Pulmonary Blood Flow, Gas Exchange and Transport

Question 1

What two circulation supply the lungs with blood

Answer 1

Bronchial - nutritional

Pulmonary - gas exchange

Question 2

What does the bronchial circulation supply

Answer 2

supplying oxygenated blood from the aorta to the airway smooth muscle, nerves and lung tissue.

Question 3

What kind of pressure system is the pulmonary and bronchial circulation

Answer 3

Pulmonary: high flow low pressure system

Bronchial: Low flow high pressure system

Question 4

What does the pulmonary circulation surround, and what does it supply it with

Answer 4

Surrounds dense capillary network surrounding the alveoli
supplying it with the deoxygenated cardiac output from the right ventricle pulmonary artery and returning oxygenated blood to the left atrium from the pulmonary vein

Question 5

What gradient do the gas exchange at the alveoli follow

Answer 5

the partial pressure gradient (diffusion)

Question 6

What is the rate of the gas diffusion at the alveoli proportional to

Answer 6

partial pressure
gas solubility
available surface area

Question 7

The rate of diffusion is inversely proportional to what at the alveoli

Answer 7

the thickness of the membrane

Question 8

When is diffusion most rapid

Answer 8

over short distances

Question 9

In emphysema what causes the oxygen diffusion level to decrease

Answer 9

the surface area is decreased due to destruction of the alveoli

Question 10

In fibrosis what causes the oxygen diffusion levels to decrease

Answer 10

thickened alveolar membrane

Question 11

What lung disease increases the diffusion distance

Answer 11

pulmonary oedema

Question 12

How does asthma decrease airway ventilation

Answer 12

Increases airway resistance

Question 13

What kind of relationship does ventilation and perfusion have in the alveoli

Answer 13

a complimenting relationship

Question 14

What is perfusion/ Blood flow directly proportional to

Answer 14

vascular resistance

Question 15

What is blood flow distribution influenced by

Answer 15

arterial (hydrostatic) pressure and aveolar pressure

Question 16

Where is the blood flow in the lungs high

Answer 16

The bottom of the lungs then declines with ascending height

Question 17

What would cause blood flow to be high

Answer 17

when arterial pressure exceeds alveolar pressure therefore decreasing vascular resistance

Question 18

Why does the ratio of the ventilation to perfusion decrease from the bottom of the lungs to the apex

Answer 18

as the pulmonary artery pressure is low therefore more susceptible to the effects of gravity and this gives rise to a great degree of variability in blood flow within the lung

Question 19

The matching ratio of the ventilation to perfusion is 1, but where does that majority of mismatch occur

Answer 19

at the apex of the lung

Question 20

If ventilation is less than perfusion in a mismatch what is the outcome

Answer 20

The ventilation of an alveoli is decreased this means that the blood is not oxygenated, therefore the deoxygenated blood will further dilute the oxygenated blood from other alveolus, and CO2 levels increase

Question 21

what is the passage of blood through poorly ventilated alveoli (areas) called

Answer 21

shunt

Question 22

What is the control mechanism in response to a shunt?

Answer 22

Constriction of the under ventilated arteriole diverting the blood flow to better ventilated alveoli

Question 23

What triggers the constriction of the arteriole in the response of a shunt

Answer 23

Hypoxia

Question 24

What does the increasing CO2 levels due to a shunt cause

Answer 24

Mild bronchodilation

Question 25

What create the alveolar dead space

Answer 25

When the ventilation is greater than the perfusion

Question 26

What is the outcome of alveolar dead space

Answer 26

Increase alveolar PO2, which causes pulmonary dilation
Decrease alveolar PCO2, which causes bronchial constriction

The response eventually returns the ventilation perfusion ratio back to one

Question 27

The results of the alveolar dead space is opposite to the effects of what

Answer 27

shunt

Question 28

what is the Physiological Dead Space composed of

Answer 28

alveolar dead space and the anatomical dead space

Question 29

Define Anatomical Dead Space

Answer 29

refers to air in the conducting zone of the respiratory tract unable to participate in gas exchange as walls of airways in this region are to thick

Question 30

What is the pulmonary arterial pressure

Answer 30

systolic - 25mmHg

diastolic - 8mmHg

Question 31

Why is overall rates of equilibrium for oxygen and CO2 similar

Answer 31

because greater pressure difference for oxygen

Moving from 100mmHg to 40mmHg compared to CO2

Question 32

What action is the pulmonary circuit involved in

Answer 32

gas exchange

Question 33

What is the partial pressure gradient of oxygen and CO2 from the alveoli to the blood capillaries

Answer 33

O: 100mmHg to 40mmHg = 60mmHg
CO2: 46mmHg - 40mmHg = 6mmHg

Question 34

How is the partial pressure gradient for CO2 much less that oxygen but displace a similar volume per minute

Answer 34

CO2 is more soluble than oxygen so diffuse easier

Question 35

How many Kpa are their per 1mmHg

Answer 35

0.133

Question 36

What is the abbreviation A and a stand for

Answer 36

A - alveolar pressure

a - arterial blood pressure (oxygenated blood)

Question 37

What is the volume of gas exchange in the alveoli for oxygen and CO2

Answer 37

oxygen - 250ml/min

CO2 - 200ml/min

Question 38

what circulation is shunt more common to occur in

Answer 38

Bronchial circulation

Question 39

what does it mean in the oxyhaemoglobin dissociation curve moves to the right

Answer 39

HB increased affinity