Page 196 - Physiology and Pathophysiology MNU 2024-2025 نظرى

Clinical pharmacy 2024/2025 Level 2 Pharm D Physiology and Pathophysiology (MD303)

5) Total lung capacity (TLC): 6) The vital capacity (VC):

Definition (TV+ERV+IRV+RV) The maximum amount of air expired

from the fully inflated lung, or maximum
inspiratory level.

= (TV + IRV + ERV).

7) Inspiratory capacity (IC): 8) Functional residual capacity (FRC)

Definition The maximum amount of air that can be The volume of the air remaining in the

inspired from the resting end-expiratory lungs after expiration of a normal,

level. resting breath
= (IRV + TV) = (RV + ERV)

2- Dynamic measurements of pulmonary function:

• Used to measure obstructive defects.

• Collect data from the flow rate of expired and inspired air and reflect the state of the airways.

Forced vital capacity (FVC) Maximal voluntary ventilation (MVV)

Definition:
Definition:
The largest volume of gas that can be moved
The largest amount of air that can be expired
into and out of the lungs in 1 min by voluntary
after a maximal inspiratory effort.
effort.
NB

• The major fraction of VC is already exhaled in
• Typically, this is measured over a 15 s
the first second of forced exhalation  FEVi
period and prorated to a minute.
(forced expiratory volume in 1 sec).
• Normal values range from 140 to 180L /min
• Since FEV depends on the personal physical
for healthy adult males.
abilities  FEV1/FVC is used in practice to

compare FEV values of different persons and
to recognize the classes of airway disease.

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