Pulmonary Blood Flow (Part 1) Flashcards Preview

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Flashcards in Pulmonary Blood Flow (Part 1) Deck (44)
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1
Q

Pulmonary circulation receives blood from what side of the heart and what veins?

A
Right side of the heart 
Systemic veins (SVC and IVC)
2
Q

Systemic circulation receives blood from what side of the heart and what veins?

A

Left side of the heart

Pulmonary veins

3
Q

Pulmonary circulation PaO2 in the arteries

A

40mmHg - low

4
Q

Pulmonary circulation PaCO2 in the arteries

A

45mmHg - high

5
Q

Function of pulmonary circulation?

A

Gas exchange

6
Q

Pulmonary circulation response to hypoxia?

A

Vasoconstriction

7
Q

Systemic circulation PaO2 in the arteries

A

100mmHg - high

8
Q

Systemic circulation PaCO2 in the arteries

A

40mmHg - low

9
Q

Function of systemic circulation?

A

Deliver oxygenated blood to the tissues

10
Q

Systemic circulation response to hypoxia?

A

Vasodilate - Tries to get more oxygenated blood to the tissues

11
Q

Hypoxic Vasoconstriction

A

Regional vasoconstriction in the lungs in response to low oxygen

12
Q

What is the purpose of Hypoxic Vasoconstriction?

A

Directs blood to other areas in the lungs with a higher oxygen content

13
Q

What is the mechanism of Hypoxic Vasoconstriction?

A

Myogenic - smooth muscle contraction

14
Q

What source do Alveolar Capillaries receive blood from?

A

Right ventricle (high CO2 and low O2)

15
Q

Job of the Alveolar Capillaries?

A

Gas exchange

16
Q

What source do Extra-Alveolar Capillaries receive blood from?

A

Left ventricle (high O2 and low CO2)

17
Q

What are the 2 paths blood in the Extra-Alveolar Capillaries can return to the heart?

A
  1. Systemic veins (azygous) - normal

2. Pulmonary veins (goes back into left atrium)

18
Q

If blood from the Extra-Alveolar Capillaries returns to the heart via Pulmonary Veins, what does this lead to?

A

Venous Admixture

19
Q

What is Venous Admixture and what does it cause?

A

When Extra-Alveolar Capillaries return their blood to the heart via pulmonary veins, after they received oxygenated blood from the left ventricle already.
This causes the systemic circulation to have REDUCED PaO2 in the arterial blood!

20
Q

Total Peripheral Resistance in systemic circulation is analogous to _____ in the pulmonary circulation

A

Pulmonary Vascular Resistance

21
Q

Pulmonary blood pressure is 25/15. This means that the Pulmonary Vascular Resistance is?

A

Much LOWER than compared to the rest of the body

22
Q

What determines the Pulmonary Vascular Resistance?

A
  1. High NUMBER of capillaries
  2. How many of the capillaries are OPEN at a time
  3. Lung volume
23
Q

During exercise, what happens to the Pulmonary Vascular Resistance and why?

A

DECREASES

- More capillaries will open to accommodate the increased cardiac output

24
Q

At high lung volumes, what happens to the Pulmonary Vascular Resistance and why?

A

INCREASES

- High volumes will stretch the lungs. This stretch compresses the capillaries and increases the resistance

25
Q

What is the blood pressure at the apex of the lung?

A

LOW

- it is above the heart

26
Q

What is the blood flow at the apex of the lung?

A

LOW

27
Q

What is the blood pressure and blood flow at the middle of the lung?

A

NORMAL

- it is at the level of the heart

28
Q

What is the blood pressure at the base of the lung?

A

HIGH

- it is below the level of the heart

29
Q

What is the blood flow at the base of the lung?

A

HIGH

30
Q

What modulator of pulmonary blood flow causes vasodilation?

A

Nitric Oxide

31
Q

What modulators of pulmonary blood flow cause vasoconstriction?

A

Endothelin 1

Thromboxane A2

32
Q

When will Endothelin 1 and Thromboxane A2 cause vasoconstriction of pulmonary blood flow?

A

Usually under pathologic conditions

33
Q

If water/fluid leaks from the capillary into the alveoli, what will this do to oxygen gas exchange into the blood?

A

IMPAIR it!

- Oxygen is not very soluble and has a hard time diffusing from the air across fluid to get to the blood

34
Q

What forces control how much fluid moves from the capillary to the lung?

A

Starling forces

  • Hydrostatic
  • Oncotic
35
Q

Capillary Hydrostatic Pressure pushes fluid?

A

Out of the capillary into the alveoli

36
Q

Tissue Hydrostatic Pressure is negative (reversed direction as expected) .. why?

A

Due to the negative Intrapleural Pressure in the lungs

37
Q

Tissue Hydrostatic Pressure pushes fluid?

A

Out of the capillary into the alveoli

38
Q

Capillary Oncotic Pressure pulls fluid?

A

Out of the alveoli and into the capillary

39
Q

Tissue Oncotic Pressure pulls fluid?

A

Out of the capillary and into the alveoli

40
Q

What forces favor fluid to move into the alveoli?

BAD

A
  1. Capillary Hydrostatic Pressure
  2. Tissue Hydrostatic Pressure
  3. Tissue Oncotic Pressure
41
Q

What forces favor fluid to move into the capillary?

GOOD

A
  1. Capillary Oncotic pressure
42
Q

The starling forces favor fluid to move into the alveoli from the capillary, even though this is bad for oxygen delivery to the blood. What removes that fluid from the alveoli?

A

Lymphatics!

43
Q

Job of Lymphatics in order to keep alveoli “dry”?

A

Remove the unwanted fluid from the alveoli that the starling forces filtered in so that oxygen can diffuse into the blood correctly

44
Q

2 jobs of ACE in the lungs?

A
  1. Convert Angiotensin 1 to Angiotensin 2

2. INactivate Bradykinin