Blood Supply, Gas Exchange, Ventilation and Perfusion Flashcards
How does alveolar ventilation change from the apex to the base?
It increases as you go towards the base
What arteries supply the bronchial circulation?
Bronchial arteries arising from systemic circualtion
what type of system is the pulmonary circulation in terms of flow and pressure?
High flow, low pressure system
What is ventilation in relation to alveoli?
The amount of air getting to the alveoli in each minute
What is perfusion in relation to alveoli?
The local blood blood flow volume around the alveoli each minute
What is the ideal relationship between ventilation and perfusion?
That they match/compliment each other
What 2 pressures influence the distribution of blood flow in the lung?
Hydrostatic pressure
Alveolar pressure
How does blood blow change in the lung from the base to the apex and why?
Blood flow decreases because arteriolar pressure begins to exceed alveolar pressure
What occurs in the alveolar circulation when there is more perfusion than ventilation?
Dilution of oxygenated blood from better ventilated areas
What does increased PCO2 (i.e. there is more ventilation than perfusion) in an alveoli do to nearby vessels and why?
Constriction of the nearby blood vessel to divert blood to better ventilated alveoli
What does shunt mean?
Passage of blood through poorly ventilated areas of the lung
What is alveolar dead space?
Alveoli that are ventilated but not perfused
