Respiration - Lecture 3

Question 1

Which system is the low pressure system?

Answer 1

the pulmonary system

Question 2

Which system is the high pressure system?

Answer 2

the systemic system

Question 3

During its systole, what pressure does the right ventricle develop?

Answer 3

25 mmHg

Question 4

During its systole, what pressure does the left ventricle develop?

Answer 4

120 mmHg

Question 5

What happens to the pressure in the right ventricle when systole ends?

Answer 5

it falls to atmospheric pressure (0)

Question 6

During diastole, what pressure does the pulmonary circulation have?

Answer 6

8 mmHg

Question 7

What is the mean pulmonary arterial pressure?

Answer 7

15 mmHg

Question 8

What is the mean left arterial pressure?

Answer 8

5 mmHg

Question 9

The drop in pressure of the pulmonary circulation is ___ of the drop in pressure of the systemic circulation

Answer 9

1/10

Question 10

What is the formula for flow?

Answer 10

flow = pressure/resistance

Question 11

What does the low vascular resistance in the pulmonary circulation rely on?

Answer 11

the thin walls of the vascular system

Question 12

What allows the lungs to accept the whole cardiac output at all times?

Answer 12

the low vascular resistance and high compliance of the pulmonary circulation

Question 13

What kind of resistance does the pulmonary system have?

Answer 13

low resistance

Question 14

What is the cardiac output of each system?

Answer 14

the same

Question 15

What kind of blood vessel walls are there in the pulmonary circulation?

Answer 15

thin and contain less smooth muscle than comparable vessels in the systemic circulation (offer less resistance)

Question 16

What happens to pulmonary resistance as pulmonary blood flow increases?

Answer 16

it decreases

Question 17

What happens during recruitment of closed vessels?

Answer 17

more blood vessels open = less resistance = more blood flow

Question 18

What happens during distention of blood vessels?

Answer 18

the blood vessels perfused may become wider = less resistance

Question 19

What are the 2 ways resistance can decrease?

Answer 19

recruitment and distention

Question 20

Which drugs cause contraction of smooth muscle?

Answer 20

serotonin, histamine and norepinephrine

Question 21

What do serotonin, histamine and norepinephrine do to pulmonary vascular resistance in larger pulmonary arteries?

Answer 21

they increase it

Question 22

Which drugs relax smooth muscle?

Answer 22

acetylcholine and isoproteranol

Question 23

What does acetylcholine and isoproteranol do to pulmonary vascular resistance?

Answer 23

they increase it

Question 24

What happens in regions of the lungs that are poorly oxygenated?

Answer 24

there is a reflex vasoconstriction

Question 25

What produces nitric oxide?

Answer 25

endothelial cells

Question 26

Which drug relaxes vascular smooth muscle?

Answer 26

nitric oxide

Question 27

What does nitric oxide lead to?

Answer 27

vasodilation

Question 28

What is pulmonary blood flow affected by?

Answer 28

gravity

Question 29

In the upright position, how does blood flow increase?

Answer 29

linearly from top to bottom of the lungs

Question 30

Why are the vessels more distended toward the bottom of the lungs?

Answer 30

because gravity increases vascular pressure

Question 31

How can the pulmonary capillaries be if alveolar pressure is greater than blood pressure in the capillaries?

Answer 31

compressed

Question 32

Where is there more blood flow, at the bottom of the lungs or at the top?

Answer 32

the bottom

Question 33

What causes an uneven distribution of blood flow from the top to bottom of the lung

Answer 33

the hydrostatic pressure of the blood

Question 34

What are the 3 zones of the lungs?

Answer 34

top, middle, bottom

Question 35

How is the pulmonary arterial pressure vs the alveolar pressure in the top zone of the lungs?

Answer 35

pulmonary arterial pressure < the alveolar pressure

Question 36

What happens to the capillaries in the top zone of the lungs?

Answer 36

they are compressed

Question 37

How is the pulmonary arterial pressure vs the alveolar pressure vs venous pressure in the middle zone?

Answer 37

pulmonary arterial pressure > the alveolar pressure > venous pressure

Question 38

What does the flow depend on in the middle zone of the lungs?

Answer 38

the difference between arterial and alveolar pressures

Question 39

How is the pulmonary arterial pressure vs the alveolar pressure vs venous pressure in the bottom zone of the lungs?

Answer 39

pulmonary arterial pressure > venous pressure > alveolar pressure

Question 40

What does the flow depend on in the bottom zone of the lungs?

Answer 40

the arterio-venous pressure difference

Question 41

What affects the distribution of ventilation?

Answer 41

gravity

Question 42

In an upright lung at rest, what happens to the alveoli at the top of the lungs?

Answer 42

they are more opened than the bottom ones

Question 43

During breathing, are the alveoli at the top of the lungs or at the bottom of the lungs opened wider?

Answer 43

the alveoli from the bottom of the lungs

Question 44

Why is there more fresh air at the bottom of the lungs?

Answer 44

because that is where the greater change in pressure happens

Question 45

Ventilation increases slowly from ___ to ___ of the lung but blood flow increases more rapidly.

Answer 45

top, bottom

Question 46

How is the ventilation-perfusion ratio at the top vs at the bottom?

Answer 46

it is abnormally high at the top and much lower at the bottom

Question 47

What is Fick's principle?

Answer 47

O2 consumption per minute is equal to the O2 taken up by the blood in the lungs in one minute