Alveolar ventilation Flashcards
What is meant by minute ventilation?
Total volume of air moved into the respiratory tract per minute
What is the calculation for minute ventilation?
Respiratory rate x tidal volume
What is the average respiratory rate?
15 breaths/min
What is the average minute ventilation?
0.5L x 15 = 7.5L/min
What is meant by alveolar ventilation?
Volume of air moved into the respiratory part of the respiratory tract per minute
What is the calculaton for alveolar ventilation?
Respiratory rate x (tidal volume - anatomical dead space)
How can a person change their minute/alveolar ventilation?
Changing their respiratory rate
Changing their depth of breathing to change the tidal volume
What is dead space?
Volume of air in the respiratory tract that is not used in gas exchange
What are the types of dead space?
Anatomical dead space
Alveolar dead space
Physiological dead space
What is anatomical dead space?
Volume of air in the conducting part of the respiratory tract
What is the average anatomical dead space?
0.15L out of 0.5L tidal volume
What is the disadvantage of anatomical dead space?
The air in the upper respiratory tract, conducting part is expired before the air in the alveoli
What is alveolar dead space?
Volume of air in alveoli that are only partially functional or non-functional because of poor or absent blood flow through adjacent pulmonary capillaries
What is physiological dead space?
Anatomical dead space + alveolar dead space
What is the average physiological dead space? Why?
Approximately 0.15L
Because alveolar dead space is very small since most alveoli are fully functional