4.2 The Mechanism of Breathing Flashcards
What are the two parts of ventilation?
Inspiration & Expiration
What type of process is breathing in?
An active process
How does inspiration occur?
The external intercostal muscles contract, the ribs are pulled upward and outward, increasing the volume of the thorax which reduces the pressure in the lungs. Atmospheric pressure is greater and so air is forced into the lungs.
What type of process is breathing out?
Passive process
How does breathing out occur?
The internal intercostal muscles contract. The ribs move downwards and inwards, decreasing the volume of the thorax, which increases the pressure in the lungs, making it greater than the atmospheric pressure and air is forced out of the lungs.
What is pulmonary ventilation?
The total volume of air that is moved into the lungs during one minute.
What is the equation for pulmonary ventilation?
Pulmonary ventilation = tidal volume x ventilation rate
