Physiology of Gaseous Exchange + Mechanisms of Ventilation Flashcards
What is the pleural cavity?
Virtual space between 2 pleural membranes containing a thin layer of fluid that acts as a lubricant
What does the chest wall want to naturally do?
Wants to recoil outwards
What do the lungs want to naturally do?
Recoil in on itself = collapse
How does the expansion of the thorax cause the expansion of the lungs?
Surface tensions holds 2 pleural membranes together
Chest expands = parietal pleura follows
Visceral pleura follows parietal = surface tension
= pulls lung tissue = expands
What is the respiratory cycle?
1 breath in + 1 breath out
Describe inspiration
ACTIVE
Contraction of inspiratory muscles
Increase thoracic vol
Decrease intrapleural pressure
Increase lung vol
Decrease alveolar pressure
Air into lungs
Describe expiration
PASSIVE
Relaxation of inspiratory muscles
Decrease thoracic vol
Increase intrapleural pressure
Decrease lung vol
Increase alveolar pressure
Air out
What happens to internal intercostal muscles in forced expiration?
Pulled down
What happens to external intercostal muscles in inhalation?
Pulled up
Muscles in inspiration
Contraction increases thoracic capacity
Diaphragm
External intercostal
Accessory = scalenes + sternocleidomastoids
Muscles in expiration
Relaxation decreases thoracic capacity
Elastic recoil of lung
Muscles in forced expiration
Contraction thoracic capacity
Abdominal muscles
Internal intercostals
What is the ideal gas law?
1 mole of gas will occupy 22.4L at atmospheric pressure + 0 degrees irrespective of species
What is Daltons law?
Total pressure is equal to sum of the partial pressure of each gas in the mixture
What is Henrys law?
Concentration of gas dissolved in liquids is proportional to partial pressure in gas phase
Solubility of species is the proportionality constant
