Question 8

Of the air inspired how much remains in anatomically dead space and how much is actually entering the respiratory zone

Answer 8

Total = 7500mL/min
Air in anatomically dead space = 150mL/min
Air into respiratory zone = 5250mL/min

Question 9

Air entering into respiratory zone =

Answer 9

Alveolar ventilation

Question 10

How is alveolar ventilation measured

Answer 10

CO2 expired, Bohr’s method

Question 11

Is there diffusion in anatomically dead spaces

Answer 11

No

Question 12

How is anatomically dead space measured (Procedure)

Answer 12

Fowler method, where you breath in N2 (measured), then a single O2 breath taken.
O2 will be mixed with N2 in anatomically dead space therefore [N2] exhaled will increase

Question 13

How much air inside alveolar dead space

Answer 13

0 in normal conditions, but relevant in pathology

Question 14

Normal ratio of dead space/tidal volume

Answer 14

0.2 - 0.3

Question 15

PCO2 in alveolar and arterial blood are

Answer 15

IDENTICAL

Question 16

Differences between Fowler and Bohr method

Answer 16

Fowler measured the volume in conduction airways

Bohr measured the volume of the lung that does not clear up CO2

Question 17

In normal conditions, measurements of Fowler and Bohr should be

Answer 17

Equal

Question 18

Does the entire cardiac output pass through pulmonary circulation

Answer 18

Yes, except bronchial and coronary circulation

Question 19

Cardiac output is measured through which method

Answer 19

Thermoregulation method

Question 20

How is the process of thermoregulation

Answer 20

Cold serum administered to right atrium
Travels through circulatory system
When it reached RA again –> drop in venous blood

Question 21

Normal cardiac output

Answer 21

5L

Question 22

How does fluid express different gravities

Answer 22

Through hydrostatic pressure

Question 23

Does perfusion increase down the lung

Answer 23

Yes

Question 24

Does ventilation increase down the lung

Answer 24

Yes

Question 25

Which increases more going down the lung, perfusion or ventilation

Answer 25

Perfusion

Question 26

Is hydrostatic pressure greater or lower at the base of the lung

Answer 26

Greater, it increases going down the lung

Question 27

Consequences of increased hydrostatic pressure at base of lung

Answer 27

Greater perfusion and ventilation

Question 28

What is the ratio of air reaching tissues

Answer 28

V / Q

Question 29

Is ventilation at apex greater than perfusion

Answer 29

Yes

Question 30

If V>Q then

Answer 30

Dead space in APEX

Question 31

If V/Q = 1 then

Answer 31

At middle of lung

Question 32

If V < Q

Answer 32

Shunt at base of lung

Question 33

Pulmonary diffusion at APEX

Answer 33

V/Q > 1 | Alveolar P > Arterial P > Venous P

Question 34

Pulmonary diffusion at MIDDLE LUNG

Answer 34

V/Q = 1 | Arterial P > Alveolar P > Venous P

Question 35

Pulmonary diffusion at BASE

Answer 35

V/Q < 1 | Arterial P > Venous P > Alveolar P

Question 36

Flow at APEX determined by

Answer 36

Atriovenous pressure

Question 37

Flow at MIDDLE determined by

Answer 37

Arterio-alveolar pressure

Question 38

Flow at BASE determined by

Answer 38

Arteriovenous pressure

Question 39

Ventilation perfusion ratio =

Answer 39

0.8

Question 40

If V/Q > 0.8...

Answer 40

Apical zone, dead space

Question 41

If V/Q < 0.8...

Answer 41

Basal space, shunt

Question 42

Is alveolar PO2 smaller than atmospheric PO2

Answer 42

Yes

Question 43

PO2 alveolar

Answer 43

104mmHHg

Question 44

PO2 atmospheric

Answer 44

160mmHg

Question 45

Why does PO2 drop from 160mmHg to 150mmHg entering the airways

Answer 45

Because due to humidification

Question 46

Blood ENTERING alveolar capillary PO2 and PCO2

Answer 46

``` PO2 = 40mmHg PCO2 = 45mmHg ```

Question 47

Blood LEAVING alveolar capillary PO2 and PCO2

Answer 47

PO2 < 100mmHg | PCO2 = 40mmHg

Question 48

In alveolar obstruction what accumulates in the blood

Answer 48

CO2, because there cannot be an effective gas exchange

Question 49

Reaction of organism in blockage situation

Answer 49

Vasodilate to increase perfusion so blood of poorly ventilated capillaries mixed with blood of well ventilated capillaries

Question 50

Result in blood from vasodilation and mixing blood of well and poorly ventilated areas

Answer 50

Decrease in blood [O2]

Question 51

Does vasodilation actually happen then in the organism

Answer 51

No

Question 52

What does ACTUALLY occur in the organism as a response to a shunt

Answer 52

There is vasoconstriction of poorly ventilated areas to prevent a drop in O2

Question 53

What is hypoxia

Answer 53

Decreased O2 in blood

Question 54

How does the organism react to hypoxia

Answer 54

By vasoconstricting vessels of poorly ventilating areas to redirect blood to the good ventilated areas

Question 55

EX. Mountaneers

Answer 55

Decreased barometric pressure --> decreased alveolar O2 --> body reacts by vasoconstricting poorly ventilated areas

Question 56

EX. COPD

Answer 56

Alveoli are obstructed so no gas exchange --> PO2 decreases in alveoli --> vasoconstriction of poorly ventilated areas

Question 57

IN COPD, vasoconstriction of poorly ventilated areas can lead to

Answer 57

Pulmonary hypertension

Question 58

Alveolar obstruction occurs when

Answer 58

Alveoli are obstructed so the blood passing through the capillaries of these alveoli do not carry out the process of gas diffusion

Question 59

Perfusion obstruction occurs when

Answer 59

Alveolar capillaries are obstructed so air enters during respiration but not able to diffuse into blood

Question 60

Airway obstruction equals to

Answer 60

Shunt (at base of lung) because V/Q < 0.8 | Because there is little ventilation and great perfusion due to alvoelar obstruction

Question 61

Perfusion obstruction equals to

Answer 61

Anatomical dead space (Apex) because V/Q > 0.8 | Since ventilation is much greater than perfusion due alveolar capillary obstruction

Question 62

What would be the consequence of perfusion obstruction

Answer 62

Thrombus, clot that forms on the wall of a blood vessel

Question 63

What would a thrombus cause

Answer 63

Hypertension

Question 64

Why is PO2 exiting the lung not equal to alveolar 104mmHg

Answer 64

Because the PO2 exiting the lung is a mixture of all exchanges happening at different levels --> 98mmHg