Understanding Pulmonary Ventilation and Lung Volumes
Pulmonary Ventilation
Pulmonary ventilation, often simply called breathing, is the process of moving air in and out of the lungs. It consists of two phases:
- Inspiration (breathing in): When the diaphragm and external intercostal muscles contract
- Expiration (breathing out): When these muscles relax
Think of pulmonary ventilation as your lungs' way of "taking a breath" - it's the mechanical process of air movement that enables gas exchange.
Understanding Lung Volumes and Capacities
Tidal Volume (TV)
- The amount of air that moves in and out during normal, relaxed breathing
- Typically around 500mL in an average adult
- This is your "regular" breath volume
If you're sitting quietly reading this, each breath you take moves about 500mL of air - that's your tidal volume!
Inspiratory Reserve Volume (IRV)
- The extra air you can forcefully inhale after a normal inspiration
- Usually about 3000mL
- Think of it as your "extra inhalation capacity"
Expiratory Reserve Volume (ERV)
- The additional air you can forcefully exhale after a normal expiration
- Typically around 1200mL
