Lung Mechanics Flashcards
What is ventilation?
The process of inspiration and expiration
What is tidal volume?
The volume of air being moved during “quiet” inspiration and expiration
Briefly describe how air moves into the lungs
Intercostal muscles and diaphragm contract, thoracic cavity increases in volume, so the pressure inside drops and air moves in
How are the lungs kept against the chest wall?
Pleural fluid forms seal between lung and thoracic wall
What is the resting expiratory level?
Point just after expiration when forces are equal and opposite
What is intrapleural pressure?
negative pressure in the pleural cavity that stays consistent, caused by visceral and parietal pleura pulling in opposite directions
Name 3 muscles used in forced inspiration
SCM, pec major, scalene
Name 2 muscles used in forced expiration
Internal intercostals and abdominal wall muscles
What is compliance?
The lungs ability the stretch, determined by elastic tissue and surface tension of fluid around alveoli
What does surfactant do?
Reduce surface tension on alveoli, so that despite being varied in size they have equal pressure and prevents collapse of smaller ones
Which cells secrete surfactant?
Type 2 pneumocytes
Where is the highest resistance to flow in a normal lung?
upper respiratory tree, trachea and large bronchi
