Respiratory [Perfusion & Flow]

Question 1

The pul vein is contaminated by blood from the ___ that by-passes the lungs, called an ____.

Answer 1

The pul vein is contaminated by blood from the tracheobronchial circulation that by-passes the lungs, called an anatomical shunt.

Question 2

Typical pul pressure =
Typical mean pul pressure =
Typical mean systemic pressure =

Answer 2

28/10mmhg
14
93

Question 3

Blood can only be pumped to a heart of __ at systole and ___ during diastole.

Answer 3

35cm

13cm

Question 4

Mean P eqn =

Answer 4

Diastole + 1/3PP

Question 5

3 features of oedema

Answer 5

Left heart failure
Systemic hypoxia
Breathless ‘dyspnoea’

Question 6

A decrease in resistance of the pulmonary circuit means there is a increase/decrease in ____ causing ___ and ____ of blood vessels that were previously closed.

Answer 6

Decrease
Pulmonary arterial pressure
Distension and recruitment

Question 7

Hypoxia is due to a decrease in ___ levels, causing ___ of alveoli and limits ____ to alveoli with low ____. Hypoxia causes ____ and is due to ___ failure. ____ has the same effect.

Answer 7

Oxygen
Vasoconstriction
Blood flow
Pul hypertension
Right heart failure 
Hypercapnia

Question 8

Hypoxia is due to an ___ response where ____ build up and increase ___ and ____.

Answer 8

Inflammatory
Mucus and fluid
Increase resistance
Increase dead space

Question 9

Blood flowing through poorly ventilated alveoli as found at the top of the lung forms a _____ reducing ___ levels in the ____.

Answer 9

Physiological shunt
PaO2
Pulmonary vein

Question 10

Pressure ratio at top of lungs

Consider PA, Pa, Pv

Answer 10

PA>Pa>Pv

Question 11

Pressure ratio in middle of lung

Consider PA, Pa, Pv

Answer 11

Pa>PA>Pv

Question 12

Pressure at bottom of lung (zone 3)

Consider PA, Pa, Pv

Answer 12

Pa>Pv>PA

Question 13

Ideal ventilation-perfusion ratio =

Answer 13

Alveolar ventilation (f x Vt) / CO

Question 14

Ideal VA/Q is ____ but actual is ___

Answer 14

1

0.8

Question 15

Values

Q =
Va=

Answer 15

Q = 4.9 L/min
Va= 4.24 L/min

Question 16

Factors controlling diffusion across alveolar membrane

Answer 16

Area
Thickness of tissue
Partial p diff across tissue
Solubility of gas
M gas

Question 17

Partial pressure difference:

Alveoli —> blood
Blood —> alveoli

Answer 17

60

6

Question 18

CO2 is ___ more solvable than O2 and diffuses ___ faster. However the lung equilibrium for exchange is similar because _____ and ____.

Answer 18

25x
0.86x
Reaction to release CO2 is slow
Driving F CO2 from blood to alveoli is 10x less than alveolus to blood

Question 19

Diffusion limited

Answer 19

Includes reaction time for bonding with haemoglobin Eg.CO

Question 20

Perfusion limited

Answer 20

Eg. NO or O2. Limit to transport these gases is blood flow

Question 21

Sheet flow describe

Answer 21

Pulmonary capillaries are densely packed around the alveoli such that individual capillary walls blend together leading to a sheet like micro-vascular structure with interstitial pillars

Question 22

Due to gravity, both ventilation and perfusion are lowest/highest in the ___ of the lung. However, as ____ has more mass than ____, the increase in ___ from the apex to the base is greater than the increase in _____. This means the V/Q ratio increases/decreases from the apex to the base.

Answer 22

Apex
Blood
Air
Perfusion
Ventilation 
Decreases