lung resistances Part 1: Volume/pressure relationships

Question 1

volume and pressure changes

what muscles initiate changes in intrapleural pressure

Answer 1

respiratory muscles

Question 2

what 2 measurements can infection change the relationship of

Answer 2

volume and pressure

Question 3

How much of a pressure change can 1cm diaphragm movement create in cm H2O and what is this enough to create?

Answer 3

• creates a pressure change of 3 cm H2O
• enough to create a pressure drop in the intrapleural space

Question 3

what is intrapleural pressure

Answer 3

the pressure that is found in between pleural membranes

Question 4

why do the lungs need to be stretchy?

Answer 4

to allow inflation

Question 5

what is boyle law

Answer 5

if you increase volume, you decrease pressure

Question 6

what percent of energy expenditure is used on breathing

Answer 6

5%

Question 7

breathing efforts

what is the name for breathing resistances in a static state and what 2 places are those resistances set up?

Answer 7

Called elastic resistance

resistances are set up in:
- lungs and pleura due to surface tension and surfactant

• chest wall like the skeletal muscles or skin

Question 8

what percentage of breathing resistances one needs to overcome just to breathe, fall in the static state category?

Answer 8

65%

Question 9

what percentage of breathing resistance do you need to overcome to be able to breathe fall into the dynamic state category?

Answer 9

35%

Question 10

what are 2 types of dynamic state breathing resistance?

Answer 10

• tissue viscous resistance
• airway resistance

Question 11

compliance and elastance

what is compliance?

Answer 11

• The change in lung volume that occurs with each unit change in transpulmonary pressure

AKA (distensibility (stretch) of the lung)

Question 12

what is the equation of compliance

Answer 12

C = ∆V/∆P

Question 13

in compliance, how much volume should the lung expand by when pressure changes by 1cmH20

Answer 13

lungs should expand by 200ml

Question 14

what is specific compliance?

Answer 14

this is compliance that is corrected for volume at that specific time

Question 15

what is the equation of specific compliance

Answer 15

Specific compliance = compliance / Volume

Question 16

what does specific compliance do for different volumes

Answer 16

standardizes compliance for different volumes/stages of breathing cycle

Question 17

define elastance

Answer 17

property of resisting deformation (resistance)/ desire to return to original shape

Question 18

what is the equation for elastance

Answer 18

E = 1/C

C = compliance

Question 19

V/P (compliance) relationship

what does the gradient of a lung volume against pleural pressure graph show?

Answer 19

the gradient of a lung volume against pleural pressure graph shows the compliance of the lung

Question 20

which compliance is lower in the lungs: inspiratory or expiratory compliance?

Answer 20

inspiratory compliance is lower in the lungs

Question 21

what does the area between the expiration and inspiration curved lines on a lung volume against pleural pressure graph tell you?

Answer 21

tells you the sum of the non elastic resistances and thus work that needs to be done to overcome these resistances

Question 22

what does the area above the normal straight compliance gradient line in the lung volume against pleural pressure graph show?

Answer 22

tells you the sum of the Elastic resistance and thus work that needs to be done to overcome these resistances

Question 23

how does emphysema effect compliance and elastance?

Answer 23

in emphysema, lungs and alveoli have huge compliance, but not a lot of elastance, so you will find it hard to breath out

Question 24

how does fibrosis effect elastance and compilance

Answer 24

in fibrosis, lungs and alveoli have huge elastance, but not a lot of compliance, so you will find it hard to inflate the lungs/ breath in.