Respiratory Volume And Capacity

Tidal Volume:-

👉The amount of air inhaled or exhaled during normal breathing.

👉Approximately 800 ml of air is exchanged during each respiratory cycle.

-Inhalation: About 800 ml of air enters the lungs.

-Exhalation: About 800 ml of air is expelled from the lungs.

Lung Volumes and Capacities:-

👉The lungs can be divided into four different volumes and four different capacities.

👉These subdivisions are represented graphically through spirometry.

👉Different Lung Volumes:-

🌿1.Tidal Volume (TV);

The amount of air inhaled or exhaled during normal breathing.

Value: Approximately 600 ml.

🌿2.Inspiratory Reserve Volume (IRV):

The additional amount of air that can be inhaled after a normal inhalation.Value: About 2500 ml.

🌿3.Expiratory Reserve Volume (ERV):

The additional amount of air that can be exhaled after a normal exhalation.Value: About 1300 ml.

🌿4.Residual Volume (RV):

The amount of air left in the lungs after a forceful exhalation.Value: About 1000 ml.

🌿Dead Space;

Parts of the respiratory system where no gas exchange occurs.

👉Location: Includes the trachea and bronchi.

👉Function: Air that remains in these areas and does not participate in gas exchange is known as dead air space.

Functional Residual Capacity (FRC):-

It is the amount of air exhaled and the amount of air remaining in the lungs after a normal expiration.

Formula: FRC = ERV + RV = 2500 ml

Inspiratory Capacity (IC):-

It is the amount of air that can be inhaled after the end of a normal expiration.

Formula: IC = TV + IRV = 3000 ml

Vital Capacity (VC):-

It is the amount of air that can be forcibly exhaled after a maximal inhalation.

Formula: VC = TV + IRV + ERV = 4500 ml

Total Lung Capacity (TLC):

It is the total volume of air present in the lungs after a maximal inhalation.

Formula: TLC = VC + RV = 4500 ml + 1000 ml = 5500 ml

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