Resp 2.1 Flashcards
In contrast to expiration, inspiration is
un phénomène actif au cours duquel le volume
thoracique augmente.
Muscles d’inspiration au repos?
Intercosteaux externes, diaphragm
Muscles inspiratoire accessoire? When are they used?
petit pectoral,
scalènes,
sterno-cleido-mastoïdiens
Mostly used when need to have hardcore inspiration due to an exercise
Expiration forcée
Careful, not the same and inspiration force!!
Used when there is some block in the resp system, when we need to cough etc
Need muscles expiratoires accessoires:
muscles abdomineaux, muscles intercosteaux internes
Toute variation de volume entraine
Toute variation de volume entraine une variation de pression. Le produit : P x V = constante P and V are inversely correlated!
2 players in generating the neccessary pressure differences for gas exhange?
The thoracic cage and the lungs
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True or false:
Le volume pulmonaire est égal au volume thoracique
True
les résistances statiques centripètes et centrifuges
centripètes (pulmonaires) et
centrifuges (thoraciques)
Lungs have resistance statique centripede, what does it mean and why?
It means that the lungs have a natural tendancy to collapse on themselves
Two reasons:
Due to the nature of the cells -> elasctic
Due to** tension de surface** du liquide tapissant les alvéoles -> water molecules sorrounding alveoli that want to stay together holding hands
Surfactant and surface tension?
Surfactant (secreted by pnemocytes type 2) is a lipoprotein that reduces the surface tension of the liquid lining the alveoli by reducing the contact of water molecules to water.
It prevents the alveoli from collapsing during expiration
It increases the lung compliance, or the ease of lung expansion
It reduces the work of breathing by decreasing the resistance to airflow in the airways.
What is the effect on lung expiration complience if we fill the lungs with water instead of air
Saline is a solution of salt and water that has a lower surface tension than pure water. This means that saline molecules are less strongly attracted to each other than water molecules, and therefore create less force that tends to collapse the alveoli.
filling the lungs with saline instead of air would increase the lung compliance, -> ease of lung expansion, by making the lung tissue more elastic and flexible
What is propriétés élastiques du thorax (centrifuge)?
The thorac is kinda the inverse of lungs. As much as lungs want to collapse on themselves, the thorac wants to expand
Depending on the muscle work, these two can balance each other, the thorac wanting to expand and the lungs wanting to collapse.
For example during inspiration when the expansion of the thoracic cavity is larger this essentially beats though tendency of the lungs to collapse leading to an expansion of the lungs
propriétés élastiques génèrent la pression intrapleurale négative -> which allows for the expansion of lungs
What is the effect of fibrosis (a disease that decreases lung complienece)
It makes it harder to breather because for the same amout of air, the amount of negative pressure that needs to be generated is higher!
We learned that there is an amount of air volume called “resting volume” why does this happen at a specific point?
As you breathing you create negative pressure inside your lungs
this is done by the expansion of the thorax however at some point after you expanded above 75% of total volume your thorax will start having a tendency to go back to its initial form because you have expanded so much
you can look at the opposite, when you are breathing air out initially it is easier because the thorax as a tendency to go back to a stable point
the reason why we have a resting volume of air is because there’s a specific point where the tendency of the thorax to expand is the same as the tendency of the lungs to collapse -> equilibrium
review page 30
What is Pneumothorax and effect?
accumulation d’air entre la plèvre pariétale et la plèvre viscérale
Effect:
the air in the pleural space creates pressure on the lung, preventing it from expanding normally when you breathe causing the lung to collapse partially or fully.
