Ventilation/Perfusion

Question 1

Pulmonary circulation
pulmonary artery has

Answer 1

deoxygenated blood

Question 2

Pulmonary circulation
pulmonary vein has

Answer 2

oxygenated blood

Question 3

The Pulmonary Circulation feeds into

Answer 3

the areas where gas exchange occurs

Question 4

Bronchial circulation:
bronchial arteries deliver

Answer 4

oxygenated blood to larger lung structures

Question 5

Bronchial circulation
deoxygenated blood from larger lung structures (tacheobronchial tree, pulmonary nerves, smooth muscle, etc) is collected by the

Answer 5

azygos and intercostal veins and sent to right atrium

Question 6

Bronchial circulation
pulmonar and cronchial circulations are interconnected. these junctions are called

Answer 6

anastomoses

Question 7

Bronchial circulation
oxygenated blood mixing with de-oxygenated blood is termed

Answer 7

“left to right shunt”

Question 8

Bronchial circulation
when deoxygenated blood mixes with oxygenated arterial blood, it is called a

Answer 8

“right to left shunt”

Question 9

Consequence of Right to Left Shunt or mixing of oxygenated and deoxygenated blood

Answer 9

PO2 will be lower than expected

Question 10

Pulmonary Blood Pressure
Since the mean pulmonary pressure is much ___ than the mean aortic pressure

Answer 10

lower;
the walls of the pulmonary artery and its branches are much thinner and contain much less smooth muscle and elastin than the walls of the aorta

Question 11

pulmonary arterioles are very

Answer 11

thin and contain little smooth muscle

Question 12

systemic arterioles have very thick walls composed mainly of

Answer 12

circularly arranged smooth muscle

Question 13

the pulmonary arterioles do not have the same capacity for___ as systemic arterioles

Answer 13

vasocontriction

Question 14

because cardiac output is high, and P is low, this means

Answer 14

that R (resistance of pulmonary circulation) is very low
almost 1/10th that of the systemic vascular resistance

Question 15

Gravity creates regional differences in pulmonary blood flow by two mechanisms:

Answer 15

1. hydrostatic pressure
2. starling resistors

Question 16

Hydrostatic pressures
the pulmonary arterial and venous blood pressure are both ___ at the lung apex and ___ at the base of the lungs

Answer 16

lower; higher

Question 17

Starling resistors
if alveolar pressure PA is low (no compression of the capillary), blood flow is determined by

Answer 17

arterial pressure (Pa) and venous pressure (Pv)

Question 18

Starling resistors
when alveolar pressure PA > Pv (collapsed capillary)

Answer 18

blood flow is determined by arterial pressure and alveolar pressure

Question 19

we see starling effect at the

Answer 19

apex of lung

Question 20

Pulmonary capillaries are referred to as

Answer 20

alveolar vessels
flow through these vessels is determined by relationship between the alveolar pressure and pressure within them

Question 21

larger pulmonary vessles that run through the lung parenchyma are exposed to radial traction. they are enlarged with inhalation and are called:

Answer 21

extra-alveolar vessels
the caliber of the extra-alveolar vessels is greatly affected by lung volume bc this determines the expanding pull of parenchyma

Question 22

Hypoxia (low PO2) induces

Answer 22

pulmonary vasoconstriction. this directs the blood flow away from the hypoxic region of the lung
this is seen in ppl with pneumonia

Question 23

in systemic capillaries, local areas of hypoxia will cause a

Answer 23

localized vasodilation, increasing blood flow to that region

Question 24

Regional differences in ventilation are due to gravity:
at apex, airways are ___ and intrapleural pressure is ___

Answer 24

more open; more negative

Question 25

Regional differences in ventilation are due to gravity:
at base, airways are ___ and intrapleural pressure is ___

Answer 25

compressed; less negative

Question 26

Ventilation and Perfusion:
at the apex of the lung, V/Q is

Answer 26

> 1

Question 27

Ventilation and Perfusion:
at base of the lung, V/Q is

Answer 27

<1

Question 28

the apex of the lungs is relatively ___ while the base of the lungs is relatively ___

Answer 28

over-ventilated; over-perfused

Question 29

radial traction is ___ at the apex

Answer 29

greater

Question 30

hydrostatic pressure within pulmonary capillaries is greater at the ___ of the lung

Answer 30

base

Question 31

blow flow is greater at the base of the lung bc of

Answer 31

Pa>Pv>PA

Question 32

at alveoli in the apex, a lack of perfusion means

Answer 32

we only add small amount of oxygen to blood and small amount of CO2 removed

Question 33

at alveoli in base, under ventilating and over perfusing

Answer 33

low PO2
more oxygen is added to the blood at the base
more CO2 is removed from body

Question 34

apex intrapleural pressure is ___ negative

Answer 34

more; as compared to the base

Question 35

apex receives ___ tidal volume than the base

Answer 35

less