Topic 3-Ventilation And Breathing Cycle

Question 1

What is ventilation

Answer 1

• Flow of air in and out of lungs
• Air flows thru airways when there is a pressure diff between the 2 ends of the airway

Question 2

3 types of pressures

Answer 2

• Atmospheric pressure: Patm (at nose or mouth). Typically 760mmHg at sea level. Just is regular air pressure
• Alveolar pressure: Palm (within alveoli). Changes thru breathing cycle to be more/less/equal to Patm
• Intrapleural pressure: Pip (within pleural cavity). Lower than Patm during normal, quiet breathing. This space has neg pressure, functions as a vacuum to pull lungs open

Question 3

What is tidal volume

Answer 3

vol of air that enters the lungs during a single breath

Question 4

How does air move

Answer 4

By bulk flow from an area of high to low pressure
When Palv is less than Patm, air will enter the lungs
Air flow is F

F=(Palv-Patm)/R

Question 5

Boyles law

Answer 5

P1V1=P2V2

If we have a closed container, down vol up pressure OR up vol down pressure