Pulmonary Blood Flow (Part 1)

Question 1

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

Answer 1

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

Question 2

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

Answer 2

Left side of the heart

Pulmonary veins

Question 3

Pulmonary circulation PaO2 in the arteries

Answer 3

40mmHg - low

Question 4

Pulmonary circulation PaCO2 in the arteries

Answer 4

45mmHg - high

Question 5

Function of pulmonary circulation?

Answer 5

Gas exchange

Question 6

Pulmonary circulation response to hypoxia?

Answer 6

Vasoconstriction

Question 7

Systemic circulation PaO2 in the arteries

Answer 7

100mmHg - high

Question 8

Systemic circulation PaCO2 in the arteries

Answer 8

40mmHg - low

Question 9

Function of systemic circulation?

Answer 9

Deliver oxygenated blood to the tissues

Question 10

Systemic circulation response to hypoxia?

Answer 10

Vasodilate - Tries to get more oxygenated blood to the tissues

Question 11

Hypoxic Vasoconstriction

Answer 11

Regional vasoconstriction in the lungs in response to low oxygen

Question 12

What is the purpose of Hypoxic Vasoconstriction?

Answer 12

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

Question 13

What is the mechanism of Hypoxic Vasoconstriction?

Answer 13

Myogenic - smooth muscle contraction

Question 14

What source do Alveolar Capillaries receive blood from?

Answer 14

Right ventricle (high CO2 and low O2)

Question 15

Job of the Alveolar Capillaries?

Answer 15

Gas exchange

Question 16

What source do Extra-Alveolar Capillaries receive blood from?

Answer 16

Left ventricle (high O2 and low CO2)

Question 17

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

Answer 17

1. Systemic veins (azygous) - normal

2. Pulmonary veins (goes back into left atrium)

Question 18

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

Answer 18

Venous Admixture

Question 19

What is Venous Admixture and what does it cause?

Answer 19

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!

Question 20

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

Answer 20

Pulmonary Vascular Resistance

Question 21

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

Answer 21

Much LOWER than compared to the rest of the body

Question 22

What determines the Pulmonary Vascular Resistance?

Answer 22

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

Question 23

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

Answer 23

DECREASES

- More capillaries will open to accommodate the increased cardiac output

Question 24

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

Answer 24

INCREASES

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

Question 25

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

Answer 25

LOW | - it is above the heart

Question 26

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

Answer 26

LOW

Question 27

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

Answer 27

NORMAL | - it is at the level of the heart

Question 28

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

Answer 28

HIGH | - it is below the level of the heart

Question 29

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

Answer 29

HIGH

Question 30

What modulator of pulmonary blood flow causes vasodilation?

Answer 30

Nitric Oxide

Question 31

What modulators of pulmonary blood flow cause vasoconstriction?

Answer 31

Endothelin 1 | Thromboxane A2

Question 32

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

Answer 32

Usually under pathologic conditions

Question 33

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

Answer 33

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

Question 34

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

Answer 34

Starling forces - Hydrostatic - Oncotic

Question 35

Capillary Hydrostatic Pressure pushes fluid?

Answer 35

Out of the capillary into the alveoli

Question 36

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

Answer 36

Due to the negative Intrapleural Pressure in the lungs

Question 37

Tissue Hydrostatic Pressure pushes fluid?

Answer 37

Out of the capillary into the alveoli

Question 38

Capillary Oncotic Pressure pulls fluid?

Answer 38

Out of the alveoli and into the capillary

Question 39

Tissue Oncotic Pressure pulls fluid?

Answer 39

Out of the capillary and into the alveoli

Question 40

What forces favor fluid to move into the alveoli? | BAD

Answer 40

1. Capillary Hydrostatic Pressure 2. Tissue Hydrostatic Pressure 3. Tissue Oncotic Pressure

Question 41

What forces favor fluid to move into the capillary? | GOOD

Answer 41

1. Capillary Oncotic pressure

Question 42

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?

Answer 42

Lymphatics!

Question 43

Job of Lymphatics in order to keep alveoli "dry"?

Answer 43

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

Question 44

2 jobs of ACE in the lungs?

Answer 44

1. Convert Angiotensin 1 to Angiotensin 2 | 2. INactivate Bradykinin