Blood Flow & Pressure

Question 1

What is the only organ that receives blood flow in excess of cardiac output?

Answer 1

Lungs

Question 2

Why do the lungs receive blood flow in excess of cardiac output?

Answer 2

They receive both total pulmonic flow and some systemic flow simultaneously

Question 3

What makes up the total blood flow to the lungs?

Answer 3

Right ventricular output (pulmonic flow) + bronchial artery flow (small portion of systemic flow)

Question 4

What is the right ventricular output?

Answer 4

100% of cardiac output

Question 5

Bronchial artery flow is about how much of cardiac output?

Answer 5

1-2%

Question 6

What would the total blood flow to the lungs be, percentage-wise?

Answer 6

About 102% of cardiac output

Question 7

Which ventricle pumps 1% more?

Answer 7

Left ventricle

Question 8

Pulmonary lymphatics mainly drain into which major lymphatic duct?

Answer 8

Right lymphatic duct

Question 9

What is the function of the pulmonary lymphatic system?

Answer 9

Remove plasma filtrate, particulate matter absorbed from alveoli, and escaped protein from the vascular system

Question 10

What is the effect of pulmonary lymphatics on pleural pressure?

Answer 10

Helps maintain the negative pressure necessary to pull the alveolar epithelium against capillary endothelium (respiratory membrane) to prevent lung collapse

Question 11

What sided heart failure presents a risk for pulmonary edema?

Answer 11

Left sided heart failure

Question 12

What is a classic sign of pulmonary edema?

Answer 12

Dyspnea

Question 13

What is the pulmonary artery pressure and its mean?

Answer 13

25/8, 15 mmHg

Question 14

What is the aortic artery pressure?

Answer 14

120/80

Question 15

What is the mean pressure of the pulmonary veins and left atrium?

Answer 15

2 mmHg

Question 16

What is pulmonary blood flow equal to?

Answer 16

Cardiac output

Question 17

How is pulmonary blood flow distribution affected by low alveolar oxygen levels?

Answer 17

Causes release of a local vasoconstrictor which automatically redistributes blood to better ventilated areas

Question 18

What is the effect of the SNS on pulmonary vascular smooth muscle?

Answer 18

Mild vasoconstriction

Question 19

What is the effect of the parasympathetic nervous system on pulmonary vascular smooth muscle?

Answer 19

Mild vasodilatation

Question 20

Which receptors mediate the vasoconstriction of pulmonary vascular smooth muscle stimulated by the SNS?

Answer 20

Alpha receptors

Question 21

What happens with alpha blockage during SNS stimulation of the pulmonary vascular smooth muscle?

Answer 21

Vasodilatation as beta receptors are thus unmasked

Question 22

What exhibits the MAJOR constrictor effect on pulmonary vascular smooth muscle?

Answer 22

Low alveolar oxygen levels

Question 23

What occurs in tissues with low oxygen levels: constriction or dilation?

Answer 23

Dilation

Question 24

What occurs in the lungs with low oxygen levels: constriction or dilation?

Answer 24

Constriction

Question 25

Under resting conditions, when does the blood become fully oxygenated?

Answer 25

By the time it has passed the first 1/3 of the pulmonary capillary

Question 26

What is the normal transit time for the oxygenation of the blood in the pulmonary capillary?

Answer 26

.8 seconds

Question 27

How does transit time change under high CO conditions during oxygenation of blood?

Answer 27

Decreased to about .3 seconds (full oxygenation still obtained)

Question 28

What is the limiting factor in exercise when it comes to the oxygenation of blood in the pulmonary capillary?

Answer 28

Stroke volume

Question 29

How does pressure change from the apex of the lung to the base?

Answer 29

Pressure increases due to gravity

Question 30

Describe the flow in the various zones of the pressure differences in the lungs.

Answer 30

Zone 1 - no flow Zone 2 - intermittent flow (apex) Zone 3 - continuous flow (base)

Question 31

Which zone of pulmonary blood flow usually doesn't exist?

Answer 31

Zone 1

Question 32

In which zone of pulmonary blood flow is alveolar pressure greater than capillary pressure?

Answer 32

Zone 1 (no flow)

Question 33

What are the pressure differences during systole in zone 2 of pulmonary blood flow?

Answer 33

Capillary pressure > alveolar pressure

Question 34

What are the pressure differences during diastole in zone 2 of pulmonary blood flow?

Answer 34

Alveolar pressure > capillary pressure

Question 35

In which zone of pulmonary blood flow is capillary pressure greater than alveolar pressure?

Answer 35

Zone 3 (continuous flow)

Question 36

During exercise, the entire lung is in which zone of pulmonary blood flow?

Answer 36

Zone 3 (continuous flow)

Question 37

Where does the body exhibit the greatest amount of pressure: head or feet?

Answer 37

Feet (gravity effect)

Question 38

Which is a greater pulmonary capillary dynamic: filtration or reabsorption forces?

Answer 38

Filtration (15 mmHg compared to 14 mmHg of reabsorption)

Question 39

What type pressure is responsible for the greater amount of filtration forces in the pulmonary capillaries?

Answer 39

Hydrostatic

Question 40

Which type of pressure is associated with filtration: hydrostatic or colloid osmotic?

Answer 40

Hydrostatic (pushes out)

Question 41

Which type of pressure is associated with reabsorption: hydrostatic or colloid osmotic?

Answer 41

Colloid osmotic (pulls in)