Intro to respiratory system Flashcards
Why do we need a respiratory system?
Creates an interface between environment and CV system to overcome the limitation of distance in the properties of diffusion
What are the two “problems” needed to be overcome by the respiratory system?
Dehydration: for effective diffusion, surface must be thin and moist; respiratory system must operate in an enclosed space. Air movement requires a pump: is initiated by a muscular pump, and air moves from area of higher pressure to area of lower pressure
What are the main functions of the respiratory system?
Gas exchange, control acidity of body, filtering of inhaled air, vocalisation
Which lung has two lobes?
Left
Which lung has three lobes?
Right
Where do the lungs fill?
Entire thoracic cavity with exception of mid-sternal line (for heart, major vessel, oesophagus)
What is the pleural sac?
A double-walled enclosure of lungs filled with pleural fluid
What does the pleural sac do?
Reduces friction from movement on the surface of the lungs; fixes lungs firmly on the thoracic wall without any physical attachements
What is the conductive/dead zone?
Not involved in any gas exchange, acts only as a conduit to transfer air
What makes up the dead zone?
Trachea, bronchi, bronchioles, terminal bronchioles
What is the respiratory zone?
Main interface for gas exchange
What makes up the respiratory zone?
Respiratory bronchioles, alveolar ducts, alveolar sacs
What features of the lungs enables high diffusion rates?
Thin barrier (single layer epithelial cells on alveoli and capillaries) and enormous SA
How does the bronchial tree create a huge CSA?
Undergoes a number of generations (23 divisions)
What is the velocity in the distal parts of the bronchial tree like?
Very low, so gas movement primarily takes place by diffusion
