Mechanism of Breathing Flashcards
What is ventilation, and what is it also known as?
The process of moving air in and out of the lungs to maintain diffusion of gases across the alveolar epithelium
BREATHING
What happens when the air pressure of the atmosphere is greater than the air pressure inside the lungs?
Inspiration (inhalation) occurs, where air is forced into the lungs
What happens when the air pressure inside the lungs is greater than the air pressure of the atmosphere?
Expiration (exhalation) occurs, and air is forced out of the lungs
What are the three sets of muscles involved in ventilation?
1/ Diaphragm; a sheet of muscle separating thorax from the abdomen
2/ Internal intercostal muscles; contract leads to expiration (exhalation)
3/ External intercostal muscles; contract leads to inspiration (inhalation)
Is inspiration (inhalation) an active or passive process?
Inspiration (inhalation) is an active process becuase it requires energy
What happens to the intercostal muscles during inspiration (inhalation)?
External intercostal muscles contract and internal intercostal muscles relax
How does the ribcage move during inspiration (inhalation)?
The ribs pulled upwards and outwards, increasing the volume of the thorax
What happens to the diaphragm during inspiration (inhalation)?
The diaphragm muscles contract, causing it to flatten and increase the thoracic volume
How does inspiration (inhalation) create airflow into the lungs?
1/ Thoracic volume increases, which reduces lung pressure
2/ Atmospheric pressure is now greater than pulmonary pressure
3/ Air is forced into the lungs
Is expiration (exhalation) an active or passive process?
Expiration is mostly passive as it does not require much energy
What happens to intercostal muscles during expiration (exhalation)?
Internal intercostal muscles contract, and external intercostal muscles relax
How does the rib cage move during expiration (exhalation)?
The ribs move down and inwards, decreasing the volume of thorax
What happens to the diaphragm during expiration (exhalation)?
The diaphragm muscles relax, and it is pushed up by the contents of the abdomen, which were compressed during inspiration (inhalation)
How does expiration (exhalation) create airflow out of the lungs?
1/ Thoracic volume decreases, which increases lung pressure
2/ Pulmonary pressure is now greater than atmospheric pressure
3/ Air is forced out of the lungs
What plays the main role in quiet breathing?
The recoil of elastic tissue in the lungs is the main cause of air being forced out, like air leaving a balloon
