Respiratory Mechanics

Respiratory Mechanics

Air moves down a pressure gradient (at constant temperature & from a region of higher pressure to a region of lower pressure)

Gas molecules in our respiratory system follow the same principles of…

Boyle’s Law

What is the relationship between pressure and volume in the lungs?

Inversely proportional

According to Boyle’s Law, if lung volume decreases, what happens to pressure?

Pressure increases

According to Boyle’s Law, if lung volume increases, what happens to pressure?

Pressure decreases

Gas pressure

force exerted by gas molecules as they collide (more collision —> higher pressure)

Changes in lung volume will result in a change in alveoli volume…

This will influence alveolar pressure.

The volume of the ____ changes during ventilation.

thoracic cavity

What causes air to move into and out of the lungs during ventilation?

by moving down, alternately reversing pressure gradients established between the alveoli and the atmosphere.

The established pressure gradient between the alveoli and the atmosphere is due to the activity….

respiratory muscles

What are the two important pressures for Ventilation?

Atmospheric (barometric) pressure & Intra-alveolar pressure

Atmospheric (barometric) pressure

The pressure exerted by the weight of the air in the atmosphere on objects on Earth’s surface

Atmospheric (barometric) pressure appears at…

760 mmHg

Intra-alveolar pressure

the pressure within the alveoli

How do the alveoli communicate with the atmosphere?

through the conducting airways

When does air flow into or out of the lungs?

any time intra-alveolar pressure differs from atmospheric pressure

Through the act of breathing, air flows down…

its pressure gradient [High] —> [low]

What are the two factors included in breathing?

1. ATM (Constant)

2. IAP —> will change when inhaling and exhaling

We change the IAP by changing the…

volume of the alveoli (Boyle’s law)