Page 195 - Physiology and Pathophysiology MNU 2024-2025 نظرى

Clinical pharmacy 2024/2025 Level 2 Pharm D Physiology and Pathophysiology (MD303)
Pulmonary function Tests (PFTs)

The primary function of the respiratory system ➔ maintain normality of arterial blood gases ( (PaO2)

(PaCO2).

1- The static lung volumes:

Used to determine restrictive pulmonary diseases  reduction in the person's ability to inflate and
deflate the lungs  some lung volumes and capacities are below normal.

1) Tidal volume (TV): 2) Inspiratory reserve volume (IRV):

The amount of air that moves into the The air inspired with a maximal inspiratory
Definition: lungs with each inspiration (or the effort at the end of a tidal inspiration at

amount that moves out with each rest.

expiration) during breathing.

3) Expiratory reserve volume (ERV): 4) Residual volume (RV):

The volume exhaled by an active Air left in the lungs after an expiration with
Definition:
expiratory effort at the end of a passive maximal effort.

tidal expiration.

NB:

• RV reflects the fact that: after birth, when the lungs have been filled first with air, they are never

completely emptied.
• No expiration ever completely empties the alveoli.

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