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CP Exam 2 > Pulmonary Blood flow > Flashcards

Pulmonary Blood flow Flashcards

1
Q

Alveolar capillaries

-Are involved in the exchange of?

A
  • Alveolar capillaries are involved in the exchange of O2 and CO2 between blood and air
  • Millions of alveolar capillaries make it so the alveoli are effectively a sheet of capillaries
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2
Q

Extra-alveolar capillaries

-Arise from?

A

The left ventricle

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3
Q

Extra-alveolar capillaries-function?

A
  • Function as normal systemic capillaries
    • Deliver O2 and CO2 to the tissue of the lungs
    • Provide nutrients/remove waste from lung tissue
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4
Q

Extra-alveolar capillaries-Return to the heart in the pulmonary veins (venous admixture)
-Effect on PaO2 of the arterial blood? PaCO2?

A
  • Reduces the PaO2 of the arterial blood by a few mmHg

- Increases the PaCO2 to a small degree

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5
Q

Alveolar and Extra-alveolar capillaries return to the heart via?

A

Pulmonary veins

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6
Q

Alveolar capillary

- PaO2?
- PaCO2?
- How do these levels compare to those extra-alveolar capillaries?
A
  • Low PaO2
  • High PaCO2
  • These levels are switched in extra-alveolar capillaries
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7
Q

After the alveolar capillaries return via the pulmonary vein, what are the blood gases?

A

High PaO2, Low PaCO2

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8
Q

After the extra-alveolar capillaries return via the pulmonary vein, what are the blood gases?

A

Low PaO2, High PaCO2

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9
Q

Pulmonary vascular resistance

-Important reminder- BP=?

A

BP = CO x TPR
This equation holds true in the lung as well, but substitute in pulmonary vascular resistance (PVR) for TPR
PBP = CO x PVR

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10
Q

Normal pulmonary blood pressure?

Normal cardiac output?

A
  • Normal PBP is 25/15 (MAP = 18)

- Cardiac output is 4 L/min

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11
Q

Systemic side

  • Normal systemic mean arterial pressure?
  • Normal cardiac output?
A
  • Systemic MAP = 90 mmHg

- Cardiac output = 4 L/min

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12
Q

Ratio of PVR to systemic?

A

1/4

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13
Q

Pulmonary vascular resistance is determined by?

A
  • High number of capillaries
  • How many capillaries are open at any given moment in time (it is perfectly normal not to be using all your lungs at rest)
  • Much less sympathetic tone/vasoconstricting forces
  • Lung volume
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14
Q

What is the major role of the vasoconstriction produced by hypoxia?

A

Increase blood flow to areas of the lung with good oxygenation

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15
Q

Pulmonary Vascular Resistance

  • How many capillaries are open at any given moment in time (it is perfectly normal not to be using all your lungs at rest)
    - How does exercise affect PVR?
A

During exercise, PVR drops as more pulmonary capillaries open up to accommodate the increased cardiac output

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16
Q

PVR also depends on lung volume

-What happens to resistance at low or very high lung volumes?

A

The PVR increases a little because the stretch of the tissue compresses the capillaries

17
Q

PVR-normal value?

A

LOW

18
Q

PVR-major constrictor?

A

Hypoxia

19
Q

PVR-Change with exercise?

A

Decreases

20
Q

PVR-Major control?

A

Local

21
Q

Systemic resistance-normal value?

A

Moderate

22
Q

Systemic resistance-major constrictor?

A

Sympathetics

23
Q

Systemic resistance-change with exercise?

A

Decrease

24
Q

Systemic resistance-Major control?

A

ANS

25
Q

Regional blood flow in the lungs?

A
  • As we already know, gravity works on the blood in our bodies- when we stand, the hydrostatic pressure in our legs is increased compared to the level of the heart or in the brain
    • The same is true in the lungs
26
Q

Regional blood flow in the lungs

-Zone 1/apex?

A
  • PA > Pa > PV
  • At the apex of the lung, the blood pressure is reduced because it is slightly above the level of the heart
  • However, the alveoli are somewhat expanded (take as fact for right now)
  • The blood flow is less
27
Q

Regional blood flow in the lungs

-Zone 2/pulmonary artery/vein?

A
  • Pa > PA > PV
  • In the middle regions of the lung, the blood pressure is a little higher because we are at the level of the heart
  • The alveoli are average size (take as fact right now)
  • The blood flow is “normal’
28
Q

Regional blood flow in the lungs

-Zone 3?

A
  • Pa > PV > PA
  • At the base of the lung, the blood pressure is high because we are below the level of the heart
  • The alveoli are smaller (take as fact right now)
  • The blood flow is greater than in other regions of the lung
29
Q

Regional blood flow (short and sweet)

-Apex?

A

High alveolar pressure, low blood pressure: little blood

30
Q

Regional blood flow (short and sweet)

-Middle regions?

A

Normal pressures on both sides: Normal blood

31
Q

Regional blood flow (short and sweet)

-Base?

A

Relatively low alveolar pressure, relatively high blood pressure: lots of blood

32
Q

Chemical Modulators of pulmonary blood flow

  • Nitric oxide
    • produced by?
    • Causes what to happen?
    • Significant role in?
A
  • Produced by the endothelium
  • Causes smooth muscle relaxation and vasodilation
  • Significant role in normal pulmonary blood flow
33
Q

Endothelin 1

  • Produced in?
  • Causes what to happen?
  • Seems to have a role under what type of conditions?
A
  • Produced in the lungs
  • Causes vasoconstriction
  • Seems to be a player under pathologic (not normal) conditions
34
Q

Thromboxane A2

-Treat it the same as endothelin 1-can be found under certain pathologic conditions

A

lalaedsnfd

35
Q

Describe the mechanisms by which the alveoli are kept “dry”

A

The lymphatics! (filter out fluid)

36
Q

Describe the role of the lung in the production of angiotensin 2

A

Has angiotensin converting enzyme (ACE)

-converts angiotensin 1 to angiotensin 2

37
Q

Describe the role of the lung in the metabolism of bradykinin?

A

ACE (angiotensin converting enzyme) inactivates bradykinin

38
Q

Describe the role of the lung in the production/metabolism of arachidonic acid metabolites

A

Leukotrienes and prostaglandins are produced by immune system activation in the lungs
Prostaglandin E2, F2a, and leukotrienes are almost completely removed from the circulation in the lungs

39
Q

Alveolar Capillaries

-Arise from?

A

the right ventricle

CP Exam 2 (12 decks)

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